WO2024000483A1 - 显示面板、显示面板的制备方法和显示装置 - Google Patents

显示面板、显示面板的制备方法和显示装置 Download PDF

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Publication number
WO2024000483A1
WO2024000483A1 PCT/CN2022/103026 CN2022103026W WO2024000483A1 WO 2024000483 A1 WO2024000483 A1 WO 2024000483A1 CN 2022103026 W CN2022103026 W CN 2022103026W WO 2024000483 A1 WO2024000483 A1 WO 2024000483A1
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Prior art keywords
electron transport
transport layer
light
emitting device
thickness
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PCT/CN2022/103026
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English (en)
French (fr)
Inventor
朱友勤
李东
张宜驰
Original Assignee
京东方科技集团股份有限公司
北京京东方技术开发有限公司
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Application filed by 京东方科技集团股份有限公司, 北京京东方技术开发有限公司 filed Critical 京东方科技集团股份有限公司
Priority to PCT/CN2022/103026 priority Critical patent/WO2024000483A1/zh
Priority to CN202280002079.4A priority patent/CN117716805A/zh
Publication of WO2024000483A1 publication Critical patent/WO2024000483A1/zh

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/16—Deposition of organic active material using physical vapour deposition [PVD], e.g. vacuum deposition or sputtering

Definitions

  • the present disclosure relates to the field of display technology, and in particular, to a display panel, a preparation method of a display panel, and a display device.
  • the display panel usually includes multiple light-emitting devices, and the multiple light-emitting devices are used to emit light outward, so that the display panel can realize the image display function.
  • a display panel in a first aspect, includes multiple light emitting devices.
  • Any light-emitting device includes a first electrode, a second electrode, a quantum dot light-emitting layer and at least two electron transport layers.
  • the quantum dot light-emitting layer is located between the first electrode and the second electrode. At least two electron transport layers are stacked and located between the second electrode and the quantum dot light-emitting layer.
  • the plurality of light-emitting devices include a first light-emitting device and a second light-emitting device.
  • the first light-emitting device is used to emit light of a first color
  • the second light-emitting device is used to emit light of a second color.
  • the wavelength of the first color light is greater than that of the second light-emitting device. Color wavelength of light.
  • the number of electron transport layers in the first light-emitting device is less than the number of electron transport layers in the second light-emitting device.
  • the sum of the thicknesses of the at least two electron transport layers in the first light emitting device is greater than the sum of the thicknesses of the at least two electron transport layers in the second light emitting device.
  • the display panel further includes a driving backplane, and a plurality of light-emitting devices are located on one side of the driving backplane.
  • the second electrode is closer to the driving backplane relative to the first electrode.
  • the first light-emitting device includes a first portion of the first electrode, and the second light-emitting device includes a second portion of the first electrode.
  • the distance between the surface of the first part of the first electrode away from the driving backplane and the driving backplane is greater than the distance between the surface of the second part of the first electrode away from the driving backplane and the driving backplane.
  • the at least two electron transport layers in the first light-emitting device include a first electron transport layer and a second electron transport layer, and the electron mobility of the second electron transport layer is smaller than the electron mobility of the first electron transport layer.
  • the first electron transport layer is proximate to the second electrode relative to the second electron transport layer. Moreover, the bottom energy level of the conduction band of the first electron transport layer is smaller than the bottom energy level of the conduction band of the second electron transport layer.
  • the material of the first electron transport layer includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO.
  • the material of the second electron transport layer includes any one of ZnO, GZO, AZO, IZO, IGZO and ZnMgO.
  • the material of the first electron transport layer and the material of the second electron transport layer are different.
  • the material of the second electron transport layer includes ZnMgO.
  • the molar percentage of Mg is greater than 0 and less than or equal to 50%.
  • the sum of the mole percentages of Mg and Zn is 1.
  • the molar percentage of Mg in the second electron transport layer ranges from 1% to 20%.
  • the mole percentage of Mg in the second electron transport layer is approximately 5%.
  • the thickness of the first electron transport layer is greater than 0 nm and less than or equal to 60 nm; and/or the thickness of the second electron transport layer is greater than 0 nm and less than or equal to 60 nm.
  • the thickness of the first electron transport layer is greater than the thickness of the second electron transport layer.
  • the thickness of the first electron transport layer ranges from 30 nm to 50 nm. And/or, the thickness of the second electron transport layer ranges from 1 nm to 30 nm.
  • the thickness of the first electron transport layer is approximately 45 nm. And/or, the thickness of the second electron transport layer is approximately 15 nm.
  • the display panel further includes a third light emitting device.
  • the third light-emitting device is used to emit third color light.
  • the wavelength of the second color light is greater than the wavelength of the third color light.
  • the number of electron transport layers in the first light-emitting device is less than the number of electron transport layers in the third light-emitting device.
  • the at least two electron transport layers of at least one light-emitting device include a third electron transport layer, a fourth electron transport layer and a fifth electron transport layer.
  • the electron mobility of the fourth electron transport layer is smaller than the electron mobility of the third electron transport layer.
  • the electron mobility of the fourth electron transport layer is smaller than the electron mobility of the fifth electron transport layer.
  • the third electron transport layer, the fourth electron transport layer and the fifth electron transport layer are sequentially away from the second electrode along the direction from the second electrode to the quantum dot light-emitting layer.
  • the conduction band bottom energy level of the third electron transport layer is smaller than the conduction band bottom energy level of the fourth electron transport layer.
  • the bottom energy level of the conduction band of the fourth electron transport layer is smaller than the bottom energy level of the conduction band of the fifth electron transport layer.
  • the conduction band bottom energy level of the third electron transport layer is equal to the conduction band bottom energy level of the fifth electron transport layer.
  • the material of the third electron transport layer includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO.
  • the material of the fourth electron transport layer includes any one of ZnO, GZO, AZO, IZO, IGZO and ZnMgO.
  • the material of the fifth electron transport layer includes any one of ZnO, GZO, AZO, IZO, IGZO and ZnMgO. And the material of the fourth electron transport layer is different from the material of the third electron transport layer. And/or, the material of the fourth electron transport layer is different from the material of the fifth electron transport layer.
  • the material of the fourth electron transport layer includes ZnMgO, and the molar percentage of Mg in the fourth electron transport layer is greater than 0 and less than or equal to 50%.
  • the sum of the mole percentages of Mg and Zn is 1.
  • the molar percentage of Mg in the fourth electron transport layer ranges from 1% to 20%.
  • the molar percentage of Mg in the fourth electron transport layer is approximately 8%.
  • the thickness of the third electron transport layer is greater than 0 nm and less than or equal to 40 nm.
  • the thickness of the fourth electron transport layer is greater than 0 nm and less than or equal to 30 nm.
  • the thickness of the fifth electron transport layer is greater than 0 nm and less than or equal to 40 nm.
  • the third light-emitting device includes a third electron transport layer, a fourth electron transport layer and a fifth electron transport layer
  • the thickness of the third electron transport layer is greater than 0 nm and less than or equal to 30 nm.
  • the thickness of the fourth electron transport layer is greater than 0 nm and less than or equal to 20 nm.
  • the thickness of the fifth electron transport layer is greater than 0 nm and less than or equal to 30 nm.
  • the thickness of the third electron transport layer ranges from 5 nm to 20 nm
  • the thickness of the fourth electron transport layer ranges from 5 nm to 20 nm
  • the thickness of the transmission layer ranges from 1 nm to 15 nm
  • the thickness of the fifth electron transport layer ranges from 5 nm to 20 nm.
  • the thickness of the third electron transport layer ranges from 5 nm to 15 nm
  • the thickness of the fourth electron transport layer ranges from 5 nm to 15 nm.
  • the value range is 1 nm to 15 nm
  • the thickness of the fifth electron transport layer is in the range 5 nm to 15 nm.
  • the thickness of the third electron transport layer is about 10.5 nm
  • the thickness of the fourth electron transport layer is approximately 9 nm
  • the thickness of the fifth electron transport layer is approximately 10.5 nm.
  • the first color light is red light
  • the second color light is green light
  • the third color light is blue light
  • the sum of the thicknesses of at least two electron transport layers ranges from 5 nm to 150 nm.
  • the sum of the thicknesses of at least two electron transport layers ranges from 20 nm to 70 nm.
  • the sum of the thicknesses of at least two electron transport layers ranges from 20 nm to 60 nm.
  • the display panel further includes an electron injection layer, a hole injection layer, a hole transport layer, and a light coupling layer.
  • the electron injection layer is located between the second electrode and at least two electron transport layers.
  • the hole injection layer is located between the first electrode and the quantum dot light-emitting layer.
  • the hole transport layer is located between the hole injection layer and the quantum dot light emitting layer.
  • the light coupling layer is located on a side of the first electrode away from the hole injection layer.
  • the preparation method of the display panel includes forming a plurality of light emitting devices.
  • the step of forming a light emitting device includes forming a second electrode.
  • at least two electron transport layers are formed on one side of the second electrode.
  • the material of at least one of the at least two electron transport layers includes an oxide.
  • a quantum dot light-emitting layer is formed on a side of at least two electron transport layers away from the second electrode.
  • a first electrode is formed on a side of the quantum dot light-emitting layer away from the at least two electron transport layers.
  • a display device in yet another aspect, includes the above-mentioned display panel.
  • Figure 1 is a structural diagram of a display device according to some embodiments.
  • Figure 2A is a structural diagram of a display panel according to some embodiments.
  • Figure 2B is a structural diagram of a display panel according to other embodiments.
  • FIG. 3A is a structural diagram of a display panel according to further embodiments.
  • FIG. 3B is a structural diagram of a display panel according to further embodiments.
  • FIG. 3C is a structural diagram of a display panel according to further embodiments.
  • Figure 3D is a structural diagram of a display panel according to still other embodiments.
  • Figure 4 is a graph illustrating the brightness of a light-emitting device as a function of the thickness of the electron transport layer according to some embodiments
  • FIG. 5A is a structural diagram of a display panel according to further embodiments.
  • FIG. 5B is a structural diagram of a display panel according to further embodiments.
  • Figure 6 is a structural diagram of a first light emitting device according to some embodiments.
  • Figure 7A is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to some embodiments.
  • Figure 7B is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to other embodiments.
  • FIG. 7C is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to further embodiments.
  • FIG. 7D is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to further embodiments.
  • Figure 8 is an energy level structure diagram of a light-emitting device according to some embodiments.
  • Figure 9A is a graph of current density as a function of voltage according to some embodiments.
  • Figure 9B is a graph of changes in luminous brightness with voltage according to some embodiments.
  • Figure 9C is a graph of external quantum efficiency as a function of voltage according to some embodiments.
  • Figure 10A is a graph of current density as a function of voltage according to other embodiments.
  • Figure 10B is a graph of changes in luminous brightness with voltage according to other embodiments.
  • Figure 10C is a graph of changes in external quantum efficiency with voltage according to other embodiments.
  • Figure 11 is a structural diagram of a second light-emitting device and a third light-emitting device according to some embodiments.
  • Figure 12A is an energy level relationship diagram of the third electron transport layer, the fourth electron transport layer and the fifth electron transport layer according to some embodiments;
  • Figure 12B is an energy level relationship diagram of the third electron transport layer, the fourth electron transport layer and the fifth electron transport layer according to other embodiments;
  • Figure 12C is an energy level relationship diagram of the sixth electron transport layer, the seventh electron transport layer, the eighth electron transport layer and the ninth electron transport layer according to some embodiments;
  • Figure 12D is an energy level relationship diagram of the sixth electron transport layer, the seventh electron transport layer, the eighth electron transport layer, the ninth electron transport layer and the tenth electron transport layer according to some embodiments;
  • Figure 13 is an energy level structure diagram of a light-emitting device according to other embodiments.
  • FIG. 14A is a graph of current density as a function of voltage according to further embodiments.
  • Figure 14B is a graph of changes in luminous brightness with voltage according to further embodiments.
  • Figure 14C is a graph of external quantum efficiency as a function of voltage according to further embodiments.
  • Figure 15A is a graph of current density as a function of voltage according to further embodiments.
  • Figure 15B is a graph of changes in luminous brightness with voltage according to further embodiments.
  • Figure 15C is a graph of external quantum efficiency as a function of voltage according to further embodiments.
  • Figure 16 is a flowchart of steps of a method for preparing a light emitting device according to some implementations.
  • first and second are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.
  • At least one of A, B and C has the same meaning as “at least one of A, B or C” and includes the following combinations of A, B and C: A only, B only, C only, A and B The combination of A and C, the combination of B and C, and the combination of A, B and C.
  • a and/or B includes the following three combinations: A only, B only, and a combination of A and B.
  • parallel includes absolutely parallel and approximately parallel, and the acceptable deviation range of approximately parallel may be, for example, a deviation within 5°;
  • perpendicular includes absolutely vertical and approximately vertical, and the acceptable deviation range of approximately vertical may also be, for example, Deviation within 5°.
  • equal includes absolute equality and approximate equality, wherein the difference between the two that may be equal within the acceptable deviation range of approximately equal is less than or equal to 5% of either one, for example.
  • Example embodiments are described herein with reference to cross-sectional illustrations and/or plan views that are idealized illustrations.
  • the thickness of layers and regions are exaggerated for clarity. Accordingly, variations from the shapes in the drawings due, for example, to manufacturing techniques and/or tolerances are contemplated.
  • example embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result from, for example, manufacturing. For example, an etched area shown as a rectangle will typically have curved features. Accordingly, the regions shown in the figures are schematic in nature and their shapes are not intended to illustrate the actual shapes of regions of the device and are not intended to limit the scope of the exemplary embodiments.
  • Figure 1 is a structural diagram of a display device according to some embodiments.
  • display device 200 may be a laptop computer, mobile phone, wireless device, personal data assistant (PDA), handheld or portable computer, GPS receiver/navigator, camera, MP4 video player, video camera, game control Desks, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controls and/or displays, camera view displays (e.g., vehicle Displays for rear-view cameras), electronic photos, electronic billboards or signs, projectors, packaging and aesthetic structures (for example, displays for images of a piece of jewelry), etc.
  • PDA personal data assistant
  • GPS receiver/navigator GPS receiver/navigator
  • camera MP4 video player
  • video camera game control Desks
  • watches clocks
  • calculators television monitors
  • flat panel displays flat panel displays
  • computer monitors computer monitors
  • automotive displays e.g., odometer displays, etc.
  • navigators e.g., odometer displays, etc.
  • the display device 200 includes a display panel 100 .
  • the display panel 100 is used to display image information.
  • the display panel 100 may be used to display static images, such as pictures or photos.
  • the display panel 100 can also be used to display dynamic images, such as videos or game screens.
  • the embodiment of the present disclosure does not further limit the display device 200, and the display panel 100 is illustrated below.
  • Figure 2A is a structural diagram of a display panel according to some embodiments.
  • the display panel 100 includes a plurality of sub-pixels 101 , the plurality of sub-pixels 101 are located in the display area AA of the display panel 100 and are arranged in an array.
  • the sub-pixel 101 is the smallest unit for the display panel 100 to display images.
  • Each sub-pixel 101 can display a single color, such as red, green or blue.
  • the display panel 100 may include a plurality of red sub-pixels, a plurality of green sub-pixels, and a plurality of blue sub-pixels.
  • red light, green light and blue light of different intensities can be obtained, and at least two of the red light, green light and blue light of different intensities can be superimposed to obtain More colors of light are displayed, thereby realizing full-color display of the display panel 100 .
  • FIG. 2B is a structural diagram of a display panel according to other embodiments.
  • the display panel 100 includes a plurality of light emitting devices 110 . It can be understood that one light-emitting device 110 is located in one sub-pixel 101, so that the display panel 100 can implement an image display function.
  • multiple light emitting devices 110 are used to emit light of different colors. For example, one part (two or more) of the plurality of light-emitting devices 110 is used to emit red light, another part (two or more) of the light-emitting devices 110 is used to emit blue light, and another part (two or more) of the light-emitting devices 110 is used to emit blue light. (one or more) light-emitting devices 110 are used to emit green light, so that the display panel 100 can achieve full-color display.
  • the display panel 100 further includes a driving backplane 150 .
  • a plurality of light emitting devices 110 are located on one side of the driving backplane 150 .
  • the plurality of light-emitting devices 110 are electrically connected to the driving backplane 150, and the driving backplane 150 is used to drive the plurality of light-emitting devices 110 to emit light independently, thereby improving the display performance of the display panel 100.
  • the driving backplane 150 includes a substrate 152 and a driving circuit layer 158 .
  • substrate 152 is a rigid substrate. In other examples, substrate 152 is a flexible substrate.
  • the material of the substrate 152 includes any one of plastic, FR-4 grade material, resin, glass, quartz, polyimide, or polymethyl methacrylate (English full name: Polymethyl Methacrylate, English abbreviation PMMA).
  • the driving circuit layer 158 is located on one side of the substrate 152 .
  • a plurality of pixel driving circuits 154 are provided in the driving circuit layer 158.
  • One pixel driving circuit 154 is electrically connected to one light-emitting device 110, so that the driving backplane 150 can realize independent driving of multiple light-emitting devices 110, thereby enabling multiple light-emitting devices to 110 can shine independently.
  • the pixel driving circuit 154 includes a thin film transistor (English full name: Thin Film Transistor, English abbreviation: TFT) and a capacitor, and the thin film transistor and the capacitor are electrically connected.
  • the pixel driving circuit 154 may be a 2T1C pixel driving circuit (that is, including 2 TFTs and 1 capacitor), a 7T1C pixel driving circuit (that is, including 7 TFTs and 1 capacitor), or a 3T1C pixel driving circuit (that is, including 7 TFTs and 1 capacitor). That is to say, it includes 3 TFTs and 1 capacitor) etc.
  • any light emitting device 110 includes a first electrode 122 , a second electrode 124 and a quantum dot light emitting layer 126 .
  • the quantum dot light emitting layer 126 is located between the first electrode 122 and the second electrode 124 .
  • the light-emitting device 110 is a quantum dot electroluminescent diode (Quantum Dot Light-Emitting Diodes, QLED for short). Understandably, QLED has the advantages of narrow luminescence spectrum, high color purity and high luminous efficiency.
  • the first electron electrode 122 is an anode layer (English name: anode), and the second electrode 124 is a cathode layer (English name: cathode). In other examples, the first electrode 122 is a cathode layer and the second electrode 124 is an anode layer. In the embodiment of the present disclosure, the first electrode 122 is used as the anode layer and the second electrode 124 is used as the cathode layer as an example to continue the illustration.
  • the second electrode 124 is located on a side of the driving circuit layer 158 away from the substrate 152 and is electrically connected to the pixel driving circuit 154 .
  • second electrode 124 may be electrically connected to a drive transistor in pixel drive circuit 154 .
  • display panel 100 also includes pixel defining layer 156 .
  • the pixel defining layer 156 is located on a side of the second electrode 124 away from the driving circuit layer 158 .
  • Pixel defining layer 156 has a plurality of openings.
  • the quantum dot light-emitting layer 126 includes a plurality of effective light-emitting parts 1262, and one effective light-emitting part 1262 is located in an opening.
  • the first electrode 122 is located on a side of the quantum dot light-emitting layer 126 away from the second electrode 124 .
  • the first electrode 122 is used to provide holes
  • the second electrode 124 is used to provide electrons.
  • the holes provided by the first electrode 122 and the electrons provided by the second electrode 124 can move toward the quantum dot light-emitting layer 126 and recombine in the quantum dot light-emitting layer 126 to emit light, so that the light-emitting device 110 can emit light.
  • the structure in which the second electrode 124 is close to the driving backplane 150 relative to the first electrode 122 may be called an inverted structure, and the structure in which the second electrode 124 is far away from the driving backplane 150 relative to the first electrode 122 may be called a positive structure.
  • the embodiment of the present disclosure takes an inverted structure (that is, the second electrode 124 is closer to the driving backplane 150 relative to the first electrode 122) as an example for illustration.
  • the quantum dot light-emitting layer 126 is used to emit light.
  • the first electrode 122 is made of a transparent material, so that the light emitted by the quantum dot light-emitting layer 126 can be emitted outward through the first electrode 122 .
  • the light-emitting device 110 has a top-emission structure.
  • the second electrode 124 is made of a transparent material, so that the light emitted by the quantum dot light-emitting layer 126 can be emitted outward through the second electrode 124 .
  • the light emitting device 110 has a bottom emission structure.
  • both the first electrode 122 and the second electrode 124 are made of transparent material, so that the light emitted by the quantum dot light-emitting layer 126 can be emitted outward through the first electrode 122 and the second electrode 124 .
  • the light-emitting device 110 has a double-sided emission structure.
  • the embodiment of the present disclosure takes the light-emitting device 110 as a top-emitting structure as an example for illustration.
  • the display panel 100 further includes an encapsulation layer 160 .
  • the encapsulation layer 160 is located on the side of the light-emitting device 110 away from the driving backplane 150 and plays a role in protecting the light-emitting device 110 .
  • encapsulation layer 160 includes first encapsulation layer 162 , second encapsulation layer 164 , and third encapsulation layer 166 .
  • the first encapsulation layer 162 , the second encapsulation layer 164 and the third encapsulation layer 166 are stacked and arranged in sequence away from the first electrode 122 of the light emitting device 110 .
  • the first encapsulation layer 162 and the third encapsulation layer 166 are inorganic film layers, and the second encapsulation layer 164 is an organic film layer.
  • the encapsulation layer 160 can block external impurities, water or oxygen, and extend the service life of the light-emitting device 110 .
  • FIG. 3A is a structural diagram of a display panel according to further embodiments.
  • FIG. 3B is a structural diagram of a display panel according to further embodiments.
  • FIG. 3C is a structural diagram of a display panel according to further embodiments.
  • the quantum dot light-emitting layer 126 includes quantum dots (English full name: Quantum Dot, English abbreviation: QD) 1261.
  • the quantum dots 1261 may be spherical, tetrahedral, cylindrical, disc-shaped, etc.
  • the quantum dot 1261 may have a core-shell structure, that is, the quantum dot 1261 has a quantum dot core and a quantum dot shell surrounding the quantum dot core.
  • the size of the quantum dot core By adjusting the size of the quantum dot core, the color of the light emitted by the quantum dot light-emitting layer 126 can be adjusted, so that the light-emitting device 110 can emit light of different colors.
  • the quantum dot 1261 has a narrower energy band gap and is therefore configured to emit light of a longer wavelength.
  • the quantum dot 1261 has a wider energy band gap and is therefore configured to emit light with a shorter wavelength.
  • the plurality of light-emitting devices 110 includes a first light-emitting device 112 and a second light-emitting device 114.
  • the first light-emitting device 112 is used to emit light of the first color
  • the second light-emitting device 114 is used to emit light of the first color.
  • Second color light is used to emit light of the first color.
  • the wavelength of the first color light is greater than the wavelength of the second color light.
  • the first color light is red light (wavelength is about 600nm ⁇ 700nm), and the second color light is green light (wavelength is about 500nm ⁇ 570nm).
  • the size of the quantum dot core of the quantum dot 1261 in the first light-emitting device 112 is larger than the size of the quantum dot core of the quantum dot 1261 in the second light-emitting device 114 .
  • the first light-emitting device 112 and the second light-emitting device 114 can emit different colors. Light.
  • the structure of the light-emitting device 110 is illustrated below with reference to FIGS. 3A to 3C .
  • any light-emitting device 110 includes a first electrode 122 , a second electrode 124 and a quantum dot light-emitting layer 126 located between the first electrode 122 and the second electrode 124 .
  • the material of first electrode 122 includes Mg and Ag.
  • the mass ratio of Mg and Ag is 2:8, so that the first electrode 122 can provide more holes.
  • the material of the second electrode 124 includes ITO (English full name: Indium Tin Oxide, Chinese name: Indium Tin Oxide), so that the second electrode 124 can provide more electrons.
  • the thickness h3 of the first electrode 122 ranges from 8 nm to 12 nm.
  • the thickness h3 of the first electrode 122 may range from 9 nm to 11 nm or 9.5 nm to 10.5 nm.
  • the value of the thickness h3 of the first electrode 122 may be 9 nm, 10 nm, or 11 nm.
  • the thickness h4 of the second electrode 124 ranges from 50 nm to 100 nm.
  • the thickness h4 of the second electrode 124 may range from 60 nm to 90 nm or from 70 nm to 80 nm.
  • the value of the thickness h4 of the second electrode 124 may be 60 nm, 70 nm, 80 nm or 90 nm.
  • the thickness h3 of the first electrode 122 is set to a value range of 8 nm to 12 nm
  • the thickness h4 of the second electrode 124 is set to a value range of 50 nm to 100 nm, thereby avoiding the need for the thickness of the first electrode 122 or the second electrode 124.
  • Too small for example, the first electrode 122 is smaller than 8 nm, or the second electrode 124 is smaller than 50 nm
  • the thickness of the first electrode 122 or the second electrode 124 being too large (for example, the first electrode 122 is larger than 12 nm, or the second electrode 124 is smaller than 50 nm).
  • the first electrode 122 can provide sufficient holes for the quantum dot light-emitting layer 126, and the second electrode 124 can provide sufficient electrons for the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110.
  • the quantum dot light-emitting layer 126 can be formed on one side of the second electrode 124 by spin coating a quantum dot solution, blade coating a quantum dot solution, or inkjet printing a quantum dot solution.
  • the quantum dot solution can be a II-VI semiconductor compound (such as CdSe cadmium selenide, ZnTeSe, etc.), a III-V semiconductor compound (such as InP indium phosphide), a IV-VI semiconductor compound (such as PbS lead sulfide) at least one.
  • the quantum dot solution may also be a perovskite quantum dot solution.
  • the thickness h5 of the quantum dot luminescent layer 126 can be controlled by controlling the concentration of the quantum dot solution or the rotation speed of spin coating.
  • the thickness h5 of the quantum dot light-emitting layer 126 ranges from 10 nm to 80 nm.
  • the thickness h5 of the quantum dot light-emitting layer 126 may range from 20 nm to 50 nm or from 25 nm to 40 nm.
  • the thickness h5 of the quantum dot light-emitting layer 126 may be 20 nm, 30 nm, 40 nm, 60 nm, or 75 nm.
  • the thickness h5 of the quantum dot light-emitting layer 126 is set to a value range of 10 nm to 80 nm, which avoids the thickness of the quantum dot light-emitting layer 126 being too small (for example, less than 10 nm) or too large (for example, more than 80 nm), and improves the luminous efficiency of the light-emitting device 110 .
  • the display panel 100 also includes a hole injection layer (full English name: Hole Injection Layer, English abbreviation: HIL) 144.
  • the hole injection layer 144 is located between the first electrode 122 and the quantum dot light emitting layer 126.
  • the material of the hole injection layer 144 includes MoO 3 (Chinese name: molybdenum trioxide).
  • the thickness h8 of the hole injection layer 144 ranges from 2 nm to 20 nm.
  • the thickness h8 of the hole injection layer 144 may range from 3 nm to 17 nm or from 5 nm to 10 nm.
  • the thickness h8 of the hole injection layer 144 may be 5 nm, 8 nm, 10 nm or 12 nm.
  • the hole injection layer 144 by providing the hole injection layer 144, the number of holes in the quantum dot light-emitting layer 126 can be increased, thereby improving the luminous efficiency of the light-emitting device 110.
  • the thickness h8 of the hole injection layer 144 is set to a value range of 2 nm to 20 nm, which avoids the thickness h8 of the hole injection layer 144 being too small (for example, less than 2 nm), or the thickness h8 of the hole injection layer 144 being too large ( For example, greater than 20 nm) to improve the luminous efficiency of the light-emitting device 110.
  • the light emitting device 110 also includes a hole transport layer (English full name: Hole Transport Layer, English abbreviation: HTL) 146.
  • the hole transport layer 146 is located between the hole injection layer 144 and the quantum dot light emitting layer 126 .
  • the hole transport layer 146 plays a role in transporting holes. Therefore, disposing the hole transport layer 146 between the hole injection layer 144 and the quantum dot light-emitting layer 126 can improve the mobility of holes in the first electrode 122, that is, increase the direction of holes in the first electrode 122. The number of quantum dots migrating in the light-emitting layer 126 increases the luminous efficiency of the light-emitting device 110 .
  • hole transport layer 146 is an organic material.
  • the hole transport layer 146 includes a first hole transport layer 1461 and a second hole transport layer 1462 , and the first hole transport layer 1462 is quantum close to the second hole transport layer 1462 .
  • Point light-emitting layer 126 Point light-emitting layer 126.
  • the material of the first hole transport layer 1461 includes TCTA (Chinese name: 4,4',4′′-tris(carbazol-9-yl)triphenylamine), and the material of the second hole transport layer 1462 includes NPB. (Chinese name: N,N'-bis(naphthyl-1-yl)-N,N'-diphenyl-benzidine).
  • the thickness h6 of the first hole transport layer 1461 ranges from 2 nm to 20 nm.
  • the thickness h6 of the first hole transport layer 1461 may range from 3 nm to 17 nm or from 5 nm to 10 nm.
  • the thickness h6 of the first hole transport layer 1461 may be 5 nm, 8 nm, 10 nm or 12 nm.
  • the thickness h7 of the second hole transport layer 1462 ranges from 10 nm to 50 nm.
  • the thickness h7 of the second hole transport layer 1462 may range from 15 nm to 45 nm or from 20 nm to 30 nm.
  • the thickness h7 of the second hole transport layer 1462 may be 20 nm, 25 nm, 30 nm, 35 nm or 45 nm.
  • the hole transport layer 146 is provided to include a first hole transport layer 1461 and a second hole transport layer 1462, and the material of the first hole transport layer 1461 includes TCTA, and the material of the second hole transport layer 1462 Including NPB can increase the number of holes in the first electrode 122 moving to the quantum dot light-emitting layer 126 and improve the luminous efficiency of the light-emitting device 110 .
  • the thickness h6 of the first hole transport layer 1461 is set to a value range of 2 nm to 20 nm
  • the thickness h7 of the second hole transport layer 1462 is set to a value range of 10 nm ⁇ 50 nm, thereby avoiding the need for the first hole transport layer 1461 Or the thickness of the second hole transport layer 1462 is too small (for example, the first hole transport layer 1461 is less than 2 nm, or the second hole transport layer 1462 is less than 10 nm), it can also avoid the first hole transport layer 1461 or the second hole transport layer 1462 being less than 10 nm.
  • the thickness of the hole transport layer 1462 is too large (for example, the first hole transport layer 1461 is greater than 20 nm, or the second hole transport layer 1462 is greater than 50 nm), which increases the difficulty of the first hole transport layer 1461 and the second hole transport layer 1462.
  • the hole transmission efficiency increases the number of holes in the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110.
  • display panel 100 further includes light coupling layer 148 .
  • the light coupling layer 148 is located on a side of the first electrode 122 away from the hole injection layer 144 .
  • the refractive index of the light coupling layer 148 is different from the refractive index of the first electrode 122 .
  • the refractive index of optical coupling layer 148 is greater than the refractive index of first electrode 122 .
  • the refractive index of the optical coupling layer 148 is set to be greater than the refractive index of the first electrode 122, so that the light passing through the first electrode 122 can irradiate into the optical coupling layer 148, And emit the light-emitting device 110 through the optical coupling layer 148 to avoid total reflection of light at the contact surface between the first electrode 122 and the optical coupling layer 148, thereby improving the light extraction rate of the light-emitting device 110, improving the light utilization rate, and increasing the size of the light-emitting device 110.
  • the material of the optical coupling layer 148 includes NPB (Chinese name: N,N′-di(naphthyl-1-yl)-N,N′-diphenyl-benzidine).
  • the thickness h9 of the optical coupling layer 148 ranges from 40 nm to 80 nm.
  • the thickness of the optical coupling layer 148 may range from 50 nm to 70 nm or from 55 nm to 65 nm.
  • the thickness of the optical coupling layer 148 may be 55 nm, 60 nm, 70 nm, or 75 nm.
  • the thickness h9 of the optical coupling layer 148 to a value range of 40 nm to 80 nm avoids the thickness of the optical coupling layer 148 being too small (for example, less than 40 nm) or too large (for example, more than 80 nm), and improves the efficiency of the light-emitting device 110
  • the light extraction rate increases the brightness of the light-emitting device 110 and reduces the power consumption of the display panel 100 .
  • the holes in the first electrode 122 and the electrons in the second electrode 124 are transported to the quantum dot light-emitting layer 126 and recombine in the quantum dot light-emitting layer 126 to emit light.
  • the mobility of electrons in the light-emitting device 110 is usually greater than the mobility of holes, resulting in unbalanced transport of electrons and holes, causing the number of electrons in the quantum dot light-emitting layer 126 to be greater than the number of holes.
  • the number of electrons in the quantum dot light-emitting layer 126 is greater than the number of holes, which will cause Auger recombination of electrons and holes in the quantum dot light-emitting layer 126 . That is, the electron and hole do not emit light after recombination, but transfer energy to another electron or hole through collision, causing the electron or hole to transition.
  • the luminous efficiency of the light-emitting device 110 is reduced; on the other hand, the Auger recombination generates heat, causing the temperature of the quantum dot luminescent layer 126 to rise, affecting the quantum
  • the lifespan of the point light-emitting layer 126 and other film layers adjacent to the quantum dot light-emitting layer 126 affects the service life of the light-emitting device 110.
  • any light-emitting device 110 further includes at least two electron transport layers 130 . At least two electron transport layers 130 are stacked and located between the second electrode 124 and the quantum dot light-emitting layer 126 .
  • At least two layers of electronic transport layers (English full name: Electronic Transport Layer, English abbreviation: ETL) 130 play a role in transmitting electrons. Therefore, at least two electron transport layers 130 are stacked between the second electrode 124 and the quantum dot light-emitting layer 126 so that electrons can be transported to the quantum dot light-emitting layer 126 through the at least two electron transport layers 130 .
  • the electron mobility or energy level of at least one electron transport layer 130 can be adjusted. This regulates the number of electrons transmitted to the quantum dot light-emitting layer 126, balances the mobility of electrons and holes in the light-emitting device 110, and improves the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126. , reducing the Auger recombination of electrons and holes in the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110 and extending the service life of the light-emitting device 110.
  • the plurality of light-emitting devices 110 include a first light-emitting device 112 and a second light-emitting device 114.
  • the first light-emitting device 112 is used to emit the first color light
  • the second light-emitting device 114 is used to emit the second color light.
  • the wavelength of the first color light is greater than the wavelength of the second color light.
  • the number of electron transport layers 130 in the first light-emitting device 112 is less than the number of electron transport layers 130 in the second light-emitting device 114 .
  • the number of electron transport layers 130 in the first light-emitting device 112 is set to be smaller than the number of electron transport layers 130 in the second light-emitting device 114 , that is, according to the light-emitting color (light-emitting wavelength) of the light-emitting device 110 , it is targeted Different numbers of electron transport layers 130 are provided.
  • the number of electrons in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be adjusted respectively, and the number of electrons and holes in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be increased in a targeted manner.
  • the consistency of the quantity can thereby improve the luminous efficiency of the light-emitting devices 110 of different colors in a targeted manner and extend the service life of the light-emitting devices 110 of different colors.
  • the display panel 100 also includes an electron injection layer (English full name: Electron Inject Layer, English abbreviation: EIL) 142.
  • the electron injection layer 142 is located between the second electrode 124 and the at least two electron transport layers 130 .
  • electron injection layer 142 is a ZnO (zinc oxide) film.
  • the light emitting device 110 may not include the electron injection layer 142 .
  • FIG. 3D is a structural diagram of a display panel according to further embodiments.
  • the sum h1 of the thicknesses of the at least two electron transport layers 130 in the first light-emitting device 112 is greater than the sum of the thicknesses h1 of the at least two electron transport layers 130 in the second light-emitting device 114 . and h2.
  • the sum h1 of the thicknesses of at least two electron transport layers 130 in the first light-emitting device 112 is the thickness of all electron transport layers 130 (two layers, three layers) in the first light-emitting device 112 or more layers).
  • the number of electrons transported to the quantum dot light-emitting layer 126 can be adjusted.
  • the sum h1 of the thickness of the at least two electron transport layers 130 in the first light-emitting device 112 is set to be greater than the sum h2 of the thickness of the at least two electron transport layers 130 in the second light-emitting device 114. That is, according to the luminescence
  • the emitting color (emitting wavelength) of the device 110 is specifically set to be different from the sum of the thicknesses of at least two electron transport layers 130 .
  • the number of electrons in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be adjusted respectively, and the number of electrons and holes in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be increased in a targeted manner.
  • the consistency of the quantity can thereby improve the luminous efficiency of the light-emitting devices 110 of different colors in a targeted manner and extend the service life of the light-emitting devices 110 of different colors.
  • FIG. 4 is a graph illustrating brightness of a light emitting device as a function of thickness of an electron transport layer, according to some embodiments.
  • the material of the second electrode 124 is ITO and the thickness is 70 nm.
  • the thickness of the quantum dot light-emitting layer 126 is 30 nm.
  • the material of the first hole transport layer 1461 is TCTA and the thickness is 10 nm.
  • the hole transport layer 1462 is made of NPB with a thickness of 30 nm, the hole injection layer 144 is made of MoO 3 with a thickness of 7 nm, and the first electrode 122 is made of Mg and Ag (the mass ratio of Mg to Ag is 2:8 ), the thickness is 10nm, and at least two electron transport layers 130 are both ZnO (zinc oxide) films.
  • the luminous brightness of the light-emitting device 110 (that is, the light intensity of the side of the light-emitting device 110 away from the driving backplane 150) varies with the The variation of the sum of the thicknesses of at least two electron transport layers 130 was simulated.
  • the abscissa is the sum of the thicknesses of at least two electron transport layers 130 in nm, and the ordinate is the luminance of the light-emitting device 110 in candelas per square meter (cd/m 2 ). .
  • the at least two electron transport layers 130 are ZnO films, the at least two electron transport layers 130 can be regarded as one electron transport layer 130 at this time.
  • curve a (shown as a dotted line) is the variation curve of the light intensity on the front side of the first light-emitting device 112 as a function of the sum of the thicknesses of at least two electron transport layers 130 (that is, the thickness of the ZnO film)
  • curve b ( Shown by the solid line) is the variation curve of the light intensity on the front side of the second light-emitting device 114 as a function of the sum of the thicknesses of at least two electron transport layers 130 (that is, the thickness of the ZnO film).
  • the change curves of the front light intensity with the sum of the thicknesses of at least two electron transport layers 130 are different.
  • curve a in FIG. 4 when the thickness of the ZnO film of the first light-emitting device 112 is about 45 nm or about 190 nm, the front light emitting intensity is relatively high.
  • curve b in FIG. 4 when the thickness of the ZnO film of the second light-emitting device 114 is about 20 nm or about 150 nm, the front light emission intensity is relatively high.
  • the thickness of the ZnO film that is, the sum of the thicknesses of at least two electron transport layers 130 .
  • the current efficiency luminous brightness/current density
  • the optical characteristics and electrical characteristics of the light-emitting device 110 it is necessary to combine the optical characteristics and electrical characteristics of the light-emitting device 110 to set a value range for the sum of the thicknesses of at least two electron transport layers 130 .
  • the sum of the thicknesses of at least two electron transport layers 130 ranges from 5 nm to 150 nm.
  • each electron transport layer 130 may be the same or different.
  • the sum of the thicknesses of at least two electron transport layers 130 ranges from 10 nm to 130 nm, 20 nm to 120 nm, 50 nm to 100 nm, etc.
  • the sum of the thicknesses of at least two electron transport layers 130 may be 20 nm, 50 nm, 70 nm, 90 nm or 130 nm.
  • the sum of the thicknesses of the at least two electron transport layers 130 is set to a value range of 5 nm to 150 nm, so as to avoid the sum of the thicknesses of the at least two electron transport layers 130 being too small (for example, less than 5 nm), resulting in the light emitting device 110 being damaged.
  • the current is too large and the current efficiency is reduced.
  • the thickness of the at least two electron transport layers 130 is too large (for example, greater than 150 nm), causing the turn-on voltage of the light-emitting device 110 to increase, the current to decrease, and the brightness to decrease, affecting the performance of the light-emitting device 110 .
  • the sum of the thicknesses of at least two electron transport layers 130 ranges from 20 nm to 70 nm.
  • the sum of the thicknesses of at least two electron transport layers 130 may range from 25 nm to 65 nm, 30 nm to 60 nm, 40 nm to 55 nm, or 45 nm to 50 nm.
  • the thickness of the at least two electron transport layers 130 may be 35 nm, 45 nm, 55 nm or 65 nm.
  • the value range of the sum of the thicknesses of the at least two electron transport layers 130 is set to be in the range of 20 nm to 70 nm, so as to avoid the sum of the thicknesses of the at least two electron transport layers 130 being too small (for example, less than 20 nm), causing the light emitting device 110 to The current is too large and the current efficiency is reduced. Moreover, it can also be avoided that the thickness of the at least two electron transport layers 130 is too large (for example, greater than 70 nm), causing the turn-on voltage of the light-emitting device 110 to increase, the current to decrease, and the brightness to decrease, thereby affecting the performance of the light-emitting device 110 .
  • setting the sum of the thicknesses of at least two electron transport layers 130 in a range of 20 nm to 70 nm can improve the luminous efficiency of the light emitting device 110 by integrating the optical properties and electrical properties of the light emitting device 110 .
  • the sum of the thicknesses of at least two electron transport layers 130 ranges from 20 nm to 60 nm.
  • the sum of the thicknesses of at least two electron transport layers 130 may range from 25 nm to 55 nm, from 30 nm to 50 nm, or from 35 nm to 45 nm.
  • the thickness of the at least two electron transport layers 130 may be 22 nm, 30 nm, 35 nm, 45 nm or 55 nm.
  • the value range of the sum of the thicknesses of the at least two electron transport layers 130 is set to be in the range of 20 nm to 60 nm, so as to avoid the sum of the thicknesses of the at least two electron transport layers 130 being too small (for example, less than 20 nm), causing the light emitting device 110 to The current is too large and the current efficiency is reduced. Moreover, it can also be avoided that the thickness of the at least two electron transport layers 130 is too large (for example, greater than 60 nm), causing the turn-on voltage of the light-emitting device 110 to increase, the current to decrease, and the brightness to decrease, thereby affecting the performance of the light-emitting device 110 .
  • setting the sum of the thicknesses of at least two electron transport layers 130 in a range of 20 nm to 60 nm can combine the optical and electrical characteristics of the light-emitting device 110 to improve the luminous efficiency of the light-emitting device 110 .
  • the display panel 100 further includes a driving backplane 150 , and the plurality of light-emitting devices 110 are located on one side of the driving backplane 150 . Furthermore, the light-emitting device 110 has an inverted structure, that is, the first electrode 122 is farther away from the driving backplane 150 than the second electrode 124 .
  • FIG. 5A is a structural diagram of a display panel according to further embodiments.
  • the first light emitting device 112 includes a first portion of the first electrode 122a
  • the second light emitting device 114 includes a second portion of the first electrode 122b.
  • the distance d1 between the surface of the first part of the first electrode 122 a away from the driving back plate 150 and the driving back plate 150 is greater than the distance d1 between the surface of the second part of the first electrode 122 b away from the driving back plate 150 and the driving back plate 150 The distance d2.
  • the first electrodes 122 of the plurality of light-emitting devices 110 (including the first light-emitting devices 112 and the second light-emitting devices 114) have a whole-layer structure.
  • the first part of the first electrode 122a and the second part of the first electrode 122b are part of the entire layer of the first electrode 122.
  • the third The distance d1 between the surface of a part of the first electrode 122 a away from the driving back plate 150 and the driving back plate 150 can be greater than the distance d1 between the surface of the second part of the first electrode 122 b far away from the driving back plate 150 and the driving back plate 150 The distance d2.
  • the distance d1 between the surface of the first part of the first electrode 122a away from the driving back plate 150 and the driving back plate 150 is, that is, The distance between the surface of the first part of the first electrode 122a that is far away from the driving back plate 150 and the film layer of the driving back plate 150 that is farthest from the substrate 152 (for example, the driving circuit layer 158).
  • Such arrangement can improve the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors, so that the first electrode 122 (for example, the first part of the first electrode) in the different light-emitting devices 110
  • the thickness of the first electrode 122a and the second part of the first electrode 122b) can be the same or approximately the same, that is, the thickness of the entire first electrode 122 at different positions can be the same or approximately the same, which improves the sensitivity of the first electrode 122 to different light-emitting devices.
  • the quantum dot light-emitting layer 126 in 110 transmits a consistent number of holes, thereby improving the reliability of multiple light-emitting devices 110 .
  • the first light-emitting device 112 when the light-emitting device 110 is in an upright structure, that is, when the first electrode 122 is close to the driving backplane 150 relative to the second electrode 124, similarly, the first light-emitting device 112 includes a first portion.
  • the second electrode, the second light-emitting device 114 includes a second part of the second electrode, and the distance between the surface of the first part of the second electrode away from the driving backplane 150 and the driving backplane 150 is greater than the second part of the second electrode away from the driving backplane 150 .
  • FIG. 5B is a structural diagram of a display panel according to further embodiments.
  • the display panel 100 further includes a filling layer 128 .
  • the filling layer 128 is located at least on a side surface of the second portion of the first electrode 122b away from the driving backplane 150 . Furthermore, the surface of the filling layer 128 on the side away from the driving back plate 150 is flush or nearly flush with the surface on the side of the first part of the first electrode 122 a away from the driving back plate 150 , thereby improving the structural regularity of the light emitting device 110 .
  • the material of the filling layer 128 includes silicon oxide, silicon nitride, or the like.
  • Figure 6 is a structural diagram of a first light emitting device according to some embodiments.
  • At least two electron transport layers 130 in the first light emitting device 112 include a first electron transport layer 131 and a second electron transport layer 132 .
  • the electron mobility of the second electron transport layer 132 is smaller than the electron mobility of the first electron transport layer 131 .
  • the first electron transport layer 131 is closer to the second electrode 124 relative to the second electron transport layer 132 . In other examples, the first electron transport layer 131 is further away from the second electrode 124 relative to the second electron transport layer 132 .
  • setting the electron mobility of the second electron transport layer 132 to be lower than the electron mobility of the first electron transport layer 131 can reduce the overall electron mobility of at least two electron transport layers 130 and reduce the quantum dot light-emitting layer 126
  • the number of electrons in the quantum dot light-emitting layer 126 improves the consistency of the number of electrons and holes, and improves the luminous efficiency of the light-emitting device 110 .
  • Figure 7A is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to some embodiments.
  • FIG. 7B is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to other embodiments.
  • FIG. 7C is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to further embodiments.
  • FIG. 7D is an energy level relationship diagram of the first electron transport layer and the second electron transport layer according to further embodiments.
  • the conduction band bottom energy level CBM1 (English full name: Conduction Band Minimum, English abbreviation: CBM) of the first electron transport layer 131 is different from the conduction band bottom level of the second electron transport layer 131 .
  • the bottom energy level CBM2 is different.
  • Such an arrangement can form an electron transmission barrier between the first electron transport layer 131 and the second electron transport layer 132, hindering the transmission of electrons to the quantum dot luminescent layer 126, reducing the number of electrons in the quantum dot luminescent layer 126, and improving the quantum dot luminescent layer 126.
  • the number of electrons and holes in the point light-emitting layer 126 is consistent, thereby improving the luminous efficiency of the light-emitting device 110 .
  • first electron transport layer 131 is closer to second electrode 124 relative to second electron transport layer 132. At this time, the conduction band bottom energy level CBM1 of the first electron transport layer 131 is smaller than the conduction band bottom energy level CBM2 of the second electron transport layer 132 .
  • the conduction band bottom energy level CBM1 of the first electron transport layer 131 is less than
  • the conduction band bottom energy level CBM2 of the second electron transport layer 132 can form an electron transport barrier between the first electron transport layer 131 and the second electron transport layer 132, hindering the transmission of electrons to the quantum dot light-emitting layer 126, reducing quantum
  • the number of electrons in the point light-emitting layer 126 improves the consistency of the number of electrons and the number of holes in the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110.
  • the valence band top energy level VBM1 (English full name: Valance Band Maximum, English abbreviation: VBM) of the first electron transport layer 131 is greater than the valence band top energy of the second electron transport layer 132 Level VBM2.
  • the valence band top energy level VBM1 of the first electron transport layer 131 is smaller than the valence band top energy level VBM2 of the second electron transport layer 132 .
  • the first electron transport layer 131 is further away from the second electrode 124 relative to the second electron transport layer 132 . At this time, the conduction band bottom energy level CBM1 of the first electron transport layer 131 is greater than the conduction band bottom energy level CBM2 of the second electron transport layer 132 .
  • the conduction band bottom energy level CBM1 of the first electron transport layer 131 is greater than The conduction band bottom energy level CBM2 of the second electron transport layer 132 can form an electron transport barrier between the first electron transport layer 131 and the second electron transport layer 132, hindering the transmission of electrons to the quantum dot light-emitting layer 126, and improving the quantum The number of electrons and holes in the point light-emitting layer 126 is consistent, thereby improving the luminous efficiency of the light-emitting device 110 .
  • the valence band top energy level VBM1 of the first electron transport layer 131 is greater than the valence band top energy level VBM2 of the second electron transport layer 132 .
  • the valence band top energy level VBM1 of the first electron transport layer 131 is smaller than the valence band top energy level VBM2 of the second electron transport layer 132 .
  • Figure 8 is an energy level structure diagram of a light emitting device according to some embodiments.
  • the direction of arrow g is the direction in which energy levels (including the top energy level VBM of the valence band and the bottom energy level CBM of the conduction band) increase.
  • Arrow e - represents the migration path of electrons
  • arrow h + represents the migration path of holes.
  • the material of the second electrode 124 of the first light-emitting device 112 is ITO, and the conduction band bottom energy level CBM6 is -4.7eV (English full name: electron volt, Chinese name: electron volt).
  • the first electron transport layer 131 is a ZnO film, the conduction band bottom energy level CBM1 is -4.1eV, and the valence band top energy level VBM1 is -7.3eV.
  • the second electron transport layer 132 is a ZnMgO (magnesium zinc oxide) film, the conduction band bottom energy level CBM2 is -3.9eV, and the valence band top energy level VBM2 is -7.4eV.
  • the material of the red quantum dot light-emitting layer (English full name: Red Quantum Dot, English abbreviation: RQD) is CdSe series quantum dot material, the conduction band bottom energy level CBM7 is -4.0eV, and the valence band top energy level VBM7 is -6.0eV.
  • the first hole transport layer 1461 is a TCTA film, the conduction band bottom energy level CBM8 is -2.3eV, and the valence band top energy level VBM8 is -5.7eV.
  • the second hole transport layer 1462 is an NPB film, the conduction band bottom energy level CBM9 is -2.4eV, and the valence band top energy level VBM9 is -5.4eV.
  • the hole injection layer 144 is a MoO 3 film, the conduction band bottom energy level CBM10 is -6.0eV, and the valence band top energy level VBM10 is -9.0eV.
  • the materials of the first electrode 122 are Mg and Ag (the mass ratio of Mg and Ag is 2:8), and the conduction band bottom energy level CBM11 is -4.1 eV.
  • the material of the first electron transport layer 131 includes ZnO (zinc oxide), GZO (gallium zinc oxide), AZO (aluminum zinc oxide), IZO (indium zinc oxide), IGZO (indium gallium zinc oxide), and Any one of ZnMgO (magnesium zinc oxide)
  • the material of the second electron transport layer 132 includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO, and the material of the first electron transport layer 131 and the second electron transport layer The material of layer 131 is different.
  • This arrangement enables the electron mobility of the second electron transport layer 132 to be smaller than the electron mobility of the first electron transport layer 131 and allows an electron transport barrier to be formed between the first electron transport layer 131 and the second electron transport layer 132 , hindering the transmission of electrons to the quantum dot light-emitting layer 126, improving the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110.
  • first electron transport layer 131 and the second electron transport layer 132 can also be other n-type oxide films.
  • the material of the first electron transport layer 131 when the first electron transport layer 131 is close to the quantum dot light-emitting layer 126 relative to the second electron transport layer 132, the material of the first electron transport layer 131 includes ZnO, and the material of the second electron transport layer includes ZnMgO.
  • the sum of the thicknesses of at least two electron transport layers 130 affects the number of electrons in the quantum dot light-emitting layer 126 . It can be understood that the thickness of each of the at least two electron transport layers 130 will affect the number of electrons in the quantum dot light-emitting layer 126 .
  • the thickness h1 of the first electron transport layer 131 is greater than 0 nm and less than or equal to 60 nm. And/or, the thickness h2 of the second electron transport layer 132 is greater than 0 nm and less than or equal to 60 nm. Furthermore, the thickness h1 of the first electron transport layer 131 is greater than the thickness h2 of the second electron transport layer 132 .
  • the thickness h1 of the first electron transport layer 131 is greater than 0 nm and less than or equal to 55 nm. In other examples, the thickness h1 of the first electron transport layer 131 is greater than 0 nm and less than or equal to 45 nm. In some further examples, the thickness h1 of the first electron transport layer 131 is greater than 0 nm and less than or equal to 35 nm.
  • the thickness h1 of the first electron transport layer 131 may be 15 nm, 25 nm, 35 nm or 45 nm, etc.
  • the thickness h2 of the second electron transport layer 132 is greater than 0 nm and less than or equal to 55 nm. In other examples, the thickness h2 of the second electron transport layer 132 is greater than 0 nm and less than or equal to 45 nm. In some further examples, the thickness h2 of the second electron transport layer 132 is greater than 0 nm and less than or equal to 35 nm.
  • the thickness h2 of the second electron transport layer 132 may be 15 nm, 25 nm, 35 nm or 45 nm, etc.
  • the thickness h1 of the first electron transport layer 131 is set to be greater than 0 nm and less than or equal to 60 nm, and the thickness h2 of the second electron transport layer 132 is greater than 0 nm and less than or equal to 60 nm, thereby avoiding the need for the first electron transport layer 131 and the second electron transport layer
  • the thickness of the layer 132 is too large (for example, the first electron transport layer 131 or the second electron transport layer 132 is greater than 60 nm), causing the turn-on voltage of the first light-emitting device 112 to increase, the current to decrease, and the brightness to decrease, affecting the first light-emitting device 112 performance.
  • the thickness of the first electron transport layer 131 and the second electron transport layer 132 being too large (for example, the thickness of the first electron transport layer 131 or the second electron transport layer 132 is greater than 60 nm), and also increase the front surface of the first light-emitting device 112 (away from the driving backplane 150) light intensity, reducing the side light intensity of the first light-emitting device 112, increasing the light extraction rate of the first light-emitting device 112, increasing the brightness of the first light-emitting device 112, and reducing the power consumption of the display panel 100.
  • the thickness h1 of the first electron transport layer 131 can prevent the sum h of the thickness of at least two electron transport layers 130 from being too large, causing the first light-emitting device 112 to turn on.
  • the voltage increases, the current decreases, and the brightness decreases, affecting the performance of the first light-emitting device 112 .
  • the thickness of the first electron transport layer 131 ranges from 30 nm to 50 nm.
  • the thickness of the second electron transport layer 132 ranges from 1 nm to 30 nm.
  • the thickness h1 of the first electron transport layer 131 may range from 35 nm to 45 nm or from 30 nm to 40 nm.
  • the thickness h1 of the first electron transport layer 131 may be 35 nm, 40 nm, or 45 nm.
  • the thickness h2 of the second electron transport layer 132 may range from 5 nm to 25 nm or from 10 nm to 20 nm.
  • the thickness h2 of the second electron transport layer 132 may be 5 nm, 10 nm, 15 nm or 20 nm, etc.
  • the thickness h1 of the first electron transport layer 131 is set to a value range of 30 nm to 50 nm, and the thickness of the second electron transport layer 132 is set to a value range of 1 nm ⁇ 30 nm, thereby avoiding the need for the thickness h1 of the first electron transport layer 131 or the second
  • the thickness h2 of the electron transport layer 132 is too small (for example, the thickness h1 of the first electron transport layer 131 is less than 30 nm, and the thickness of the second electron transport layer 132 is less than 1 nm), resulting in excessive current in the first light-emitting device 112 and reduced current efficiency.
  • the thickness h1 of the first electron transport layer 131 or the thickness h2 of the second electron transport layer 132 is too large (for example, the thickness h1 of the first electron transport layer 131 is greater than 50 nm, and the thickness of the second electron transport layer 132 is greater than 30 nm. ), causing the turn-on voltage of the first light-emitting device 112 to increase, the current to decrease, and the brightness to decrease, affecting the performance of the first light-emitting device 112.
  • the thickness h1 of the first electron transport layer 131 or the thickness h2 of the second electron transport layer 132 being too large (for example, the thickness h1 of the first electron transport layer 131 is greater than 50 nm, and the thickness of the second electron transport layer 132 is greater than 30 nm), It can also increase the light intensity of the front side of the first light-emitting device 112 (away from the driving backplane 150 ), reduce the side light intensity of the first light-emitting device 112 , increase the light extraction rate of the first light-emitting device 112 , and increase the light intensity of the first light-emitting device 112 . brightness and reduce the power consumption of the display panel by 100%.
  • Figure 9A is a graph of current density as a function of voltage according to some embodiments.
  • Figure 9B is a graph of luminescence brightness as a function of voltage according to some embodiments.
  • Figure 9C is a graph of external quantum efficiency as a function of voltage according to some embodiments.
  • the current density and luminous brightness of the first light emitting device 112 are and external quantum efficiency are given as examples.
  • the abscissa represents voltage (unit V), and the ordinate represents current density (unit: milliampere/square centimeter, mA/cm 2 ).
  • the abscissa is voltage (unit V), and the ordinate is luminous brightness (unit is candela per square meter cd/m 2 ).
  • combinations 1 to 4 are combinations of electron transport layers 130 with different thicknesses and materials.
  • the material of at least two electron transport layers 130 in combination 1 is ZnO (which can also be regarded as one electron transport layer 130), and the thickness of the ZnO film is 60 nm.
  • the material of the first electron transport layer 131 in combination 2 is ZnO, and the thickness is 45 nm.
  • the material of the second electron transport layer 132 is ZnMgO, and the thickness is 15nm.
  • the material of the first electron transport layer 131 in combination 3 is ZnO, and the thickness is 30 nm.
  • the material of the second electron transport layer 132 is ZnMgO, and the thickness is 30 nm.
  • the material of the first electron transport layer 131 in combination 4 is ZnMgO, and the thickness is 15 nm.
  • the material of the second electron transport layer 132 is ZnO, and the thickness is 45 nm.
  • the molar percentage of Mg in ZnMgO is 5%.
  • the first light-emitting device 112 uses a double-layer electron transport layer 130 (including the first electron transport layer 131 and the second electron transport layer 132 , such as combination 2, combination 3 and combination 4),
  • the current density, luminous brightness and EQE are all better than the single-layer electron transport layer 130 (combination 1). That is, when the double-layer electron transport layer 130 is selected, the first light-emitting device 112 can have better luminescence performance.
  • At least one of the first electron transport layer 131 and the second electron transport layer 132 is made of ZnMgO, which can block electrons through Mg ion doping. Reduce the electron mobility of the first electron transport layer 131 or the second electron transport layer 132, thereby reducing the number of electrons in the quantum dot light-emitting layer 126, and improving the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, thereby The luminous efficiency of the first light-emitting device 112 is improved.
  • the material of the first electron transport layer 131 is ZnO and the material of the second electron transport layer 132 is ZnMgO
  • an energy level difference can be formed between the first electron transport layer 131 and the second electron transport layer 132, thereby forming electrons.
  • the transmission barrier hinders the transmission of electrons to the quantum dot light-emitting layer 126 and balances the electron transmission ability and the hole transmission ability in the first light-emitting device 112, thereby improving the luminous efficiency of the first light-emitting device 112.
  • the first light-emitting device 112 of combination 3 when the voltage increases, the first light-emitting device 112 of combination 3 is selected to emit smaller brightness and lower current density, resulting in lower current efficiency, and, as shown in FIG. 9C , the selected first light-emitting device 112 In combination 3, the external quantum efficiency EQE of the first light-emitting device 112 is small, which affects the performance of the first light-emitting device 112 .
  • the thickness of the ZnMgO film is increased from 20 nm to 40 nm, the current of the first light-emitting device 112 decreases, the luminous brightness also decreases, and the performance of the first light-emitting device 112 is lower than that of combination 2 (material of the first electron transport layer 131 is ZnO with a thickness of 45 nm, and the material of the second electron transport layer 132 is ZnMgO with a thickness of 15 nm).
  • the thickness of the first electron transport layer 131 is approximately 45 nm. And/or, the thickness of the second electron transport layer 132 is approximately 15 nm.
  • the thickness of the first electron transport layer 131 is approximately 45 nm, that is, the thickness of the first electron transport layer 131 is 45 nm, and can accept a certain range on the basis of 45 nm. Deviation within (for example, within 3% or within 5%, etc.).
  • the material of the second electron transport layer 132 includes ZnMgO.
  • the mole percentage of Mg in the second electron transport layer 132 is greater than 0 and less than or equal to 50%.
  • the sum of the mole percentages of Mg and Zn is 1.
  • the material of the second electron transport layer 132 includes Zn 1-X Mg X O, where X is the mole percentage of Mg, and 1-X is the mole percentage of Zn.
  • the mole percentage of Mg in the second electron transport layer 132, the electron mobility of the second electron transport layer 132, and the energy level of the second electron transport layer 132 plays a regulating role, thereby regulating the number of electrons transmitted to the quantum dot light-emitting layer 126, improving the transmission balance of electrons and holes in the first light-emitting device 112, thereby improving the first The luminous efficiency of the light-emitting device 112.
  • the mole percent of Mg can be greater than 0 and less than or equal to 40%. In other examples, the mole percent of Mg may be greater than 0 and less than or equal to 30%. In still other examples, the mole percent of Mg may be greater than 0 and less than or equal to 20%.
  • the molar percentage of Mg in the second electron transport layer 132 may be 10%, 20%, 30% or 40%.
  • the molar percentage of Mg in the second electron transport layer 132 is greater than 0 and less than or equal to 50%, the molar percentage of Zn is greater than or equal to 50% and less than 100%.
  • the molar percentage of Mg in the second electron transport layer 132 ranges from 1% to 20%.
  • the molar percentage of Mg in the second electron transport layer 132 may range from 2% to 20%, 5% to 15%, or 7% to 12%.
  • the mole percentage of Mg in the second electron transport layer 132 may be 5%, 8%, 10% or 15%.
  • the mole percentage of Mg in the second electron transport layer 132, the electron mobility of the second electron transport layer 132, and the energy level of the second electron transport layer 132 plays a regulating role, thereby regulating the number of electrons transmitted to the quantum dot light-emitting layer 126, improving the transmission balance of electrons and holes in the first light-emitting device 112, thereby improving the first The luminous efficiency of the light-emitting device 112.
  • Figure 10A is a graph of current density as a function of voltage according to other embodiments.
  • FIG. 10B is a graph of changes in luminous brightness with voltage according to other embodiments.
  • FIG. 10C is a graph of external quantum efficiency as a function of voltage according to other embodiments.
  • the abscissa represents voltage (unit V), and the ordinate represents current density (unit: milliampere/square centimeter, mA/cm 2 ).
  • the abscissa represents voltage (unit V), and the ordinate represents luminous brightness (unit: candela per square meter cd/m 2 ).
  • combinations 5 to 7 are combinations of the second electron transport layer 132 and the first electron transport layer 131 when the molar percentage of Mg in the second electron transport layer 132 is different.
  • At least two electron transport layers 130 in combination 5 are ZnO (can also be regarded as one electron transport layer 130) thin films, and the thickness of the ZnO thin films is 60 nm.
  • the first electron transport layer 131 is a ZnO film with a thickness of 45 nm.
  • the second electron transport layer 132 is a ZnMgO film with a thickness of 15 nm, in which the molar percentage of Mg in ZnMgO is 5%.
  • the first electron transport layer 131 is a ZnO film with a thickness of 45 nm.
  • the second electron transport layer 132 is a ZnMgO film with a thickness of 15 nm, in which the molar percentage of Mg in ZnMgO is 8%.
  • the first light-emitting device 112 uses a double-layer electron transport layer 130 (including the first electron transport layer 131 and the second electron transport layer 132 , such as combination 6 and combination 7), the current density, The luminous brightness and EQE are both better than the single-layer electron transport layer 130 (combination 5). That is, when the double-layer electron transport layer 130 is selected, the first light-emitting device 112 can have better luminescence performance.
  • the first light-emitting device 112 of combination 7 when the voltage increases, the first light-emitting device 112 of combination 7 is selected to emit light with smaller brightness and a smaller current density, resulting in smaller current efficiency, and, as shown in FIG. 10C , the selected first light-emitting device 112 In combination 7, the EQE of the first light-emitting device 112 is small, which affects the performance of the first light-emitting device 112.
  • the first The light-emitting device 112 has better light-emitting performance.
  • the molar percentage of Mg in the second electron transport layer 132 is approximately 5%.
  • the mole percentage of Mg in the second electron transport layer 132 is approximately 5%, that is, the mole percentage of Mg in the second electron transport layer 132 is The molar percentage is 5%, and the deviation within a certain range (such as within 3% or within 5%, etc.) can be accepted on the basis of 5%.
  • the first electron transport layer 131 is a ZnO film with a thickness of 45 nm
  • the second electron transport layer 132 is a ZnMgO film with a thickness of 15 nm, where the molar percentage of Mg in ZnMgO is 5%
  • the first electron transport layer 132 is a ZnMgO film with a thickness of 15 nm.
  • the energy level relationship diagram of the transport layer 131 and the second electron transport layer 132 is shown in FIG. 7A.
  • the first electron transport layer 131 is a ZnMgO film with a thickness of 15 nm, and the molar percentage of Mg in ZnMgO is 5%
  • the first electron transport layer The energy level relationship diagram between 131 and the second electron transport layer 132 is shown in Figure 7D.
  • the preparation method of the light emitting device 110 is illustrated below with an example.
  • At least two electron transport layers 130 are formed on one side of the second electrode 124 using a solution method.
  • at least two electron transport layers 130 are formed using a solution method, that is, the particles forming the electron transport layer 130 are dissolved in a solvent, and then the solvent is evaporated.
  • the ZnO particles can be dissolved in ethanol, and the solvent obtained after dissolving is coated (for example, by inkjet printing, etc.) on one side of the second electrode 124, and The ethanol evaporates and a ZnO film is obtained.
  • the ZnO thin film prepared by the solvent method there are a large number of surface states of ZnO nanoparticles (that is, there are a large number of defects on the surface of ZnO nanoparticles).
  • a large number of surface states present in the ZnO nanoparticles interact with the quantum dot light-emitting layer 126 to capture electrons in the quantum dot light-emitting layer 126 and affect the luminous efficiency of the light-emitting device 110 .
  • Electron transport layer 130 when at least two electron transport layers 130 need to be formed, it is necessary to continue to coat a solvent on the side of the electron transport layer 130 away from the second electrode 124 after forming one electron transport layer 130 to form another layer. Electron transport layer 130.
  • the electron transport layer 130 formed first is defined as the first electron transport layer below, and the electron transport layer 130 formed later is defined as the second electron transport layer. It should be noted that the first electron transport layer and the second electron transport layer are only used to distinguish the electron transport layer 130 formed earlier and the electron transport layer 130 formed later, and the electron transport layer 130 is not further limited.
  • the solvent forming the second electron transport layer needs to be coated on the side of the formed first electron transport layer away from the second electrode 124. In this way, When the solvent forming the second electron transport layer and the solvent forming the first electron transport layer are non-orthogonal solvents, the solvent forming the second electron transport layer will dissolve the already formed first electron transport layer again. The formed first electron transport layer is damaged, which increases the difficulty of producing at least two electron transport layers 130 .
  • ZnO is in the form of nanoparticles.
  • the diameter of ZnO nanoparticles is approximately 5 nm.
  • the surface roughness (English full name: Surface Roughness) of the ZnO film will be high.
  • the RMS (English full name: Root Mean Square, Chinese name: Root Mean Square) surface roughness of ZnO films prepared by solvent method can reach 1nm ⁇ 2nm.
  • the ZnO film prepared by the solvent method cannot be adapted to high-resolution display, which affects the display performance of the display panel 100 .
  • a magnetron sputtering process is used to form at least two electron transport layers 130 on one side of the second electrode 124 .
  • the second electrode 124 as an ITO substrate as an example, a method for preparing at least two electron transport layers 130 will be described below.
  • the first electron transport layer 131 may be formed by single target sputtering.
  • the first electron transport layer 131 is a ZnO film.
  • the cleaned ITO substrate is introduced into the magnetron sputtering chamber.
  • argon gas is introduced.
  • the flow rate of argon gas is 30 sccm ⁇ 60 sccm (English full name: Stard Liter Per Minute , Chinese name: standard liter/minute), for example, the flow rate of argon gas can be 40sccm ⁇ 50sccm.
  • the chamber air pressure can be in the range of 0.5Pa ⁇ 0.6Pa.
  • the power of the radio frequency source is set to 20W ⁇ 150W.
  • the power of the radio frequency source can be 50W ⁇ 100W.
  • the baffle is opened to deposit the target target material on the ITO substrate.
  • the set process time is over, the sputtering is stopped, and the ITO substrate is taken out of the process chamber, so that a ZnO film can be deposited on the ITO substrate as the first electron transport layer 131.
  • the second electron transport layer 132 may be formed using multi-target sputtering.
  • the second electron transport layer 132 is a MgZnO film.
  • argon gas begins to be introduced.
  • the flow rate of argon gas is 30 sccm to 60 sccm (English full name :Stard Liter Per Minute, Chinese name: Standard Liter Per Minute), for example, the flow rate of argon gas can be 40sccm ⁇ 50sccm.
  • the chamber air pressure can be in the range of 0.5Pa ⁇ 0.6Pa.
  • the power of the first RF source is set to 20W ⁇ 150W.
  • the power of the first RF source can be 50W ⁇ 100W.
  • the power of the second RF source is set to 20W ⁇ 150W.
  • the power of the second RF source can be 50W ⁇ 100W.
  • the target baffles of the first RF source and the second RF source are opened to deposit the target target material on the ITO substrate.
  • the first radio frequency source can be used to sputter ZnO
  • the second radio frequency source can be used to sputter MgO, so that Mg ions and Zn ions can be deposited on the ITO substrate to form an MgZnO film.
  • the sputtering is stopped, and the ITO substrate is taken out of the process chamber, so that an MgZnO film can be deposited on the ITO substrate as the second electron transport layer 132 .
  • the second electron transport layer 132 may be deposited on a side of the first electron transport layer 131 away from the second electrode 124 .
  • the thickness of the film deposited on the ITO substrate can be controlled.
  • the longer the sputtering process time the thicker the film thickness.
  • the higher the sputtering power and the stronger the Ar ion bombardment the size of the particles (such as ZnO nanoparticles or MgZnO nanoparticles) in the film increases, and the film deposition rate increases.
  • the sputtering pressure increases, the atomic free path decreases, the Ar ion energy weakens, and the bombardment becomes weaker, resulting in a decrease in film crystallinity and a decrease in growth rate.
  • magnetron sputtering to form at least two layers of electron transport layer 130 can, on the one hand, reduce the surface state of the oxide (such as ZnO) in the electron transport layer 130, thereby reducing the surface state of the electron transport layer 130.
  • the interaction between the oxide and the quantum dot light-emitting layer 126 is beneficial to reducing non-radiative recombination (such as Auger recombination) losses caused by interface defects and improving the luminous efficiency of the light-emitting device 110 .
  • the impact of the later-formed electron transport layer 130 on the previously formed electron transport layer 130 can be reduced, and the previously formed electron transport layer 130 is not easily damaged, so that at least two electron transport layers can be flexibly controlled. 130 thickness and material, etc., thereby being able to flexibly control the optical properties and electrical properties of the first light-emitting device 112, improve the consistency of electron mobility and hole mobility in the first light-emitting device 112, and balance the electron mobility in the first light-emitting device 112 and hole transport capabilities, thereby improving the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, and improving the luminous efficiency of the first light-emitting device 112.
  • the ZnO film formed by the magnetron sputtering process in the ZnO film formed by the magnetron sputtering process, the ZnO will not be in the form of nanoparticles or only a small amount, thereby reducing the surface of the ZnO film. Roughness.
  • the RMS surface roughness of a ZnO film formed by a magnetron sputtering process can be reduced to about 0.5 nm, thereby improving the luminescence performance of the light-emitting device 110 .
  • using a magnetron sputtering process to form at least two layers of electron transport layers 130 can also match high-resolution displays, and the process is simple and can be adapted to the preparation process of the driving backplane 150 to improve the display performance of the display panel 100 , reducing the production cost of the display panel 100 .
  • the magnetron sputtering process can be used to form the electron transport layer 130 on the ITO substrate.
  • the power of the first radio frequency source when forming the stacked double-layer electron transport layer 130 (including the first electron transport layer 131 and the second electron transport layer 132), can be set to 20W to 150W.
  • the power of the first RF source can be 50W ⁇ 100W.
  • the power of the second RF source can be set to 20W ⁇ 150W.
  • the power of the second RF source can be 50W ⁇ 100W.
  • the target shutter of the first RF source is opened to deposit the first electron transport layer 131 on the ITO substrate.
  • a first RF source can be used to sputter ZnO.
  • the target baffle of the second RF source is opened, and the first RF source and the second RF source are co-sputtering, so that the second electron transport layer 132 is deposited on the first electron transport layer 131 away from the ITO.
  • One side of the substrate that is, the second electrode 124).
  • the second radio frequency source can be used to sputter MgO, and the first radio frequency source and the second radio frequency source are co-sputtering, so that Mg ions and Zn ions can be deposited on the ITO substrate to form an MgZnO film. After 5 to 15 minutes, stop sputtering. The ITO substrate after depositing at least two electron transport layers 130 is taken out of the process chamber.
  • spin coating can be used to coat the side of the second electron transport layer 132 away from the first electron transport layer 131 with red CdSe system quantum particles. Dot the solution. Then bake it on a heating platform or oven.
  • the baking temperature range is 80°C ⁇ 150°C, and the baking time is 5 minutes ⁇ 30 minutes.
  • the temperature of the heating platform can be controlled to 120° C. and baked for 10 minutes to form the quantum dot light-emitting layer 126 on the side of at least two electron transport layers 130 away from the second electrode 124 .
  • second electrode 124 At least two electron transport layers 130 and quantum dot light-emitting layer 1266 into an evaporation machine at a temperature of 5 ⁇ 10 -4 Pa to 4 ⁇ 10 -5 Pa.
  • the hole transport layer 146, the hole injection layer 144 and the first electrode 122 are thermally evaporated and deposited.
  • a glass plate can be used to cover the first electrode 122, and an encapsulant is placed between the first electrode 122 and the glass plate, and the encapsulation is cured by ultraviolet irradiation to provide protection.
  • the role of the light-emitting device 110 the first light-emitting device 112).
  • the display panel 100 further includes a third light-emitting device 116 .
  • the third light emitting device 116 is used to emit third color light.
  • the wavelength of the second color light is greater than the wavelength of the third color light.
  • the third color light is blue light (wavelength is about 400nm ⁇ 470nm).
  • the size of the quantum dot core of the quantum dot 1261 in the second light emitting device 114 is larger than the size of the quantum dot core of the quantum dot 1261 in the third light emitting device 116 .
  • the first light-emitting device 112, the second light-emitting device 114, and the third light-emitting device 116 By adjusting the size of the quantum dot cores in the quantum dots 1261 in different light-emitting devices 110 (the first light-emitting device 112, the second light-emitting device 114, and the third light-emitting device 116), the first light-emitting device 112, the second light-emitting device 114 The third light-emitting device 116 can emit light of different colors, so that the display panel 100 can realize full-color image display.
  • the number of electron transport layers in the first light emitting device 112 is less than the number of electron transport layers in the third light emitting device 116 .
  • the number of electron transport layers 130 in the first light-emitting device 112 is set to be smaller than the number of electron transport layers 130 in the third light-emitting device 116 , that is, according to the light-emitting color (light-emitting wavelength) of the light-emitting device 110 , it is targeted Different numbers of electron transport layers 130 are provided.
  • the number of electrons in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be adjusted respectively, and the number of electrons and holes in the quantum dot light-emitting layer 126 in the light-emitting devices 110 of different colors can be increased in a targeted manner.
  • the consistency of the quantity can thereby improve the luminous efficiency of the light-emitting devices 110 of different colors in a targeted manner and extend the service life of the light-emitting devices 110 of different colors.
  • the number of electron transport layers 130 in the first light-emitting device 112 is smaller than the number of electron transport layers 130 in the second light-emitting device 114 .
  • the number of electron transport layers 130 in the second light-emitting device 114 is equal to the number of electron transport layers in the third light-emitting device 116 .
  • the second electrode 124 is farther away from the driving backplane 150 than the first electrode 122 .
  • the third light emitting device 116 includes a third portion of the first electrode 122c.
  • the first electrodes 122 of the plurality of light-emitting devices 110 (including the first light-emitting device 112, the second light-emitting device 114, and the third light-emitting device 116) have a whole-layer structure.
  • the third part of the first electrode 122c is a part of the entire layer of the first electrode 122.
  • the distance d2 between the surface of the second part of the first electrode 122b away from the driving back plate 150 and the driving back plate 150 is the same as the distance d2 between the surface of the third part of the first electrode 122c away from the driving back plate 150 and the driving back plate 150 .
  • the distance d3 between them is the same or approximately the same.
  • Such an arrangement enables the thickness of the first electrodes 122 (for example, the second part of the first electrode 122b and the third part of the first electrode 122c) in different light-emitting devices 110 to be the same or approximately the same, that is, the entire layer of the first electrode 122 is
  • the thickness at different positions can be the same or approximately the same, which improves the consistency of the number of holes transmitted by the first electrode 122 to the quantum dot light-emitting layer 126 in different light-emitting devices 110, thereby improving the reliability of multiple light-emitting devices 110.
  • the filling layer 128 is also located on a side surface of the third portion of the first electrode 122 c away from the driving back plate 150 .
  • the surface of the filling layer 128 on the side away from the driving back plate 150 is flush or nearly flush with the surface on the side of the first part of the first electrode 122 a away from the driving back plate 150 , thereby improving the structural regularity of the light emitting device 110 .
  • Figure 11 is a structural diagram of a second light emitting device and a third light emitting device according to some embodiments.
  • At least two electron transport layers 130 of at least one light-emitting device 110 include a third electron transport layer 133 , a fourth electron transport layer 133 , and a fourth electron transport layer 133 . layer 134 and fifth electron transport layer 135.
  • the second light emitting device 114 and the third light emitting device 116 each include third electron transport layer 133 , fourth electron transport layer 134 and fifth electron transport layer 135 .
  • the electron mobility of the fourth electron transport layer 134 is less than the electron mobility of the third electron transport layer 133 . And the electron mobility of the fourth electron transport layer 134 is smaller than the electron mobility of the fifth electron transport layer 135 .
  • Such an arrangement can reduce the overall electron mobility of at least two layers of electron transport layers 130, reduce the number of electrons in the quantum dot light-emitting layer 126, improve the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, and improve the light-emitting device.
  • Luminous efficiency of 110 can reduce the overall electron mobility of at least two layers of electron transport layers 130, reduce the number of electrons in the quantum dot light-emitting layer 126, improve the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, and improve the light-emitting device.
  • the electron mobility of the third electron transport layer 133 is the same or approximately the same as the electron mobility of the fifth electron transport layer 135 .
  • Figure 12A is an energy level relationship diagram of the third electron transport layer, the fourth electron transport layer and the fifth electron transport layer according to some embodiments.
  • FIG. 12B is an energy level relationship diagram of the third electron transport layer, the fourth electron transport layer, and the fifth electron transport layer according to other embodiments.
  • the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 are sequentially away from the second electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 along the direction from the second electrode 124 to the quantum dot light emitting layer 126 .
  • the conduction band bottom energy level CBM3 of the third electron transport layer 133 is smaller than the conduction band bottom energy level CBM4 of the fourth electron transport layer 134 .
  • the conduction band bottom energy level CBM4 of the fourth electron transport layer 134 is smaller than the conduction band bottom energy level CBM5 of the fifth electron transport layer 135 .
  • the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135 are sequentially away from the second electrode 124 along the direction from the second electrode 124 to the quantum dot light-emitting layer 126, as shown in FIG. 12A.
  • Setting the conduction band bottom energy level CBM3 of the third electron transport layer 133 to be smaller than the conduction band bottom energy level CBM4 of the fourth electron transport layer 134 can form electron transport between the third electron transport layer 133 and the fourth electron transport layer 134 Barrier.
  • setting the conduction band bottom energy level CBM4 of the fourth electron transport layer 134 to be smaller than the conduction band bottom energy level CBM5 of the fifth electron transport layer 135 can make the connection between the fourth electron transport layer 134 and the fifth electron transport layer 134
  • An electron transport barrier is formed between the transport layers 135 .
  • the valence band top energy level VBM4 of the fourth electron transport layer 134 is smaller than the valence band top energy level VBM3 of the third electron transport layer 133 . Furthermore, the valence band top energy level VBM4 of the fourth electron transport layer 134 is smaller than the valence band top energy level VBM5 of the fifth electron transport layer 135 .
  • the valence band top energy level VBM4 of the fourth electron transport layer 134 is greater than the valence band top energy level VBM3 of the third electron transport layer 133 . Furthermore, the valence band top energy level VBM4 of the fourth electron transport layer 134 is greater than the valence band top energy level VBM5 of the fifth electron transport layer 135 .
  • the conduction band bottom energy level CBM3 of the third electron transport layer 133 is equal to the conduction band bottom energy level CBM5 of the fifth electron transport layer 135 .
  • the third electron transport layer 133 and the fifth electron transport layer 135 may be made of the same material, so that the conduction band bottom energy level CBM3 of the third electron transport layer 133 is the same as the conduction band bottom energy level CBM3 of the fifth electron transport layer 135 .
  • the energy levels CBM5 can be equal to improve the processing convenience of the light-emitting device 110 (such as the second light-emitting device 114 and the third light-emitting device 116).
  • the valence band top energy level VBM3 of the third electron transport layer 133 is equal to the valence band top energy level VBM5 of the fifth electron transport layer 135 .
  • Figure 12C is an energy level relationship diagram of the sixth electron transport layer, the seventh electron transport layer, the eighth electron transport layer and the ninth electron transport layer according to some embodiments.
  • Figure 12D is an energy level relationship diagram of the sixth electron transport layer, the seventh electron transport layer, the eighth electron transport layer, the ninth electron transport layer and the tenth electron transport layer according to some embodiments.
  • any one of the plurality of light emitting devices 110 includes a sixth electron transport layer 136.
  • the sixth electron transport layer 136 , the seventh electron transport layer 137 , the eighth electron transport layer 138 and the ninth electron transport layer 139 are sequentially away from the second electron transport layer 136 along the direction from the second electrode 124 to the quantum dot light-emitting layer 126 . Electrode 124.
  • the conduction band bottom energy level CBM12 of the sixth electron transport layer 136 is greater than the conduction band bottom energy level CBM13 of the seventh electron transport layer 137 .
  • the conduction band bottom energy level CBM13 of the seventh electron transport layer 137 is smaller than the conduction band bottom energy level CBM14 of the eighth electron transport layer 138 .
  • the conduction band bottom energy level CBM14 of the eighth electron transport layer 138 is greater than the conduction band bottom energy level CBM15 of the ninth electron transport layer 139 .
  • Such an arrangement enables an electron transmission barrier to be formed between the sixth electron transport layer 136, the seventh electron transport layer 137, the eighth electron transport layer 138 and the ninth electron transport layer 139 to hinder the transmission of electrons to the quantum dot light-emitting layer 126.
  • the number of electrons in the quantum dot light-emitting layer 126 is reduced, and the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126 is improved, thereby improving the luminous efficiency of the light-emitting device 110 .
  • the valence band top energy level VBM12 of the sixth electron transport layer 136 is smaller than the valence band top energy level VBM13 of the seventh electron transport layer 137 .
  • the valence band top energy level VBM13 of the seventh electron transport layer 137 is greater than the valence band top energy level VBM14 of the eighth electron transport layer 138 .
  • the valence band top energy level VBM14 of the eighth electron transport layer 138 is smaller than the valence band top energy level VBM15 of the ninth electron transport layer 139 .
  • any one of the plurality of light emitting devices 110 includes a sixth electron transport layer 136.
  • the sixth electron transport layer 136 , the seventh electron transport layer 137 , the eighth electron transport layer 138 , the ninth electron transport layer 139 and the tenth electron transport layer 141 are formed along the second electrode 124 to the quantum dot light-emitting layer 126 direction, away from the second electrode 124 in turn.
  • the conduction band bottom energy level CBM12 of the sixth electron transport layer 136 is greater than the conduction band bottom energy level CBM13 of the seventh electron transport layer 137 .
  • the conduction band bottom energy level CBM13 of the seventh electron transport layer 137 is smaller than the conduction band bottom energy level CBM14 of the eighth electron transport layer 138 .
  • the conduction band bottom energy level CBM14 of the eighth electron transport layer 138 is greater than the conduction band bottom energy level CBM15 of the ninth electron transport layer 139 .
  • the conduction band bottom energy level CBM15 of the ninth electron transport layer 139 is smaller than the conduction band bottom energy level CBM16 of the tenth electron transport layer 141 .
  • Such an arrangement enables an electron transmission barrier to be formed between the sixth electron transport layer 136, the seventh electron transport layer 137, the eighth electron transport layer 138, the ninth electron transport layer 139 and the tenth electron transport layer 141 to prevent electrons from traveling to
  • the transmission of the quantum dot light-emitting layer 126 reduces the number of electrons in the quantum dot light-emitting layer 126 and improves the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, thereby improving the luminous efficiency of the light-emitting device 110.
  • the valence band top energy level VBM12 of the sixth electron transport layer 136 is smaller than the valence band top energy level VBM13 of the seventh electron transport layer 137 .
  • the valence band top energy level VBM13 of the seventh electron transport layer 137 is greater than the valence band top energy level VBM14 of the eighth electron transport layer 138 .
  • the valence band top energy level VBM14 of the eighth electron transport layer 138 is smaller than the valence band top energy level VBM15 of the ninth electron transport layer 139 .
  • the valence band top energy level VBM15 of the ninth electron transport layer 139 is greater than the valence band top energy level VBM16 of the tenth electron transport layer 146 .
  • a magnetron sputtering process may be used to form at least two electron transport layers 130 .
  • the preparation methods of the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135 are illustrated below.
  • the power of the first radio frequency source may be Set to 20W ⁇ 150W.
  • the power of the first RF source can be 50W ⁇ 100W.
  • the power of the second RF source can be set to 20W ⁇ 150W.
  • the power of the second RF source can be 50W ⁇ 100W.
  • the target shutter of the first RF source is opened to deposit the third electron transport layer 133 on the ITO substrate.
  • the first RF source can be used to sputter ZnO
  • the third electron transport layer 133 is a ZnO film.
  • the target baffle of the second RF source is opened, and the first RF source and the second RF source are co-sputtering, so that the fourth electron transport layer 134 is deposited on the third electron transport layer 133 away from the ITO.
  • One side of the substrate that is, the second electrode 124).
  • the second radio frequency source can be used to sputter MgO, and the first radio frequency source and the second radio frequency source are co-sputtering, so that Mg ions and Zn ions can be deposited on the ITO substrate to form an MgZnO film.
  • the content ratio of different elements in the fourth electron transport layer 134 can be controlled to meet different usage requirements.
  • the second RF source is turned off, and the first RF source continues sputtering to form the fifth electron transport layer 135 on the side of the fourth electron transport layer 134 away from the third electron transport layer 133 .
  • the fifth electron transport layer 135 is a ZnO thin film.
  • stop sputtering After 5 to 15 minutes, stop sputtering.
  • the ITO substrate after depositing at least two electron transport layers 130 is taken out of the process chamber.
  • the first radio frequency source when forming the stacked three electron transport layers 130 (including the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 ), may be The power is set to 20W ⁇ 150W.
  • the power of the first RF source can be 50W ⁇ 100W.
  • the power of the second RF source can be set to 20W ⁇ 150W.
  • the power of the second RF source can be 50W ⁇ 100W.
  • the target shutter of the first RF source is opened to deposit the third electron transport layer 133 on the ITO substrate.
  • the first RF source can be used to sputter ZnO
  • the third electron transport layer 133 is a ZnO film.
  • the fourth electron transport layer 134 is deposited on the third electron transport layer 133 away from the ITO substrate (that is, the second electrode 124) side.
  • the second radio frequency source can be used to sputter MgZnO
  • the fourth electron transport layer 134 is an MgZnO film.
  • the fifth electron transport layer 135 is a ZnO thin film. After 5 to 15 minutes, stop sputtering.
  • the ITO substrate after depositing at least two electron transport layers 130 is taken out of the process chamber.
  • four, five, six or at least two layers of electron transport layers 130 arranged in a stack may also be formed.
  • Figure 13 is an energy level structure diagram of a light-emitting device according to other embodiments.
  • the direction of arrow g is the direction in which energy levels (including the top energy level VBM of the valence band and the bottom energy level CBM of the conduction band) increase.
  • Arrow e - represents the migration path of electrons
  • arrow h + represents the migration path of holes.
  • the material of the second electrode 124 of the second light-emitting device 114 is ITO, and the conduction band bottom energy level CBM6 is -4.7 eV.
  • the third electron transport layer 133 is a ZnO film, the conduction band bottom energy level CBM3 is -4.1eV, and the valence band top energy level VBM3 is -7.3eV.
  • the fourth electron transport layer 134 is a ZnMgO film, the conduction band bottom energy level CBM4 is -3.9eV, and the valence band top energy level VBM4 is -7.4eV.
  • the fifth electron transport layer 135 is a ZnO film, the conduction band bottom energy level CBM5 is -4.1eV, and the valence band top energy level VBM5 is -7.3eV.
  • the material of the green quantum dot light-emitting layer (English full name: Green Quantum Dot, English abbreviation: GQD) is a CdSe series quantum dot material.
  • the conduction band bottom energy level CBM17 is -3.9eV
  • the valence band top energy level VBM17 is -6.3eV.
  • the first hole transport layer 1461 is a TCTA film, the conduction band bottom energy level CBM8 is -2.3eV, and the valence band top energy level VBM8 is -5.7eV.
  • the second hole transport layer 1462 is an NPB film, the conduction band bottom energy level CBM9 is -2.4eV, and the valence band top energy level VBM9 is -5.4eV.
  • the hole injection layer 144 is a MoO 3 film, the conduction band bottom energy level CBM10 is -6.0eV, and the valence band top energy level VBM10 is -9.0eV.
  • the materials of the first electrode 122 are Mg and Ag (the mass ratio of Mg and Ag is 2:8), and the conduction band bottom energy level CBM11 is -4.1eV.
  • the material of the third electron transport layer 133 includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO.
  • the material of the fourth electron transport layer 134 is any one of ZnO, GZO, AZO, IZO, IGZO and ZnMgO.
  • the material of the five electron transport layers 135 includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO. And the material of the fourth electron transport layer 134 is different from the material of the third electron transport layer 133 . And/or, the material of the fourth electron transport layer 134 is different from the material of the fifth electron transport layer 135 .
  • This arrangement enables the electron mobility of the fourth electron transport layer 134 to be smaller than the electron mobility of the third electron transport layer 133 , and also enables the electron mobility of the fourth electron transport layer 134 to be smaller than the electron mobility of the fifth electron transport layer 135 migration rate.
  • an electron transmission barrier can be formed between the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 , hindering the transmission of electrons to the quantum dot light-emitting layer 126 , and increasing the number of electrons in the quantum dot light-emitting layer 126 .
  • the number of holes is consistent with the number of holes, thereby improving the luminous efficiency of the light-emitting device 110 .
  • the third electron transport layer 133 when the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 are sequentially away from the second electrode 124 along the direction from the second electrode 124 to the quantum dot light emitting layer 126 , the third The material of the electron transport layer 133 includes ZnO, the material of the fourth electron transport layer 134 includes ZnMgO, and the material of the fifth electron transport layer 135 includes ZnO.
  • the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135 can also be other n-type oxide films.
  • each of the at least two electron transport layers 130 will affect the number of electrons in the quantum dot light-emitting layer 126 .
  • the thickness h23 of the third electron transport layer 133 Greater than 0nm and less than or equal to 40nm.
  • the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 30 nm.
  • the thickness h25 of the fifth electron transport layer 135 is greater than 0 nm and less than or equal to 40 nm.
  • the thickness h23 of the third electron transport layer 133, the thickness h24 of the fourth electron transport layer 134 and the thickness h25 of the fifth electron transport layer 135 may be the same or different.
  • the thickness h23 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 35 nm. In other examples, the thickness h23 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 30 nm. In some further examples, the thickness h23 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 25 nm.
  • the thickness h23 of the third electron transport layer 133 may be 15 nm, 20 nm, 25 nm or 35 nm, etc.
  • the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 25 nm. In other examples, the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 20 nm. In some further examples, the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 15 nm.
  • the thickness h24 of the fourth electron transport layer 134 may be 15 nm, 20 nm, 25 nm or 28 nm, etc.
  • the thickness h25 of the fifth electron transport layer 135 is greater than 0 nm and less than or equal to 35 nm. In other examples, the thickness h25 of the fifth electron transport layer 135 is greater than 0 nm and less than or equal to 30 nm. In some further examples, the thickness h25 of the fifth electron transport layer 135 is greater than 0 nm and less than or equal to 25 nm.
  • the thickness h25 of the fifth electron transport layer 135 may be 15 nm, 20 nm, 25 nm or 35 nm, etc.
  • the thickness h23 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 40 nm
  • the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 30 nm
  • the thickness h24 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 30 nm.
  • the thickness h25 of the electron transport layer 135 is greater than 0 nm and less than or equal to 40 nm, which prevents the third electron transport layer 133, the fourth electron transport layer 134 or the fifth electron transport layer 135 from being too thick (for example, the third electron transport layer 133
  • the thickness h23 of the fourth electron transport layer 134 is greater than 40 nm
  • the thickness h24 of the fourth electron transport layer 134 is greater than 30 nm
  • the thickness h25 of the fifth electron transport layer 135 is greater than 40 nm
  • the thickness of the third electron transport layer 133, the fourth electron transport layer 134 or the fifth electron transport layer 135 can also increase the light intensity of the front of the second light-emitting device 114 (away from the driving backplane 150), so that the light emitted from the front of the second light-emitting device 114 can be approximately bright.
  • Boer distribution reduces the side light intensity of the second light-emitting device 114, increases the light extraction rate of the second light-emitting device 114, increases the brightness of the second light-emitting device 114, and reduces the power consumption of the display panel 100.
  • the thickness of the third electron transport layer 133 is greater than 0 nm and less than or equal to 30nm.
  • the thickness of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 20 nm.
  • the thickness of the fifth electron transport layer 135 is greater than 0 nm and less than or equal to 30 nm.
  • the thickness h33 of the third electron transport layer 133, the thickness h34 of the fourth electron transport layer 134 and the thickness h35 of the fifth electron transport layer 135 may be the same or different.
  • the thickness h33 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 25 nm. In other examples, the thickness h33 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 20 nm. In some further examples, the thickness h33 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 15 nm.
  • the thickness h33 of the third electron transport layer 133 may be 15 nm, 20 nm, 25 nm or 28 nm, etc.
  • the thickness h34 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 15 nm. In other examples, the thickness h34 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 10 nm. In some further examples, the thickness h34 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 5 nm.
  • the thickness h34 of the fourth electron transport layer 134 may be 10 nm, 12 nm, 15 nm or 18 nm, etc.
  • the thickness h35 of the third electron transport layer 135 is greater than 0 nm and less than or equal to 25 nm. In other examples, the thickness h35 of the third electron transport layer 135 is greater than 0 nm and less than or equal to 20 nm. In some further examples, the thickness h35 of the third electron transport layer 135 is greater than 0 nm and less than or equal to 15 nm.
  • the thickness h35 of the third electron transport layer 135 may be 15 nm, 20 nm, 25 nm or 28 nm, etc.
  • the thickness h33 of the third electron transport layer 133 is greater than 0 nm and less than or equal to 30 nm
  • the thickness h34 of the fourth electron transport layer 134 is greater than 0 nm and less than or equal to 20 nm.
  • the thickness h35 of the electron transport layer 135 is greater than 0 nm and less than or equal to 30 nm, which prevents the third electron transport layer 133, the fourth electron transport layer 134 or the fifth electron transport layer 135 from being too thick (for example, the third electron transport layer 133
  • the thickness h33 of the fourth electron transport layer 134 is greater than 30 nm, the thickness h34 of the fourth electron transport layer 134 is greater than 20 nm, or the thickness h35 of the fifth electron transport layer 135 is greater than 30 nm), causing the turn-on voltage of the third light-emitting device 116 to increase, the current to decrease, and the brightness to decrease. Affects the performance of the third light emitting device 116.
  • the thickness of the third electron transport layer 133, the fourth electron transport layer 134 or the fifth electron transport layer 135 from being too large (for example, the thickness h33 of the third electron transport layer 133 is greater than 30 nm, and the thickness h34 of the fourth electron transport layer 134 is greater than 20 nm or the thickness h35 of the fifth electron transport layer 135 is greater than 30 nm), it can also increase the light intensity of the front side of the third light-emitting device 116 (away from the driving backplane 150), so that the light emitted from the front side of the third light-emitting device 116 can be approximately bright.
  • Boer distribution reduces the side light intensity of the third light-emitting device 116, increases the light extraction rate of the third light-emitting device 116, increases the brightness of the third light-emitting device 116, and reduces the power consumption of the display panel 100.
  • the second light-emitting device 114 includes the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135, the value range of the thickness h23 of the third electron transport layer 133 is 5 nm. ⁇ 20 nm, the thickness h24 of the fourth electron transport layer 134 ranges from 1 nm to 15 nm, and the thickness h25 of the fifth electron transport layer 135 ranges from 5 nm ⁇ 20 nm.
  • the thickness h23 of the third electron transport layer 133 may range from 8 nm to 18 nm or from 5 nm to 15 nm.
  • the thickness h23 of the third electron transport layer 133 may range from 6 nm, 10 nm, 15 nm or 18 nm.
  • the thickness h24 of the fourth electron transport layer 134 may range from 1 nm to 12 nm or from 1 nm to 10 nm.
  • the thickness h23 of the third electron transport layer 133 may range from 3 nm, 8 nm, or 12 nm.
  • the thickness h25 of the fifth electron transport layer 135 may range from 8 nm to 18 nm or from 5 nm to 15 nm.
  • the thickness h25 of the fifth electron transport layer 135 may range from 6 nm, 10 nm, 15 nm or 18 nm.
  • the thickness h23 of the third electron transport layer 133 is set to a value range of 5 nm to 20 nm
  • the thickness h24 of the fourth electron transport layer 134 is set to a value range of 1 nm to 15 nm.
  • the thickness h25 of the fifth electron transport layer 135 ranges from 5 nm to 20 nm, which prevents the thickness h23 of the third electron transport layer 133, the thickness h24 of the fourth electron transport layer 134, or the thickness h25 of the fifth electron transport layer 135 from being too small.
  • the thickness h23 of the third electron transport layer 133 is less than 5 nm
  • the thickness h24 of the fourth electron transport layer 134 is less than 1 nm
  • the thickness h25 of the fifth electron transport layer 135 is less than 5 nm
  • the thickness h23 of the third electron transport layer 133, the thickness h24 of the fourth electron transport layer 134, or the thickness h25 of the fifth electron transport layer 135 is too large (for example, the thickness h23 of the third electron transport layer 133 is greater than 20 nm, The thickness h24 of the fourth electron transport layer 134 is greater than 15 nm or the thickness h25 of the fifth electron transport layer 135 is greater than 20 nm), causing the turn-on voltage of the second light-emitting device 114 to increase, the current to decrease, and the brightness to decrease, affecting the first light-emitting device 112 performance.
  • the thickness h23 of the third electron transport layer 133, the thickness h24 of the fourth electron transport layer 134, or the thickness h25 of the fifth electron transport layer 135 from being too large (for example, the thickness h23 of the third electron transport layer 133 is greater than 20 nm, The thickness h24 of the electron transport layer 134 is greater than 15 nm or the thickness h25 of the fifth electron transport layer 135 is greater than 20 nm), it can also increase the light intensity of the front side of the second light-emitting device 114 (away from the driving backplane 150) and reduce the light intensity of the second light-emitting device.
  • the side light intensity of 114 increases the light extraction rate of the first light-emitting device 112, increases the brightness of the second light-emitting device 114, and reduces the power consumption of the display panel 100.
  • the third light emitting device 116 includes the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135, the value range of the thickness h33 of the third electron transport layer 133 is 5 nm. ⁇ 15 nm, the thickness h34 of the fourth electron transport layer 134 ranges from 1 nm to 15 nm, and the thickness h35 of the fifth electron transport layer 135 ranges from 5 nm ⁇ 15 nm.
  • the thickness h33 of the third electron transport layer 133 may range from 6 nm to 13 nm or from 8 nm to 10 nm.
  • the thickness h33 of the third electron transport layer 133 may range from 6 nm, 8 nm, 9 nm or 12 nm.
  • the thickness h34 of the fourth electron transport layer 134 may range from 1 nm to 10 nm or from 1 nm to 5 nm.
  • the thickness h33 of the third electron transport layer 133 may range from 3 nm, 8 nm, 10 nm or 12 nm.
  • the thickness h35 of the fifth electron transport layer 135 may range from 6 nm to 13 nm or from 8 nm to 10 nm.
  • the thickness h35 of the fifth electron transport layer 135 may range from 6 nm, 8 nm, 9 nm or 12 nm.
  • the thickness h33 of the third electron transport layer 133 is set to a value range of 5 nm to 15 nm
  • the thickness h34 of the fourth electron transport layer 134 is set to a value range of 1 nm to 15 nm.
  • the thickness h35 of the fifth electron transport layer 135 ranges from 5 nm to 15 nm, which prevents the thickness h33 of the third electron transport layer 133, the thickness h34 of the fourth electron transport layer 134, or the thickness h35 of the fifth electron transport layer 135 from being too small.
  • the thickness h33 of the third electron transport layer 133 is less than 5 nm
  • the thickness h34 of the fourth electron transport layer 134 is less than 1 nm
  • the thickness h35 of the fifth electron transport layer 135 is less than 5 nm
  • the thickness h33 of the third electron transport layer 133, the thickness h34 of the fourth electron transport layer 134, or the thickness h35 of the fifth electron transport layer 135 is too large (for example, the thickness h33 of the third electron transport layer 133 is greater than 15 nm, The thickness h34 of the fourth electron transport layer 134 is greater than 15 nm or the thickness h35 of the fifth electron transport layer 135 is greater than 15 nm), causing the turn-on voltage of the first light-emitting device 112 to increase, the current to decrease, and the brightness to decrease, affecting the first light-emitting device 112 performance.
  • the thickness h33 of the third electron transport layer 133, the thickness h34 of the fourth electron transport layer 134, or the thickness h35 of the fifth electron transport layer 135 from being too large (for example, the thickness h33 of the third electron transport layer 133 is greater than 15 nm, the thickness h35 of the fourth electron transport layer 135 is greater than 15 nm, The thickness h34 of the electron transport layer 134 is greater than 15 nm or the thickness h35 of the fifth electron transport layer 135 is greater than 15 nm), it can also increase the light intensity of the front side of the third light-emitting device 116 (away from the driving backplane 150) and reduce the light intensity of the third light-emitting device 116 The side light intensity of 116 increases the light extraction rate of the first light-emitting device 112, increases the brightness of the third light-emitting device 116, and reduces the power consumption of the display panel 100.
  • FIG. 14A is a graph of current density as a function of voltage, according to further embodiments.
  • FIG. 14B is a graph of changes in luminous brightness with voltage according to further embodiments.
  • FIG. 14C is a graph of external quantum efficiency as a function of voltage according to further embodiments.
  • the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 in the second light emitting device 114 have different thicknesses.
  • the current density, brightness and external quantum efficiency of 114 are given as examples.
  • the third electron transport layer 133 , the fourth electron transport layer 134 and the fifth electron transport layer 135 have different thicknesses.
  • the current density, luminous brightness and external quantum efficiency of the device 114 are exemplified.
  • the abscissa represents voltage (unit V), and the ordinate represents current density (unit: milliampere/square centimeter, mA/cm 2 ).
  • the abscissa is voltage (unit V), and the ordinate is luminous brightness (unit is candela per square meter cd/m 2 ).
  • combinations 8 to 11 are combinations of electron transport layers 130 with different thicknesses and materials.
  • the third electron transport layer 133 in combination 8 is a ZnO film with a thickness of 10.5 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • the fifth electron transport layer 135 is a ZnO film with a thickness of 10.5 nm. Wherein, in the fourth electron transport layer 134, the molar percentage of Mg in ZnMgO is 8%.
  • the third electron transport layer 133 is a ZnO film with a thickness of 21 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • Combination 9 does not include the fifth electron transport layer 135 .
  • the molar percentage of Mg in ZnMgO is 8%.
  • the third electron transport layer 133 in combination 10 is a ZnMgO film with a thickness of 9 nm.
  • the fourth electron transport layer 134 is a ZnO film with a thickness of 21 nm.
  • Combination 10 also does not include the fifth electron transport layer 135 .
  • the molar percentage of Mg in ZnMgO is 8%.
  • the materials of the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135 are all ZnO. That is, at this time, at least two electron transport layers 130 can be regarded as one side of the electron transport layer. 130, with a thickness of 30nm.
  • the second light-emitting device 114 selected from combination 9, combination 10 and combination 11 increases the luminous brightness and the current density also increases, causing the current efficiency to decrease, and, as shown in As shown in FIG. 14C , when combination 9, combination 10 or combination 11 is selected, the EQE of the second light-emitting device 114 is smaller.
  • combination 8 when the voltage increases, combination 8 is selected (that is, the material of the third electron transport layer 133 is ZnO and the thickness is 10.5 nm.
  • the material of the fourth electron transport layer 134 is ZnMgO and the thickness is 9 nm.
  • the material of the fifth electron transport layer 135 is ZnO, with a thickness of 10.5 nm.
  • the second light-emitting device 114 with a molar percentage of Mg in ZnMgO (8%) has the largest external quantum efficiency EQE and the highest current efficiency, which improves the second light-emitting device 114 Luminous properties.
  • the current density, luminous brightness and EQE of the second light-emitting device 114 are better than those of a single-layer electron transport layer. 130 (combination 11) and the double-layer electron transport layer 130 (combination 9 and combination 10), the current density, luminous brightness and EQE of the second light-emitting device 114. That is to say, when the three-layer electron transport layer 130 is selected, the second light-emitting device 114 can have better light-emitting performance.
  • the material of the fourth electron transport layer 134 is ZnMgO.
  • Mg ion doping can block electrons and reduce electron mobility, thereby The number of electrons in the quantum dot light-emitting layer 126 is reduced, and the luminous efficiency of the second light-emitting device 114 is improved.
  • the third electron transport layer 133 and the fourth electron transport layer 135 can be made of ZnO.
  • An energy level difference is formed between the layer 134 and the fifth electron transport layer 135, thereby forming an electron transport barrier, hindering the transport of electrons to the quantum dot light-emitting layer 126, and balancing the transport capabilities of electrons and holes in the second light-emitting device 114.
  • the thickness h23 of the third electron transport layer 133 is approximately 10.5 nm.
  • the thickness h24 of the fourth electron transport layer 134 is approximately 9 nm, and the thickness h25 of the fifth electron transport layer 135 is approximately 10.5 nm.
  • the material of the fourth electron transport layer 134 includes ZnMgO.
  • the molar percentage of Mg is greater than 0 and less than or equal to 50%; the sum of the molar percentage of Mg and the molar percentage of Zn is 1.
  • the material of the fourth electron transport layer 134 includes Zn 1-X Mg X O, where X is the mole percentage of Mg, and 1-X is the mole percentage of Zn.
  • the mole percentage of Mg in the fourth electron transport layer 134, the electron mobility of the fourth electron transport layer 134, and the energy level of the fourth electron transport layer 134 plays a regulating role, thereby regulating the number of electrons transmitted to the quantum dot light-emitting layer 126, improving the transmission balance of electrons and holes in the first light-emitting device 112, thereby improving the first The luminous efficiency of the light-emitting device 112.
  • the mole percent of Mg can be greater than 0 and less than or equal to 40%. In other examples, the mole percent of Mg may be greater than 0 and less than or equal to 30%. In still other examples, the mole percent of Mg may be greater than 0 and less than or equal to 20%.
  • the molar percentage of Mg in the fourth electron transport layer 134 may be 10%, 20%, 30% or 40%.
  • the molar percentage of Mg in the fourth electron transport layer 134 is greater than 0 and less than or equal to 50%, the molar percentage of Zn is greater than or equal to 50% and less than 100%.
  • the molar percentage of Mg in the fourth electron transport layer 134 ranges from 1% to 20%.
  • the mole percentage of Mg in the fourth electron transport layer 134 may range from 2% to 20%, 5% to 15%, or 7% to 12%.
  • the molar percentage of Mg in the fourth electron transport layer 134 may be 5%, 8%, 10% or 15%.
  • the mole percentage of Mg in the fourth electron transport layer 134, the electron mobility of the fourth electron transport layer 134, and the energy level of the fourth electron transport layer 134 plays a regulating role, thereby regulating the number of electrons transmitted to the quantum dot light-emitting layer 126, improving the transmission balance of electrons and holes in the first light-emitting device 112, thereby improving the first The luminous efficiency of the light-emitting device 112.
  • FIG. 15A is a graph of current density as a function of voltage, according to further embodiments.
  • FIG. 15B is a graph of changes in luminous brightness with voltage according to further embodiments.
  • FIG. 15C is a graph of external quantum efficiency as a function of voltage according to further embodiments.
  • the abscissa represents voltage (unit V), and the ordinate represents current density (unit: milliampere/square centimeter, mA/cm 2 ).
  • the abscissa is voltage (unit V), and the ordinate is luminous brightness (unit is candelas per square meter cd/m 2 ).
  • combinations 12 to 16 are combinations of different electron transport layers 130 when the molar percentage of Mg in the fourth electron transport layer 132 is different.
  • the third electron transport layer 133 is a ZnO film with a thickness of 10.5 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • the fifth electron transport layer 135 is a ZnO film with a thickness of 10.5 nm. Wherein, in the fourth electron transport layer 134, the molar percentage of Mg in ZnMgO is 8%.
  • the third electron transport layer 133 is a ZnO film with a thickness of 10.5 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • the fifth electron transport layer 135 is a ZnO film with a thickness of 10.5 nm. Among them, in the fourth electron transport layer 134, the molar percentage of Mg in ZnMgO is 6.5%.
  • the third electron transport layer 133 is a ZnO film with a thickness of 10.5 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • the fifth electron transport layer 135 is a ZnO film with a thickness of 10.5 nm. Wherein, in the fourth electron transport layer 134, the molar percentage of Mg in ZnMgO is 5%.
  • the third electron transport layer 133 is a ZnO film with a thickness of 10.5 nm.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm.
  • the fifth electron transport layer 135 is a ZnO film with a thickness of 10.5 nm.
  • the molar percentage of Mg in ZnMgO is 2.5%.
  • the materials of the third electron transport layer 133, the fourth electron transport layer 134 and the fifth electron transport layer 135 are all ZnO. That is, at this time, at least two electron transport layers 130 can be regarded as one side of the electron transport layer. 130, with a thickness of 30nm.
  • the second light-emitting device 114 uses a three-layer electron transport layer 130 (including a third electron transport layer 133 , a fourth electron transport layer 134 and a fifth electron transport layer 135 , for example (combination 12, When combination 13, combination 14 and combination 15), the current density, luminous brightness and EQE are better than the single-layer electron transport layer 130 (combination 16), that is, when the three-layer electron transport layer 130 is used, the second The light-emitting device 114 can have better light-emitting performance.
  • a three-layer electron transport layer 130 including a third electron transport layer 133 , a fourth electron transport layer 134 and a fifth electron transport layer 135 , for example (combination 12, When combination 13, combination 14 and combination 15), the current density, luminous brightness and EQE are better than the single-layer electron transport layer 130 (combination 16), that is, when the three-layer electron transport layer 130 is used, the second The light-emitting device 114 can have better light-emitting performance.
  • the material of the fourth electron transport layer 134 is ZnMgO, and the electron mobility can be reduced through Mg ion doping. , thereby reducing the number of electrons in the quantum dot light-emitting layer 126 and improving the luminous efficiency of the second light-emitting device 114.
  • the material of the third electron transport layer 133 when the material of the third electron transport layer 133 is ZnO, the material of the fourth electron transport layer 134 is ZnMgO, and the material of the fifth electron transport layer 135 is ZnO, the material of the third electron transport layer 133 can be ZnO, The material of the fourth electron transport layer 134 is ZnMgO, and the material of the fifth electron transport layer 135 is ZnO.
  • An energy level difference is formed between them, thereby forming an electron transport barrier, hindering the transmission of electrons to the quantum dot light-emitting layer 126, and balancing the second light-emitting device 114. The ability to transport electrons and holes.
  • the second light-emitting device 114 using combination 12 has the largest external quantum efficiency EQE and the highest current efficiency, which improves the luminescence performance of the second light-emitting device 114 .
  • the molar percentage of Mg in the fourth electron transport layer 134 is approximately is 8%.
  • the fourth electron transport layer 134 is a ZnMgO film with a thickness of 9 nm, wherein the molar percentage of Mg in ZnMgO is 8%.
  • the electron transport layer 135 is a ZnO thin film.
  • the values of the conduction band bottom energy level CBM and the valence band top energy level VBM of ZnO films, ZnMgO films (in which the mole percentage of Mg is 5%), and ZnMgO films (in which the mole percentage of Mg is 8%) As shown in Table 1.
  • the energy level of the electron transport layer 130 can be adjusted, so that at least two An electron barrier is formed between the electron transport layers 130 to hinder the transmission of electrons to the quantum dot light-emitting layer 126, thereby improving the consistency of electron mobility and hole mobility, thereby improving the luminous efficiency of the light-emitting device 110.
  • Figure 16 is a flowchart of steps of a method for preparing a light emitting device according to some implementations.
  • embodiments of the present disclosure provide a method of manufacturing a display panel. It can be understood that the display panel preparation method provided by the embodiment of the present disclosure is used to prepare the display panel 100 as described above, and therefore has all the above-mentioned beneficial effects, which will not be described again here.
  • a method of manufacturing a display panel includes forming a plurality of light emitting devices. Among them, as shown in Figure 16, the steps of forming a light-emitting device include:
  • Step S101 forming a second electrode.
  • Step S102 Use a magnetron sputtering process to form at least two electron transport layers on one side of the second electrode.
  • the material of at least one of the at least two electron transport layers includes an oxide.
  • magnetron sputtering is used to form at least two electron transport layers 130.
  • the surface state of the oxide (such as ZnO) in the formed electron transport layer 130 can be reduced, thereby reducing the size of the electron transport layer.
  • the interaction between the oxide in 130 and the quantum dot light-emitting layer 126 is beneficial to reducing the loss of non-radiative recombination (such as Auger recombination) caused by interface defects and improving the luminous efficiency of the light-emitting device 110.
  • the impact of the later-formed electron transport layer 130 on the previously formed electron transport layer 130 can be reduced, and the previously formed electron transport layer 130 is not easily damaged, so that at least two electron transport layers can be flexibly controlled. 130, etc., so as to flexibly control the optical and electrical properties of the first light-emitting device 112, improve the consistency of electron mobility and hole mobility in the first light-emitting device 112, and balance the electrons in the first light-emitting device 112. and hole transport capabilities, thereby improving the consistency of the number of electrons and holes in the quantum dot light-emitting layer 126, and improving the luminous efficiency of the first light-emitting device 112.
  • the ZnO film formed by the magnetron sputtering process the ZnO will not be in the form of nanoparticles or only a small amount, thereby reducing the surface roughness of the ZnO film.
  • using a magnetron sputtering process to form at least two layers of electron transport layers 130 can also match high-resolution displays, and the process is simple and can be adapted to the preparation process of the driving backplane 150 to improve the display performance of the display panel 100 , reducing the production cost of the display panel 100 .
  • the material of at least one of the at least two electron transport layers 130 includes an oxide, so that electrons can pass through the electron transport layer and migrate into the quantum dot light-emitting layer 126 .
  • the material of any electron transport layer 130 includes any one of ZnO, GZO, AZO, IZO, IGZO, and ZnMgO, and the materials of any two adjacent electron transport layers 130 are different.
  • the different electron transport layers 130 can be measured by a time of flight secondary ion mass spectrometer (English full name: Time Of Flight Secondary Ion Mass Spectrometry, English abbreviation: TOF-SIMS) , the longitudinal depth and distribution intensity of each element are used to obtain the material and thickness of each electron transport layer 130.
  • a time of flight secondary ion mass spectrometer English full name: Time Of Flight Secondary Ion Mass Spectrometry, English abbreviation: TOF-SIMS
  • TOF-SIMS Time Of Flight Secondary Ion Mass Spectrometry
  • Step S103 Form a quantum dot light-emitting layer on the side of at least two electron transport layers away from the second electrode.
  • methods such as spin coating of quantum dot solutions, doctor blade coating of quantum dot solutions, or inkjet printing of quantum dot solutions may be used to dispose the at least two layers of electron transport layers 130 away from the second electron transport layer 130 .
  • One side of electrode 124 is coated with a quantum dot solution.
  • the baking temperature range is 80°C ⁇ 150°C, and the baking time is 5 minutes ⁇ 30 minutes.
  • the temperature of the heating platform can be controlled to 120° C. and baked for 10 minutes to form the quantum dot light-emitting layer 126 on the side of at least two electron transport layers 130 away from the second electrode 124 .
  • Step S104 Form a first electrode on a side of the quantum dot light-emitting layer away from at least two electron transport layers.
  • evaporation may be used to form the first electrode 122 on a side of the quantum dot light-emitting layer 126 away from the at least two electron transport layers 130 .

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Abstract

一种显示面板（100），包括多个发光器件（110，112，114，116）；任一个发光器件（110，112，114，116）包括第一电极（122）、第二电极（124）、量子点发光层（126）和至少两层电子传输层（130，131，132，133，134，135，136，137，138，139）；量子点发光层（126）位于第一电极（122）和第二电极（124）之间；至少两层电子传输层（130，131，132，133，134，135，136，137，138，139）层叠设置，且位于第二电极（124）和量子点发光层（126）之间。其中，多个发光器件（110，112，114，116）包括第一发光器件（112）和第二发光器件（114），第一发光器件（112）用于发射第一颜色光，第二发光器件（114）用于发射第二颜色光，第一颜色光的波长大于第二颜色光的波长；第一发光器件（112）中电子传输层（130，131，132，133，134，135，136，137，138，139）的数量，小于第二发光器件（114）中电子传输层（130，131，132，133，134，135，136，137，138，139）的数量。

Description

显示面板、显示面板的制备方法和显示装置 技术领域
本公开涉及显示技术领域，尤其涉及一种显示面板、显示面板的制备方法和显示装置。
背景技术
显示面板通常包括多个发光器件，多个发光器件用于向外发射光线，使得显示面板能够实现图像显示功能。
发明内容
第一方面，提供了一种显示面板。显示面板包括多个发光器件。任一个发光器件包括第一电极、第二电极、量子点发光层以及至少两层电子传输层。量子点发光层位于第一电极和第二电极之间。至少两层电子传输层层叠设置，且位于第二电极和量子点发光层之间。其中，多个发光器件包括第一发光器件和第二发光器件，第一发光器件用于发射第一颜色光，第二发光器件用于发射第二颜色光，第一颜色光的波长大于第二颜色光的波长。第一发光器件中电子传输层的数量，小于第二发光器件中电子传输层的数量。
在一些实施例中，第一发光器件中的至少两层电子传输层的厚度之和，大于第二发光器件中的至少两层电子传输层的厚度之和。
在一些实施例中，显示面板还包括驱动背板，多个发光器件位于驱动背板的一侧。第二电极相对于第一电极靠近驱动背板。第一发光器件包括第一部分第一电极，第二发光器件包括第二部分第一电极。第一部分第一电极远离驱动背板一侧的表面与驱动背板之间的距离，大于第二部分第一电极远离驱动背板一侧的表面与驱动背板之间的距离。
在一些实施例中，第一发光器件中的至少两层电子传输层包括第一电子传输层和第二电子传输层，第二电子传输层的电子迁移率小于第一电子传输层的电子迁移率。
在一些实施例中，第一电子传输层相对于第二电子传输层靠近第二电极。且第一电子传输层的导带底能级，小于第二电子传输层的导带底能级。
在一些实施例中，第一电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。第二电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。且第一电子传输层的材料和第二电子传输层的材料不同。
在一些实施例中，第二电子传输层的材料包括ZnMgO。第二电子传输层 中，Mg的摩尔百分比大于0，且小于或等于50％。Mg的摩尔百分比与Zn的摩尔百分比之和为1。
在一些实施例中，第二电子传输层中，Mg的摩尔百分比的取值范围为1％～20％。
在一些实施例中，第二电子传输层中，Mg的摩尔百分比大约为5％。
在一些实施例中，第一电子传输层的厚度大于0nm，且小于或等于60nm；和/或，第二电子传输层的厚度大于0nm，且小于或等于60nm。第一电子传输层的厚度大于第二电子传输层的厚度。
在一些实施例中，第一电子传输层的厚度的取值范围为30nm～50nm。和/或，第二电子传输层的厚度的取值范围为1nm～30nm。
在一些实施例中，第一电子传输层的厚度大约为45nm。和/或，第二电子传输层的厚度大约为15nm。
在一些实施例中显示面板还包括第三发光器件。第三发光器件用于发射第三颜色光。第二颜色光的波长，大于第三颜色光的波长。第一发光器件中电子传输层的数量，小于第三发光器件中电子传输层的数量。
在一些实施例中，第二发光器件和第三发光器件中，至少一个发光器件的至少两层电子传输层包括第三电子传输层、第四电子传输层和第五电子传输层。第四电子传输层的电子迁移率，小于第三电子传输层的电子迁移率。且第四电子传输层的电子迁移率，小于第五电子传输层的电子迁移率。
在一些实施例中，第三电子传输层、第四电子传输层和第五电子传输层沿第二电极至量子点发光层的方向，依次远离第二电极。其中，第三电子传输层的导带底能级，小于第四电子传输层的导带底能级。或，第四电子传输层的导带底能级，小于第五电子传输层的导带底能级。
在一些实施例中，第三电子传输层的导带底能级，与第五电子传输层的导带底能级相等。
在一些实施例中，第三电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。第四电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。第五电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。且第四电子传输层的材料与第三电子传输层的材料不同。和/或，第四电子传输层的材料与第五电子传输层的材料不同。
在一些实施例中，第四电子传输层的材料包括ZnMgO，且第四电子传输层中，Mg的摩尔百分比大于0，且小于或等于50％。Mg的摩尔百分比与Zn 的摩尔百分比之和为1。
在一些实施例中，第四电子传输层中，Mg的摩尔百分比的取值范围为1％～20％。
在一些实施例中，当第二发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第四电子传输层中，Mg的摩尔百分比大约为8％。
在一些实施例中，当第二发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第三电子传输层的厚度大于0nm，且小于或等于40nm。第四电子传输层的厚度大于0nm，且小于或等于30nm。第五电子传输层的厚度大于0nm，且小于或等于40nm。当第三发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第三电子传输层的厚度大于0nm，且小于或等于30nm。第四电子传输层的厚度大于0nm，且小于或等于20nm。第五电子传输层的厚度大于0nm，且小于或等于30nm。
在一些实施例中，当第二发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第三电子传输层的厚度的取值范围为5nm～20nm，第四电子传输层的厚度的取值范围为1nm～15nm，第五电子传输层的厚度的取值范围为5nm～20nm。当第三发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第三电子传输层的厚度的取值范围为5nm～15nm，第四电子传输层的厚度的取值范围为1nm～15nm，第五电子传输层的厚度的取值范围为5nm～15nm。
在一些实施例中，当第二发光器件包括第三电子传输层、第四电子传输层和第五电子传输层时，第三电子传输层的厚度为大约10.5nm，第四电子传输层的厚度大约为9nm，第五电子传输层的厚度为大约10.5nm。
在一些实施例中，第一颜色光为红光，第二颜色光为绿光，第三颜色光为蓝光。
在一些实施例中，至少两层电子传输层的厚度之和的取值范围为5nm～150nm。
在一些实施例中，至少两层电子传输层的厚度之和的取值范围为20nm～70nm。
在一些实施例中，至少两层电子传输层的厚度之和的取值范围为20nm～60nm。
在一些实施例中，显示面板还包括电子注入层、空穴注入层、空穴传输层和光耦合层。电子注入层位于第二电极和至少两层电子传输层之间。空穴注入层位于第一电极和量子点发光层之间。空穴传输层位于空穴注入层和量 子点发光层之间。光耦合层位于第一电极远离空穴注入层的一侧。
另一方面，提供了一种显示面板的制备方法。显示面板的制备方法包括形成多个发光器件。其中，形成一个发光器件的步骤包括形成第二电极。采用磁控溅射工艺，在第二电极的一侧形成至少两层电子传输层。至少两层电子传输层中至少一层电子传输层的材料包括氧化物。在至少两层电子传输层远离第二电极的一侧形成量子点发光层。在量子点发光层远离至少两层电子传输层的一侧形成第一电极。
又一方面，提供了一种显示装置。显示装置包括如上述的显示面板。
附图说明
为了更清楚地说明本公开中的技术方案，下面将对本公开一些实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本公开的一些实施例的附图，对于本领域普通技术人员来讲，还可以根据这些附图获得其他的附图。此外，以下描述中的附图可以视作示意图，并非对本公开实施例所涉及的产品的实际尺寸、方法的实际流程、信号的实际时序等的限制。
图1为根据一些实施例的显示装置的结构图；
图2A为根据一些实施例的显示面板的结构图；
图2B为根据另一些实施例的显示面板的结构图；
图3A为根据又一些实施例的显示面板的结构图；
图3B为根据又一些实施例的显示面板的结构图；
图3C为根据又一些实施例的显示面板的结构图；
图3D为根据又一些实施例的显示面板的结构图；
图4为根据一些实施例的发光器件的亮度随电子传输层的厚度变化的曲线图；
图5A为根据又一些实施例的显示面板的结构图；
图5B为根据又一些实施例的显示面板的结构图；
图6为根据一些实施例的第一发光器件的结构图；
图7A为根据一些实施例的第一电子传输层和第二电子传输层的能级关系图；
图7B为根据另一些实施例的第一电子传输层和第二电子传输层的能级关系图；
图7C为根据又一些实施例的第一电子传输层和第二电子传输层的能级关系图；
图7D为根据又一些实施例的第一电子传输层和第二电子传输层的能级关系图；
图8为根据一些实施例的发光器件的能级结构图；
图9A为根据一些实施例的电流密度随电压的变化曲线图；
图9B为根据一些实施例的发光亮度随电压的变化曲线图；
图9C为根据一些实施例的外量子效率随电压的变化曲线图；
图10A为根据另一些实施例的电流密度随电压的变化曲线图；
图10B为根据另一些实施例的发光亮度随电压的变化曲线图；
图10C为根据另一些实施例的外量子效率随电压的变化曲线图；
图11为根据一些实施例的第二发光器件和第三发光器件的结构图；
图12A为根据一些实施例的第三电子传输层、第四电子传输层和第五电子传输层的能级关系图；
图12B为根据另一些实施例的第三电子传输层、第四电子传输层和第五电子传输层的能级关系图；
图12C为根据一些实施例的第六电子传输层、第七电子传输层、第八电子传输层和第九电子传输层的能级关系图；
图12D为根据一些实施例的第六电子传输层、第七电子传输层、第八电子传输层、第九电子传输层和第十电子传输层的能级关系图；
图13为根据另一些实施例的发光器件的能级结构图；
图14A为根据又一些实施例的电流密度随电压的变化曲线图；
图14B为根据又一些实施例的发光亮度随电压的变化曲线图；
图14C为根据又一些实施例的外量子效率随电压的变化曲线图；
图15A为根据又一些实施例的电流密度随电压的变化曲线图；
图15B为根据又一些实施例的发光亮度随电压的变化曲线图；
图15C为根据又一些实施例的外量子效率随电压的变化曲线图；
图16为根据一些实施了的发光器件的制备方法步骤流程图。
具体实施方式
下面将结合附图，对本公开一些实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本公开一部分实施例，而不是全部的实施例。基于本公开所提供的实施例，本领域普通技术人员所获得的所有其他实施例，都属于本公开保护的范围。
除非上下文另有要求，否则，在整个说明书和权利要求书中，术语“包括(comprise)”及其其他形式例如第三人称单数形式“包括(comprises)” 和现在分词形式“包括(comprising)”被解释为开放、包含的意思，即为“包含，但不限于”。在说明书的描述中，术语“一个实施例(one embodiment)”、“一些实施例(some embodiments)”、“示例性实施例(exemplary embodiments)”、“示例(example)”、“特定示例(specific example)”或“一些示例(some examples)”等旨在表明与该实施例或示例相关的特定特征、结构、材料或特性包括在本公开的至少一个实施例或示例中。上述术语的示意性表示不一定是指同一实施例或示例。此外，所述的特定特征、结构、材料或特点可以以任何适当方式包括在任何一个或多个实施例或示例中。
以下，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本公开实施例的描述中，除非另有说明，“多个”的含义是两个或两个以上。
“A、B和C中的至少一个”与“A、B或C中的至少一个”具有相同含义，均包括以下A、B和C的组合：仅A，仅B，仅C，A和B的组合，A和C的组合，B和C的组合，及A、B和C的组合。
“A和/或B”，包括以下三种组合：仅A，仅B，及A和B的组合。
如本文所使用的那样，“约”、“大致”或“近似”包括所阐述的值以及处于特定值的可接受偏差范围内的平均值，其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即，测量系统的局限性)所确定。
如本文所使用的那样，“平行”、“垂直”、“相等”包括所阐述的情况以及与所阐述的情况相近似的情况，该相近似的情况的范围处于可接受偏差范围内，其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即，测量系统的局限性)所确定。例如，“平行”包括绝对平行和近似平行，其中近似平行的可接受偏差范围例如可以是5°以内偏差；“垂直”包括绝对垂直和近似垂直，其中近似垂直的可接受偏差范围例如也可以是5°以内偏差。“相等”包括绝对相等和近似相等，其中近似相等的可接受偏差范围内例如可以是相等的两者之间的差值小于或等于其中任一者的5％。
应当理解的是，当层或元件被称为在另一层或基板上时，可以是该层或元件直接在另一层或基板上，或者也可以是该层或元件与另一层或基板之间存在中间层。
本文参照作为理想化示例性附图的剖视图和/或平面图描述了示例性实施 方式。在附图中，为了清楚，放大了层和区域的厚度。因此，可设想到由于例如制造技术和/或公差引起的相对于附图的形状的变动。因此，示例性实施方式不应解释为局限于本文示出的区域的形状，而是包括因例如制造而引起的形状偏差。例如，示为矩形的蚀刻区域通常将具有弯曲的特征。因此，附图中所示的区域本质上是示意性的，且它们的形状并非旨在示出设备的区域的实际形状，并且并非旨在限制示例性实施方式的范围。
图1为根据一些实施例的显示装置的结构图。
如图1所示，本公开的一些实施例提供了一种显示装置200。在一些示例中，显示装置200可以为笔记本电脑、移动电话、无线装置、个人数据助理(PDA)、手持式或便携式计算机、GPS接收器/导航器、相机、MP4视频播放器、摄像机、游戏控制台、手表、时钟、计算器、电视监视器、平板显示器、计算机监视器、汽车显示器(例如，里程表显示器等)、导航仪、座舱控制器和/或显示器、相机视图的显示器(例如，车辆中后视相机的显示器)、电子相片、电子广告牌或指示牌、投影仪、包装和美学结构(例如，对于一件珠宝的图像的显示器)等。
如图1所示，显示装置200包括显示面板100。可以理解地，显示面板100用于显示图像信息。示例的，显示面板100可以用于显示静态图像，例如图片或者照片。显示面板100也可以用于显示动态图像，例如视频或者游戏画面。
本公开的实施例对显示装置200不做进一步限定，下面对显示面板100进行举例说明。
图2A为根据一些实施例的显示面板的结构图。
在一些示例中，如图2A所示，显示面板100包括多个子像素101，多个子像素101位于显示面板100的显示区AA，且阵列排布。
可以理解地，子像素101是显示面板100进行画面显示的最小单元。每个子像素101可显示一种单一的颜色，例如红色、绿色或蓝色。显示面板100可以包括多个红色子像素、多个绿色子像素和多个蓝色子像素。通过调节不同颜色的子像素101的亮度(灰阶)，即可得到不同强度的红光、绿光和蓝光，而不同强度的红光、绿光和蓝光中的至少两者进行叠加，又可以显示出更多颜色的光，从而实现了显示面板100的全彩化显示。
图2B为根据另一些实施例的显示面板的结构图。
如图2B所示，在一些示例中，显示面板100包括多个发光器件110。可以理解地，一个发光器件110位于一个子像素101内，使得显示面板100能 够实现图像显示功能。
在一些示例中，多个发光器件110用于发不同颜色的光。示例的，多个发光器件110中的一部分(两个或者更多个)发光器件110用于发红光，另一部分(两个或者更多个)发光器件110用于发蓝光，又一部分(两个或者更多个)发光器件110用于发绿光，使得显示面板100能够实现全彩化显示。
在一些示例中，如图2B所示，显示面板100还包括驱动背板150。多个发光器件110位于驱动背板150的一侧。
可以理解地，多个发光器件110与驱动背板150电连接，驱动背板150用于驱动多个发光器件110独立发光，提高显示面板100的显示性能。
示例的，如图2B所示，驱动背板150包括衬底152和驱动电路层158。
在一些示例中，衬底152为硬性衬底。在另一些示例中，衬底152为柔性衬底。示例的，衬底152的材料包括塑料、FR-4等级材料、树脂、玻璃、石英、聚酰亚胺或者聚甲基丙烯酸甲酯(英文全称：Polymethyl Methacrylate，英文简称PMMA)中的任一个。
示例的，如图2B所示，驱动电路层158位于衬底152的一侧。驱动电路层158内设置有多个像素驱动电路154，一个像素驱动电路154与一个发光器件110电连接，使得驱动背板150能够实现对于多个发光器件110的单独驱动，从而使得多个发光器件110能够独立发光。
在一些示例中，像素驱动电路154包括薄膜晶体管(英文全称：Thin Film Transistor，英文简称：TFT)和电容，薄膜晶体管和电容电连接。示例的，像素驱动电路154可以为2T1C像素驱动电路(也即是包括2个TFT和1个电容)、7T1C像素驱动电路(也即是包括7和TFT和1个电容)或者3T1C像素驱动电路(也即是包括3个TFT和1个电容)等。
在一些示例中，如图2B所示，任一个发光器件110包括第一电极122、第二电极124和量子点发光层126。量子点发光层126位于第一电极122和第二电极124之间。
在一些示例中，发光器件110为量子点电致发光二极管(Quantum Dot Light-Emitting Diodes，简称QLED)。可以理解地，QLED具有发光光谱窄、色纯度高和发光效率高等优点。
在一些示例中，第一电子电极122为阳极层(英文名称：anode)，第二电极124为阴极层(英文名称：cathode)。在另一些示例中，第一电极122为阴极层，第二电极124为阳极层。本公开的实施例以第一电极122为阳极层，第二电极124为阴极层为例，继续举例说明。
示例的，如图2B所示，第二电极124位于驱动电路层158远离衬底152的一侧，且与像素驱动电路154电连接。在一些示例中，第二电极124可以与像素驱动电路154中的驱动晶体管电连接。
在一些示例中，如图2B所示，显示面板100还包括像素界定层156。像素界定层156位于第二电极124远离驱动电路层158的一侧。像素界定层156具有多个开口。量子点发光层126包括多个有效发光部1262，一个有效发光部1262位于一个开口内。
示例的，如图2B所示，第一电极122位于量子点发光层126远离第二电极124的一侧。
可以理解地，第一电极122用于提供空穴，第二电极124用于提供电子。第一电极122提供的空穴和第二电极124提供的电子能够向量子点发光层126移动，并在量子点发光层126内复合发光，使得发光器件110能够发光。
在一些示例中，可以将第二电极124相对于第一电极122靠近驱动背板150的结构称为倒置结构，将第二电极124相对于第一电极122远离驱动背板150的结构称为正置结构。本公开的实施例以倒置结构(也即是第二电极124相对于第一电极122靠近驱动背板150)为例，进行举例说明。
由上述可知，量子点发光层126用于发出光线。在一些示例中，第一电极122为透明材质，使得量子点发光层126发出的光线能够穿过第一电极122向外发射。此时，发光器件110为顶发射结构。
在另一些示例中，第二电极124为透明材质，使得量子点发光层126发出的光线能够穿过第二电极124向外发射。此时，发光器件110为底发射结构。
在又一些示例中，第一电极122和第二电极124均为透明材质，使得量子点发光层126发出的光线能够穿过第一电极122和第二电极124向外发射。此时，发光器件110为双面发射结构。本公开的实施例以发光器件110为顶发射结构为例，进行举例说明。
在一些示例中，如图2B所示，显示面板100还包括封装层160。封装层160位于发光器件110远离驱动背板150的一侧，起到保护发光器件110的作用。
在一些示例中，如图2B所示，封装层160包括第一封装层162、第二封装层164和第三封装层166。第一封装层162、第二封装层164和第三封装层166层叠设置，且依次远离发光器件110的第一电极122。
在一些示例中，第一封装层162和第三封装层166为无机膜层，第二封 装层164为有机膜层。
可以理解地，封装层160能够对外界的杂质、水或者氧气等起到阻挡作用，延长发光器件110的使用寿命。
图3A为根据又一些实施例的显示面板的结构图。图3B为根据又一些实施例的显示面板的结构图。图3C为根据又一些实施例的显示面板的结构图。
在一些示例中，如图3A所示，量子点发光层126中包括量子点(英文全称：Quantum Dot，英文简称：QD)1261。示例的，量子点1261可以为球形，也可以为四面体形、柱形或者盘形等。
在一些示例中，量子点1261可具有核壳结构，也即是，量子点1261具有一个量子点核和围绕量子点核的量子点壳。通过调节量子点核的尺寸，能够对量子点发光层126发出的光线颜色起到调节作用，从而使得发光器件110能够发出不同颜色的光。
示例的，当量子点核的尺寸增加时，量子点1261具有较窄的能带隙，因此配置成发射波长较长的光。而当量子点的尺寸减小时，量子点1261具有较宽的能带隙，因此配置成发射波长较短的光。
在一些示例中，如图3A所示，多个发光器件110包括第一发光器件112和第二发光器件114，第一发光器件112用于发射第一颜色光，第二发光器件114用于发射第二颜色光。第一颜色光的波长大于第二颜色光的波长。
在一些示例中，第一颜色光为红光(波长约为600nm～700nm)，第二颜色光为绿光(波长约为500nm～570nm)。
在一些示例中，第一发光器件112中的量子点1261的量子点核的尺寸，大于第二发光器件114中的量子点1261的量子点核的尺寸。
通过调节不同发光器件110(第一发光器件112和第二发光器件114)中，量子点1261中的量子点核的尺寸，使得第一发光器件112和第二发光器件114能够发射出不同颜色的光。
下面参照图3A～图3C，对发光器件110的结构进行举例说明。
由上述可知，如图3A～图3C所示，任一个发光器件110包括第一电极122、第二电极124和位于第一电极122和第二电极124之间的量子点发光层126。
在一些示例中，第一电极122的材料包括Mg和Ag。示例的，Mg和Ag的质量之比为2:8，使得第一电极122能够提供更多的空穴。第二电极124的材料包括ITO(英文全称：Indium Tin Oxide，中文名称：氧化铟锡)，使得第二电极124能够提供更多的电子。
在一些示例中，如图3A所示，第一电极122的厚度h3的取值范围为8nm～12nm。示例的，第一电极122的厚度h3的取值范围可以为9nm～11nm或者9.5nm～10.5nm等。示例的，第一电极122的厚度h3的取值可以为9nm、10nm或者11nm等。
在一些示例中，如图3A所示，第二电极124的厚度h4的取值范围为50nm～100nm。示例的，第二电极124的厚度h4的取值范围可以为60nm～90nm或者70nm～80nm等。示例的，第二电极124的厚度h4的取值可以为60nm、70nm、80nm或者90nm等。
可以理解地，设置第一电极122的厚度h3的取值范围为8nm～12nm，第二电极124的厚度h4的取值范围为50nm～100nm，避免了第一电极122或者第二电极124的厚度过小(例如第一电极122小于8nm，或者第二电极124小于50nm)，并且还避免了第一电极122或者第二电极124的厚度过大(例如第一电极122大于12nm，或者第二电极124大于100nm)，使得第一电极122能够为量子点发光层126提供充足的空穴，第二电极124能够为量子点发光层126提供充足的电子，提高发光器件110的发光效率。
在一些示例中，可以采用旋涂量子点溶液、刮涂量子点溶液或者喷墨打印量子点溶液等方式，在第二电极124的一侧形成量子点发光层126。
示例的，量子点溶液可以为II-VI族半导体化合物(例如CdSe硒化镉、ZnTeSe锌碲硒等)、III-V族半导体化合物(例如InP磷化铟)、IV-VI族半导体化合物(例如PbS硫化铅)中的至少一个。在一些示例中，量子点溶液还可以为钙钛矿量子点溶液。
可以理解地，采用旋涂量子点溶液的方式形成量子点发光层126时，通过控制量子点溶液的浓度或者旋涂的转速等，能够对量子点发光层126的厚度h5起到控制作用。
在一些示例中，如图3A所示，量子点发光层126的厚度h5的取值范围为10nm～80nm。示例的，量子点发光层126的厚度h5的取值范围可以为20nm～50nm或者25nm～40nm等。示例的，量子点发光层126的厚度h5可以为20nm、30nm、40nm、60nm或者75nm等。
设置量子点发光层126的厚度h5的取值范围为10nm～80nm，避免了量子点发光层126的厚度过小(例如小于10nm)或者过大(例如大于80nm)，提高发光器件110的发光效率。
在一些示例中，如图3B所示，显示面板100还包括空穴注入层(英文全称：Hole Injection Layer，英文简称：HIL)144。空穴注入层144位于第一电 极122和量子点发光层126之间。
在一些示例中，空穴注入层144的材料包括MoO 3(中文名称：三氧化钼)。
在一些示例中，在一些示例中，空穴注入层144的厚度h8的取值范围为2nm～20nm。示例的，空穴注入层144的厚度h8的取值范围可以为3nm～17nm或者5nm～10nm等。示例的，空穴注入层144的厚度h8的取值可以为5nm、8nm、10nm或者12nm等。
可以理解地，通过设置空穴注入层144，能够提高量子点发光层126中空穴的数量，从而提高发光器件110的发光效率。
并且，设置空穴注入层144的厚度h8的取值范围为2nm～20nm，避免了空穴注入层144的厚度h8过小(例如小于2nm)，或者空穴注入层144的厚度h8过大(例如大于20nm)，提高发光器件110的发光效率。
在一些示例中，如图3B所示，发光器件110还包括空穴传输层(英文全称：Hole Transport Layer，英文简称：HTL)146。空穴传输层146位于空穴注入层144和量子点发光层126之间。
可以理解地，空穴传输层146起到传输空穴的作用。故而，将空穴传输层146设置于空穴注入层144和量子点发光层126之间，能够提高第一电极122中的空穴的迁移率，也即是增大第一电极122中空穴向量子点发光层126中迁移的数量，提高发光器件110的发光效率。
在一些示例中，空穴传输层146为有机材料。
在一些示例中，如图3B所示，空穴传输层146包括第一空穴传输层1461和第二空穴传输层1462，第一空穴传输层相对于第二空穴传输层1462靠近量子点发光层126。
示例的，第一空穴传输层1461的材料包括TCTA(中文名称：4,4',4”-三(咔唑-9-基)三苯胺)，第二空穴传输层1462的材料包括NPB(中文名称：N,N’-二(萘-1-基)-N,N'-二苯基-联苯胺)。
在一些示例中，如图3B所示，第一空穴传输层1461的厚度h6的取值范围为2nm～20nm。示例的，第一空穴传输层1461的厚度h6的取值范围可以为3nm～17nm或者5nm～10nm等。示例的，第一空穴传输层1461的厚度h6的取值可以为5nm、8nm、10nm或者12nm等。
在一些示例中，如图3B所示，第二空穴传输层1462的厚度h7的取值范围为10nm～50nm。示例的，第二空穴传输层1462的厚度h7的取值范围可以为15nm～45nm或者20nm～30nm等。示例的，第二空穴传输层1462的厚度h7的取值可以为20nm、25nm、30nm、35nm或者45nm等。
可以理解地，设置空穴传输层146包括第一空穴传输层1461和第二空穴传输层1462，并且，第一空穴传输层1461的材料包括TCTA，第二空穴传输层1462的材料包括NPB，能够增大第一电极122中空穴向量子点发光层126中移动的数量，提高发光器件110的发光效率。
此外，设置第一空穴传输层1461的厚度h6的取值范围为2nm～20nm，第二空穴传输层1462的厚度h7的取值范围为10nm～50nm，避免了第一空穴传输层1461或者第二空穴传输层1462的厚度过小(例如第一空穴传输层1461小于2nm，或者第二空穴传输层1462小于10nm)，还能够避免第一空穴传输层1461或者第二空穴传输层1462的厚度过大(例如第一空穴传输层1461大于20nm，或者第二空穴传输层1462大于50nm)，提高了第一空穴传输层1461和第二空穴传输层1462对于空穴的传输效率，增大量子点发光层126中空穴的数量，从而提高发光器件110的发光效率。
在一些示例中，如图3C所示，显示面板100还包括光耦合层148。光耦合层148位于第一电极122远离空穴注入层144的一侧。
示例的，光耦合层148的折射率与第一电极122的折射率不同。在一些示例中，光耦合层148的折射率大于第一电极122的折射率。
由于光线能够穿过第一电极122向外发射，故而，设置光耦合层148的折射率大于第一电极122的折射率，使得穿过第一电极122的光线能够照射至光耦合层148内，并穿过光耦合层148射出发光器件110，避免光线在第一电极122和光耦合层148的接触面发生全反射，从而能够提高发光器件110的出光率，提高光线利用率，增大发光器件110的亮度，降低显示面板100功耗。
在一些示例中，光耦合层148的材料包括NPB(中文名称：N,N’-二(萘-1-基)-N,N'-二苯基-联苯胺)。
在一些示例中，光耦合层148的厚度h9的取值范围为40nm～80nm。示例的，光耦合层148的厚度的取值范围可以为50nm～70nm或者55nm～65nm等。示例的，光耦合层148的厚度可以为55nm、60nm、70nm或者75nm等。
可以理解地，设置光耦合层148的厚度h9的取值范围为40nm～80nm，避免了光耦合层148的厚度过小(例如小于40nm)或者过大(例如大于80nm)，提高了发光器件110的出光率，增大发光器件110的亮度，降低显示面板100的功耗。
由上述可知，第一电极122中的空穴和第二电极124中的电子传输至量子点发光层126，并在量子点发光层126中复合发光。但是，发光器件110中 电子的迁移率通常大于空穴的迁移率，导致电子和空穴的传输不平衡，造成量子点发光层126中电子的数量大于空穴的数量。
可以理解地，量子点发光层126中电子的数量大于空穴的数量，会造成电子和空穴在量子点发光层126中产生俄歇复合。也即是，电子和空穴复合后没有发光，而是将能量通过碰撞的方式，转移给另一个电子或者空穴，造成该电子或者空穴跃迁。
可以理解地，当电子和空穴产俄歇复合时，一方面，降低了发光器件110的发光效率，另一方面，俄歇复合会产生热量，导致量子点发光层126温度升高，影响量子点发光层126、以及与量子点发光层126相邻的其他膜层(例如电子传输层130和空穴传输层146)的寿命，从而影响发光器件110的使用寿命。
基于此，如图3A～图3C所示，任一个发光器件110还包括至少两层电子传输层130。至少两层电子传输层130层叠设置，且位于第二电极124和量子点发光层126之间。
可以理解地，至少两层电子传输层(英文全称：Electronic Transport Layer，英文简称：ETL)130起到传输电子的作用。故而，将至少两层电子传输层130层叠设置于第二电极124和量子点发光层126之间，使得电子能够通过至少两层电子传输层130向量子点发光层126传输。
这样一来，通过改变至少两层电子传输层130中，至少一层电子传输层130的材料或者厚度等，就能够对至少一层电子传输层130的电子迁移率或者能级起到调节作用，从而对传输至量子点发光层126中电子的数量起到调节作用，均衡发光器件110中电子的迁移率和空穴的迁移率，提高量子点发光层126中电子数量和空穴数量的一致性，减少电子和空穴在量子点发光层126中发生俄歇复合的情况，从而提高发光器件110的发光效率，延长发光器件110的使用寿命。
由上述可知，多个发光器件110包括第一发光器件112和第二发光器件114。第一发光器件112用于发射第一颜色光，第二发光器件114用于发射第二颜色光，第一颜色光的波长大于第二颜色光的波长。
在一些实施例中，如图3A～图3C所示，第一发光器件112中电子传输层130的数量，小于第二发光器件114中电子传输层130的数量。
可以理解地，通过调节电子传输层130的数量，能够对传输至量子点发光层126中的电子数量起到调节所用。
故而，设置第一发光器件112中电子传输层130的数量，小于第二发光 器件114中电子传输层130的数量，也即是，根据发光器件110的发光颜色(发光波长)，有针对性地设置不同数量的电子传输层130。
这样一来，就能够分别调节不同颜色的发光器件110中，量子点发光层126中的电子数量，有针对性地提高不同颜色的发光器件110中，量子点发光层126中电子数量和空穴数量的一致性，从而有针对性地提高不同颜色发光器件110的发光效率，延长不同颜色发光器件110的使用寿命。
在一些示例中，如图3B所示，显示面板100还包括电子注入层(英文全称：Electron Inject Layer，英文简称：EIL)142。电子注入层142位于第二电极124和至少两层电子传输层130之间。
在一些示例中，电子注入层142为ZnO(氧化锌)薄膜。
在另一些示例中，如图3C所示，发光器件110也可以不包括电子注入层142。
图3D为根据又一些实施例的显示面板的结构图。
在一些实施例中，如图3D所示，第一发光器件112中的至少两层电子传输层130的厚度之和h1，大于第二发光器件114中的至少两层电子传输层130的厚度之和h2。
可以理解地，以第一发光器件112为例，第一发光器件112中至少两层电子传输层130的厚度之和h1，为第一发光器件112中所有电子传输层130(两层、三层或者更多层)的厚度之和。
可以理解地，通过调节至少两层电子传输层130的厚度之和，能够对传输至量子点发光层126中的电子数量起到调节所用。
故而，设置第一发光器件112中的至少两层电子传输层130的厚度之和h1，大于第二发光器件114中的至少两层电子传输层130的厚度之和h2，也即是，根据发光器件110的发光颜色(发光波长)，有针对性地设置不同的至少两层电子传输层130的厚度之和。
这样一来，就能够分别调节不同颜色的发光器件110中，量子点发光层126中的电子数量，有针对性地提高不同颜色的发光器件110中，量子点发光层126中电子数量和空穴数量的一致性，从而有针对性地提高不同颜色发光器件110的发光效率，延长不同颜色发光器件110的使用寿命。
图4为根据一些实施例的发光器件的亮度随电子传输层的厚度变化的曲线图。
示例的，本公开的实施例以第二电极124的材料为ITO，厚度为70nm，量子点发光层126的厚度为30nm，第一空穴传输层1461的材料为TCTA，厚 度为10nm，第二空穴传输层1462的材料为NPB，厚度为30nm，空穴注入层144的材料为MoO 3，厚度为7nm，第一电极122材料为Mg和Ag(Mg和Ag的质量之比为2:8)，厚度为10nm，至少两层电子传输层130均为ZnO(氧化锌)薄膜为例，对发光器件110的发光亮度(也即是发光器件110远离驱动背板150一侧的出光强度)随至少两层电子传输层130的厚度之和的变化进行了仿真。
需要说明的是，图4中，横坐标为至少两层电子传输层130的厚度之和，单位为nm，纵坐标为发光器件110的发光亮度，单位为坎德拉每平方米(cd/m 2)。
可以理解地，由于至少两层电子传输层130为ZnO薄膜，故而，此时可以将至少两层电子传输层130视为一层电子传输层130。
如图4所示，曲线a(虚线所示)为第一发光器件112正面的出光强度随至少两层电子传输层130的厚度之和(也即是ZnO薄膜厚度)的变化曲线，曲线b(实线所示)为第二发光器件114正面的出光强度随至少两层电子传输层130的厚度之和(也即是ZnO薄膜厚度)的变化曲线。
由图4可以看出，对于第一发光器件112和第二发光器件114而言，正面的出光强度随至少两层电子传输层130的厚度之和的变化曲线并不相同。如图4中曲线a所示，第一发光器件112在ZnO薄膜厚度为45nm左右以及190nm左右时，正面的出光强度较高。如图4中曲线b所示，第二发光器件114在ZnO薄膜厚度为20nm左右以及150nm左右时，正面的出光强度较高。
但是，ZnO薄膜的厚度(也即是至少两层电子传输层130的厚度之和)过大或者过小，都会影响发光器件110的电学性能。
示例的，ZnO薄膜的厚度过小，会导致发光器件110的电流过大，电流效率(电流效率＝发光亮度/电流密度)降低。相反，ZnO薄膜的厚度过大，会导致发光器件的启亮电压升高，电流降低，亮度降低，影响发光器件110的性能。
故而，需要综合发光器件110的光学特性以及电学特性，来设置至少两层电子传输层130的厚度之和的取值范围。
在一些实施例中，至少两层电子传输层130的厚度之和的取值范围为5nm～150nm。
可以理解地，至少两层电子传输层130中，各个电子传输层130的厚度可以相同，也可以不同。
在一些示例中，至少两层电子传输层130的厚度之和的取值范围为 10nm～130nm、20nm～120nm、50nm～100nm等。示例的，至少两层电子传输层130的厚度之和的取值可以为20nm、50nm、70nm、90nm或者130nm等。
可以理解地，设置至少两层电子传输层130的厚度之和的取值范围为5nm～150nm，避免至少两层电子传输层130的厚度之和过小(例如小于5nm)，导致发光器件110的电流过大，电流效率降低。并且，还能够避免至少两层电子传输层130的厚度过大(例如大于150nm)导致发光器件110的启亮电压升高，电流降低，亮度降低，影响发光器件110的性能。
可以理解地，设置至少两层电子传输层130的厚度之和的取值范围为5nm～150nm，能够在提高发光器件110的发光效率的基础上，满足不同的使用需求。
在一些实施例中，至少两层电子传输层130的厚度之和的取值范围为20nm～70nm。
示例的，至少两层电子传输层130的厚度之和的取值范围可以为25nm～65nm、30nm～60nm、40nm～55nm或者45nm～50nm等。示例的，至少两层电子传输层130的厚度的取值可以为35nm、45nm、55nm或者65nm等。
可以理解地，设置至少两层电子传输层130的厚度之和的取值范围为20nm～70nm，避免至少两层电子传输层130的厚度之和过小(例如小于20nm)，导致发光器件110的电流过大，电流效率降低。并且，还能够避免至少两层电子传输层130的厚度过大(例如大于70nm)导致发光器件110的启亮电压升高，电流降低，亮度降低，影响发光器件110的性能。
也即是，设置至少两层电子传输层130的厚度之和的取值范围为20nm～70nm，能够综合发光器件110的光学特性以及电学特性，来提高发光器件110的发光效率。
在一些实施例中，至少两层电子传输层130的厚度之和的取值范围为20nm～60nm。
示例的，至少两层电子传输层130的厚度之和的取值范围可以为25nm～55nm、30nm～50nm或者35nm～45nm等。示例的，至少两层电子传输层130的厚度的取值可以为22nm、30nm、35nm、45nm或者55nm等。
可以理解地，设置至少两层电子传输层130的厚度之和的取值范围为20nm～60nm，避免至少两层电子传输层130的厚度之和过小(例如小于20nm)，导致发光器件110的电流过大，电流效率降低。并且，还能够避免至少两层电子传输层130的厚度过大(例如大于60nm)导致发光器件110的启亮电压升高，电流降低，亮度降低，影响发光器件110的性能。
也即是，设置至少两层电子传输层130的厚度之和的取值范围为20nm～60nm，能够综合发光器件110的光学特性以及电学特性，来提高发光器件110的发光效率。
由上述可知，显示面板100还包括驱动背板150，多个发光器件110位于驱动背板150的一侧。并且，发光器件110为倒置结构，也即是第一电极122相对于第二电极124远离驱动背板150。
图5A为根据又一些实施例的显示面板的结构图。
在一些实施例中，如图5A所示，第一发光器件112包括第一部分第一电极122a，第二发光器件114包括第二部分第一电极122b。第一部分第一电极122a远离驱动背板150一侧的表面与驱动背板150之间的距离d1，大于第二部分第一电极122b远离驱动背板150一侧的表面与驱动背板150之间的距离d2。
示例的，多个发光器件110(包括第一发光器件112和第二发光器件114)的第一电极122为整层结构。第一部分第一电极122a和第二部分第一电极122b为整层的第一电极122中的一部分。
如图5A所示，由于第一发光器件112中的至少两层电子传输层130的厚度之和h1，大于第二发光器件114中的至少两层电子传输层130的厚度之和h2，使得第一部分第一电极122a远离驱动背板150一侧的表面与驱动背板150之间的距离d1，能够大于第二部分第一电极122b远离驱动背板150一侧的表面与驱动背板150之间的距离d2。
可以理解地，本公开的实施例中，以第一部分第一电极122a为例，第一部分第一电极122a远离驱动背板150一侧的表面与驱动背板150之间的距离d1，也即是第一部分第一电极122a远离驱动背板150一侧的表面，与驱动背板150中最远离衬底152的膜层(例如驱动电路层158)之间的距离。
如此设置，能够在提高不同颜色的发光器件110中，量子点发光层126中电子数量和空穴数量的一致性的基础上，使得不同发光器件110中第一电极122(例如第一部分第一电极122a和第二部分第一电极122b)的厚度能够相同或者近似相同，也即是使得整层第一电极122在不同位置处的厚度能够相同或者近似相同，提高了第一电极122向不同发光器件110中的量子点发光层126传输空穴数量的一致性，从而提高多个发光器件110的可靠性。
可以理解地，在另一些示例中，当发光器件110为正置结构，也即是第一电极122相对于第二电极124靠近驱动背板150时，类似地，第一发光器件112包括第一部分第二电极，第二发光器件114包括第二部分第二电极， 第一部分第二电极远离驱动背板150一侧的表面与驱动背板150之间的距离，大于第二部分第二电极远离驱动背板150一侧的表面与驱动背板之间的距离。
图5B为根据又一些实施例的显示面板的结构图。
在另一些示例中，如图5B所示，显示面板100还包括填充层128。填充层128至少位于第二部分第一电极122b远离驱动背板150的一侧表面。并且，填充层128远离驱动背板150一侧的表面，与第一部分第一电极122a远离驱动背板150一侧的表面平齐或者近似平齐，从而提高发光器件110的结构规整性。
在一些示例中，填充层128的材料包括氧化硅或者氮化硅等。
图6为根据一些实施例的第一发光器件的结构图。
在一些实施例中，如图6所示，第一发光器件112中的至少两层电子传输层130包括第一电子传输层131和第二电子传输层132。第二电子传输层132的电子迁移率小于第一电子传输层131的电子迁移率。
在一些示例中，如图6所示，第一电子传输层131相对于第二电子传输层132靠近第二电极124。在另一些示例中，第一电子传输层131相对于第二电子传输层132远离第二电极124。
可以理解地，设置第二电子传输层132的电子迁移率，小于第一电子传输层131的电子迁移率，能够减小至少两层电子传输层130整体的电子迁移率，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，提高发光器件110的发光效率。
图7A为根据一些实施例的第一电子传输层和第二电子传输层的能级关系图。图7B为根据另一些实施例的第一电子传输层和第二电子传输层的能级关系图。图7C为根据又一些实施例的第一电子传输层和第二电子传输层的能级关系图。图7D为根据又一些实施例的第一电子传输层和第二电子传输层的能级关系图。
在一些示例中，如图7A～图7D所示，第一电子传输层131的导带底能级CBM1(英文全称：Conduction Band Minimum，英文简称：CBM)，与第二电子传输层131的导带底能级CBM2不同。
如此设置，就能够在第一电子传输层131和第二电子传输层132之间形成电子传输势垒，阻碍电子向量子点发光层126传输，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图6所示，第一电子传输层131相对于第二电子传输 层132靠近第二电极124。此时，第一电子传输层131的导带底能级CBM1，小于第二电子传输层132的导带底能级CBM2。
也即是，如图7A和图7B所示，当第一电子传输层131相对于第二电子传输层132靠近第二电极124时，第一电子传输层131的导带底能级CBM1，小于第二电子传输层132的导带底能级CBM2，从而能够在第一电子传输层131和第二电子传输层132之间形成电子传输势垒，阻碍电子向量子点发光层126传输，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图7A所示，第一电子传输层131的价带顶能级VBM1(英文全称：Valance Band Maximum，英文简称：VBM)，大于第二电子传输层132的价带顶能级VBM2。在另一些示例中，如图7B所示，第一电子传输层131的价带顶能级VBM1，小于第二电子传输层132的价带顶能级VBM2。
在另一些示例中，第一电子传输层131相对于第二电子传输层132远离第二电极124。此时，第一电子传输层131的导带底能级CBM1，大于第二电子传输层132的导带底能级CBM2。
也即是，如图7C和图7D所示，当第一电子传输层131相对于第二电子传输层132远离第二电极124时，第一电子传输层131的导带底能级CBM1，大于第二电子传输层132的导带底能级CBM2，从而能够在第一电子传输层131和第二电子传输层132之间形成电子传输势垒，阻碍电子向量子点发光层126传输，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图7C所示，第一电子传输层131的价带顶能级VBM1，大于第二电子传输层132的价带顶能级VBM2。在另一些示例中，如图7B所示，第一电子传输层131的价带顶能级VBM1，小于第二电子传输层132的价带顶能级VBM2。
图8为根据一些实施例的发光器件的能级结构图。
在一些示例中，如图8所示，箭头g方向为能级(包括价带顶能级VBM和导带底能级CBM)增大的方向。箭头e -代表电子的迁移路径，箭头h +代表空穴的迁移路径。
第一发光器件112的第二电极124的材料为ITO，导带底能级CBM6为-4.7eV(英文全称：electron volt，中文名称：电子伏特)。
第一电子传输层131为ZnO薄膜，导带底能级CBM1为-4.1eV，价带顶能级VBM1为-7.3eV。
第二电子传输层132为ZnMgO(氧化镁锌)薄膜，导带底能级CBM2为-3.9eV，价带顶能级VBM2为-7.4eV。
红色量子点发光层(英文全称：Red Quantum Dot，英文简称：RQD)的材料为CdSe系量子点材料，导带底能级CBM7为-4.0eV，价带顶能级VBM7为-6.0eV。
第一空穴传输层1461为TCTA薄膜，导带底能级CBM8为-2.3eV，价带顶能级VBM8为-5.7eV。
第二空穴传输层1462为NPB薄膜，导带底能级CBM9为-2.4eV，价带顶能级VBM9为-5.4eV。
空穴注入层144为MoO 3薄膜，导带底能级CBM10为-6.0eV，价带顶能级VBM10为-9.0eV。
第一电极122材料为Mg和Ag(Mg和Ag的质量之比为2:8)，导带底能级CBM11为-4.1eV。
在一些实施例中，第一电子传输层131的材料包括ZnO(氧化锌)、GZO(氧化镓锌)、AZO(氧化铝锌)、IZO(氧化铟锌)、IGZO(氧化铟镓锌)和ZnMgO(氧化镁锌)中的任一个，第二电子传输层132的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，且第一电子传输层131的材料和第二电子传输层131的材料不同。
如此设置，使得第二电子传输层132的电子迁移率能够小于第一电子传输层131的电子迁移率，并且使得第一电子传输层131和第二电子传输层132之间能够形成电子传输势垒，阻碍电子向量子点发光层126传输，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
可以理解地，第一电子传输层131和第二电子传输层132也可以为其他n型氧化物薄膜。
在一些示例中，当第一电子传输层131相对于第二电子传输层132靠近量子点发光层126时，第一电子传输层131的材料包括ZnO，第二电子传输层的材料包括ZnMgO。
由上述可知，至少两层电子传输层130的厚度之和，影响量子点发光层126中电子的数量。可以理解地，至少两层电子传输层130中每一层电子传输层130的厚度，都会对量子点发光层126中电子的数量造成影响。
在一实施例中，如图6所示。第一电子传输层131的厚度h1大于0nm，且小于或等于60nm。和/或，第二电子传输层132的厚度h2大于0nm，且小 于或等于60nm。并且，第一电子传输层131的厚度h1，大于第二电子传输层132的厚度h2。
在一些示例中，第一电子传输层131的厚度h1大于0nm，且小于或等于55nm。在另一些示例中，第一电子传输层131的厚度h1大于0nm，且小于或等于45nm。在又一些示例中，第一电子传输层131的厚度h1大于0nm，且小于或等于35nm。
示例的，第一电子传输层131的厚度h1可以为15nm、25nm、35nm或者45nm等。
在一些示例中，第二电子传输层132的厚度h2大于0nm，且小于或等于55nm。在另一些示例中，第二电子传输层132的厚度h2大于0nm，且小于或等于45nm。在又一些示例中，第二电子传输层132的厚度h2大于0nm，且小于或等于35nm。
示例的，第二电子传输层132的厚度h2可以为15nm、25nm、35nm或者45nm等。
设置第一电子传输层131的厚度h1大于0nm，且小于或等于60nm，第二电子传输层132的厚度h2大于0nm，且小于或等于60nm，避免了第一电子传输层131和第二电子传输层132的厚度过大(例如第一电子传输层131或者第二电子传输层132大于60nm)，导致第一发光器件112的启亮电压升高，电流降低，亮度降低，影响第一发光器件112的性能。
并且，避免第一电子传输层131和第二电子传输层132的厚度过大(例如第一电子传输层131或者第二电子传输层132大于60nm)，还能够增大第一发光器件112的正面(远离驱动背板150)光线强度，减小第一发光器件112的侧面光线强度，提高第一发光器件112的出光率，增大第一发光器件112的亮度，降低显示面板100功耗。
此外，设置第一电子传输层131的厚度h1，大于第二电子传输层132的厚度h2，能够避免至少两层电子传输层130的厚度之和h过大，导致第一发光器件112的启亮电压升高，电流降低，亮度降低，影响第一发光器件112的性能。在一些实施例中，第一电子传输层131的厚度的取值范围为30nm～50nm。和/或，第二电子传输层132的厚度的取值范围为1nm～30nm。
在一些示例中，第一电子传输层131的厚度h1的取值范围可以为35nm～45nm或者30nm～40nm等。示例的，第一电子传输层131的厚度h1可以为35nm、40nm或者45nm等。
在一些示例中，第二电子传输层132的厚度h2的取值范围可以为 5nm～25nm或者10nm～20nm等。示例的，第二电子传输层132的厚度h2可以为5nm、10nm、15nm或者20nm等。
设置第一电子传输层131的厚度h1的取值范围为30nm～50nm，第二电子传输层132的厚度的取值范围为1nm～30nm，避免了第一电子传输层131的厚度h1或者第二电子传输层132的厚度h2过小(例如第一电子传输层131的厚度h1小于30nm，第二电子传输层132的厚度小于1nm)，导致第一发光器件112的电流过大，电流效率降低。
并且，还能够避免第一电子传输层131的厚度h1或第二电子传输层132的厚度h2过大(例如第一电子传输层131的厚度h1大于50nm，第二电子传输层132的厚度大于30nm)，导致第一发光器件112的启亮电压升高，电流降低，亮度降低，影响第一发光器件112的性能。
此外，避免第一电子传输层131的厚度h1或第二电子传输层132的厚度h2过大(例如第一电子传输层131的厚度h1大于50nm，第二电子传输层132的厚度大于30nm)，还能够增大第一发光器件112的正面(远离驱动背板150)光线强度，减小第一发光器件112的侧面光线强度，提高第一发光器件112的出光率，增大第一发光器件112的亮度，降低显示面板100功耗。
图9A为根据一些实施例的电流密度随电压的变化曲线图。图9B为根据一些实施例的发光亮度随电压的变化曲线图。图9C为根据一些实施例的外量子效率随电压的变化曲线图。
下面参照图9A～图9C，对本公开一些实施例中，第一发光器件112中第一电子传输层131和第二电子传输层132在不同厚度下，第一发光器件112的电流密度、发光亮度和外量子效率进行举例说明。
需要说明的是，图9A中，横坐标为电压(单位V)，纵坐标为电流密度(单位：毫安/平方厘米，mA/cm 2)。图9B中，横坐标为电压(单位V)，纵坐标为发光亮度(单位为坎德拉每平方米cd/m 2)。图9C中，横坐标为电压(单位V)，纵坐标为外量子效率(英文全称：External Quantum Efficiency，英文简称：EQE)。可以理解地，EQE＝出射的光子数/注入的电荷数。EQE越大，发光器件110的发光性能越好。
如图9A～图9C所示，组合1～组合4为不同厚度以及材料的电子传输层130的组合。
组合1中至少两层电子传输层130的材料均为ZnO(也可以视为一层电子传输层130)，ZnO薄膜的厚度为60nm。
组合2中第一电子传输层131的材料为ZnO，厚度为45nm。第二电子传 输层132的材料为ZnMgO，厚度为15nm。
组合3中第一电子传输层131的材料为ZnO，厚度为30nm。第二电子传输层132的材料为ZnMgO，厚度为30nm。
组合4中第一电子传输层131的材料为ZnMgO，厚度为15nm。第二电子传输层132的材料为ZnO，厚度为45nm。
示例的，组合2、组合3和组合4中，ZnMgO中Mg的摩尔百分比为5％。
如图9A～图9C所示，第一发光器件112选用双层的电子传输层130(包括第一电子传输层131和第二电子传输层132，例如组合2、组合3和组合4)时，电流密度、发光亮度以及EQE均优于选用单层的电子传输层130(组合1)，也即是，选用双层的电子传输层130时，第一发光器件112能够具有较好的发光性能。
可以理解地，由于选用双层的电子传输层130时，第一电子传输层131和第二电子传输层132中至少一个的材料为ZnMgO，通过Mg离子掺杂，能够起到阻挡电子的作用，降低第一电子传输层131或第二电子传输层132的电子迁移率，从而减小量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高第一发光器件112的发光效率。
此外，当第一电子传输层131的材料为ZnO，第二电子传输层132的材料为ZnMgO时，能够在第一电子传输层131和第二电子传输层132之间形成能级差，从而形成电子传输势垒，阻碍电子向量子点发光层126传输，平衡第一发光器件112中电子的传输能力和空穴的传输能力，从而提高第一发光器件112的发光效率。
如图9A和图9B所示，当电压增大时，选用组合2的第一发光器件112发光亮度增大，但是电流密度变化较小，使得电流效率(电流效率＝发光亮度/电流密度)能够增大，并且，如图9C所示，选用组合2时，第一发光器件112的外量子效率EQE增大，提高了第一发光器件112的性能。
如图9A和图9B所示，当电压增大时，选用组合3的第一发光器件112发光亮度较小，并且电流密度较小，导致电流效率较小，并且，如图9C所示，选用组合3时，第一发光器件112的外量子效率EQE较小，影响第一发光器件112的性能。
如图9A和图9B所示，当电压增大时，选用组合4的第一发光器件112的电流密度和发光亮度均增大，导致电流效率减小，并且，如图9C所示，选用组合4时，第一发光器件112的外量子效率EQE较小，影响第一发光器件112的性能。
也即是，当ZnMgO薄膜的厚度从20nm提升至40nm时，第一发光器件112的电流降低，发光亮度也降低，第一发光器件112的性能低于组合2(第一电子传输层131的材料为ZnO，厚度为45nm，第二电子传输层132的材料为ZnMgO，厚度为15nm)。
故而，在一些实施例中，第一电子传输层131的厚度大约为45nm。和/或，第二电子传输层132的厚度大约为15nm。
由上述可知，如此设置，能够提高第一发光器件112的电流效率以及外量子效率，从而提高第一发光器件112的发光性能。
可以理解地，本公开的实施例中，“大约”包括所阐述的值以及处于特定值的可接受偏差范围内的平均值，其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即，测量系统的局限性)所确定。
示例的，以第一电子传输层131为例，第一电子传输层131的厚度大约为45nm，也即是第一电子传输层131的厚度为45nm，并且能够在45nm的基础上，接受一定范围内(例如3％以内或者5％以内等)的偏差。
由上述可知，第二电子传输层132的材料包括ZnMgO。在一些实施例中，第二电子传输层132中，Mg的摩尔百分比大于0，且小于或等于50％。Mg的摩尔百分比与Zn的摩尔百分比之和为1。
可以理解地，第二电子传输层132的材料包括Zn 1-XMg XO，其中，X为Mg的摩尔百分比，1-X为Zn的摩尔百分比。
可以理解地，通过调节第二电子传输层132中Mg的摩尔百分比，能够对第二电子传输层132的电子迁移率、以及第二电子传输层132的能级(例如价带顶能级VBM和导带底能级CBM)起到调节作用，从而对传输至量子点发光层126中的电子数量起到调节作用，提高第一发光器件112中电子和空穴的传输平衡性，从而提高第一发光器件112的发光效率。
在一些示例中，Mg的摩尔百分比可以大于0，且小于或等于40％。在另一些示例中，Mg的摩尔百分比可以大于0，且小于或等于30％。在又一些示例中，Mg的摩尔百分比可以大于0，且小于或等于20％。
示例的，第二电子传输层132中Mg的摩尔百分比可以为10％、20％、30％或者40％等。
可以理解地，当第二电子传输层132中，Mg的摩尔百分比大于0，且小于或等于50％时，Zn的摩尔百分比大于或等于50％，且小于100％。
在一些实施例中，第二电子传输层132中，Mg的摩尔百分比的取值范围 为1％～20％。
在一些示例中，第二电子传输层132中，Mg的摩尔百分比的取值范围可以为2％～20％、5％～15％或者7％～12％等。示例的，第二电子传输层132中，Mg的摩尔百分比的取值可以为5％、8％、10％或者15％等。
可以理解地，通过调节第二电子传输层132中Mg的摩尔百分比，能够对第二电子传输层132的电子迁移率、以及第二电子传输层132的能级(例如价带顶能级VBM和导带底能级CBM)起到调节作用，从而对传输至量子点发光层126中的电子数量起到调节作用，提高第一发光器件112中电子和空穴的传输平衡性，从而提高第一发光器件112的发光效率。
可以理解地，当第二电子传输层132中，Mg的摩尔百分比的取值范围为1％～20％时，Zn的摩尔百分比的取值范围为80％～99％。
图10A为根据另一些实施例的电流密度随电压的变化曲线图。图10B为根据另一些实施例的发光亮度随电压的变化曲线图。图10C为根据另一些实施例的外量子效率随电压的变化曲线图。
下面参照图10A～图10C，对本公开一些实施例中，第一发光器件112中的第二电子传输层132中，Mg摩尔百分比不同时，第一发光器件112的电流密度、亮度和外量子效率进行举例说明。
需要说明的是，图10A中，横坐标为电压(单位V)，纵坐标为电流密度(单位：毫安/平方厘米，mA/cm 2)。图10B中，横坐标为电压(单位V)，纵坐标为发光亮度(单位为坎德拉每平方米cd/m 2)。图10C中，横坐标为电压(单位V)，纵坐标为外量子效率(英文全称：External Quantum Efficiency，英文简称：EQE)。可以理解地，EQE＝出射的光子数/注入的电荷数。EQE越大，发光器件110的发光性能越好。
如图10A～图10C所示，组合5～组合7为第二电子传输层132中Mg的摩尔百分比不同时，第二电子传输层132与第一电子传输层131的组合。
组合5中至少两层电子传输层130为ZnO(也可以视为一层电子传输层130)薄膜，ZnO薄膜的厚度为60nm。
组合6中第一电子传输层131为ZnO薄膜，厚度为45nm。第二电子传输层132为ZnMgO薄膜，厚度为15nm，其中，ZnMgO中Mg的摩尔百分比为5％。
组合7中第一电子传输层131为ZnO薄膜，厚度为45nm。第二电子传输层132为ZnMgO薄膜，厚度为15nm，其中，ZnMgO中Mg的摩尔百分比为8％。
如图10A～图10C所示，第一发光器件112选用双层的电子传输层130(包括第一电子传输层131和第二电子传输层132，例如组合6和组合7)时，电流密度、发光亮度以及EQE均优于选用单层的电子传输层130(组合5)，也即是，选用双层的电子传输层130时，第一发光器件112能够具有较好的发光性能。
如图10A和图10B所示，当电压增大时，选用组合6的第一发光器件112发光亮度增大，并且，如图10C所示，选用组合6时，第一发光器件112的外量子效率EQE增大，提高了第一发光器件112的性能。
如图10A和图10B所示，当电压增大时，选用组合7的第一发光器件112发光亮度较小，并且电流密度较小，导致电流效率较小，并且，如图10C所示，选用组合7时，第一发光器件112的EQE较小，影响第一发光器件112的性能。
可以理解地，如图10A～图10C所示，当第二电子传输层132中，Mg的摩尔百分比从5％提升至8％时，第一发光器件112的电流密度降低，但是发光亮度也大幅降低，导致第一发光器件112的电流效率和EQE降低。
也即是，当第一电子传输层131的材料为ZnO，厚度为45nm，第二电子传输层132的材料为ZnMgO，厚度为15nm，其中，ZnMgO中Mg的摩尔百分比为5％时，第一发光器件112具有较好的发光性能。
故而，在一些实施例中，第二电子传输层132中，Mg的摩尔百分比大约为5％。
由上述可知，如此设置，能够提高第一发光器件112的电流效率以及外量子效率，从而提高第一发光器件112的发光性能。
可以理解地，本公开的实施例中，“大约”包括所阐述的值以及处于特定值的可接受偏差范围内的平均值，其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即，测量系统的局限性)所确定。
示例的，以第二电子传输层132中，Mg的摩尔百分比为例，第二电子传输层132中，Mg的摩尔百分比大约为5％，也即是，第二电子传输层132中，Mg的摩尔百分比为5％，并且能够在5％的基础上，接收一定范围内(例如3％以内或者5％以内等)的偏差。
在一些示例中，当第一电子传输层131为ZnO薄膜，厚度为45nm，第二电子传输层132为ZnMgO薄膜，厚度为15nm，其中，ZnMgO中Mg的摩尔百分比为5％时，第一电子传输层131和第二电子传输层132的能级关系图如 图7A所示。
示例的，当第二电子传输层132为ZnO薄膜，厚度为45nm，第一电子传输层131为ZnMgO薄膜，厚度为15nm，其中，ZnMgO中Mg的摩尔百分比为5％时，第一电子传输层131和第二电子传输层132的能级关系图如图7D所示。
下面对发光器件110的制备方法进行举例说明。
在一些实现方式中，通常采用溶液法在第二电极124的一侧形成至少两层电子传输层130。示例的，采用溶液法形成至少两层电子传输层130，也即是，将形成电子传输层130的颗粒在溶剂中溶解，再将溶剂蒸发。
以采用ZnO薄膜作为电子传输层为例，示例的可以将ZnO颗粒溶解在乙醇中，将溶解后得到的溶剂涂覆(例如采用喷墨打印等方式)在第二电极124的一侧，并将乙醇挥发，得到ZnO薄膜。
本公开的发明人发现上述实现方式存下如下技术问题。
采用溶剂法制备得到的ZnO薄膜中，ZnO纳米颗粒存在大量的表面态(也即是ZnO纳米颗粒表面存在大量缺陷)。ZnO纳米颗粒中大量存在的表面态与量子点发光层126相互作用，捕获量子点发光层126中的电子，影响发光器件110的发光效率。
此外，当需要形成至少两层电子传输层130时，需要在形成一层电子传输层130之后，在该层电子传输层130远离第二电极124的一侧继续涂覆溶剂，以形成另一层电子传输层130。
为了便于描述，下面将先形成的电子传输层130定义为第一层电子传输层，将后形成的电子传输层130定义为第二层电子传输层。需要说明的是，第一层电子传输层和第二层电子传输层仅用于区分先形成的电子传输层130和后形成的电子传输层130，不对电子传输层130做进一步限定。
可以理解地，在形成第二层电子传输层时，需要将形成第二层电子传输层的溶剂，涂覆在已经形成的第一电子传输层远离第二电极124的一侧，这样一来，当形成第二层电子传输层的溶剂与形成第一层电子传输层的溶剂为非正交溶剂时，会导致形成第二层电子传输层的溶剂将已经形成的第一电子传输层再次溶解，造成已经形成的第一层电子传输层损坏，增大了至少两层电子传输层130的生产难度。
此外，采用溶剂法制备的ZnO薄膜中，ZnO为纳米颗粒状。示例的，ZnO纳米颗粒的直径约为5nm。这样一来，会导致ZnO薄膜的表面粗糙度(英文全称：Surface Roughness)较高。在一些示例中，采用溶剂法制备的ZnO薄 膜的RMS(英文全称：Root Mean Square，中文名称：均方根)表面粗糙度可以达到1nm～2nm。
并且，采用溶剂法制备的ZnO薄膜无法适配高分辨率显示，影响了显示面板100的显示性能。
基于此，本公开的实施例中，采用磁控溅射工艺，在第二电极124的一侧形成至少两层电子传输层130。
下面以第二电极124为ITO基板为例，对至少两层电子传输层130的制备方法进行举例说明。
在一些示例中，可以采用单靶溅射的方式形成第一电子传输层131。示例的，第一电子传输层131为ZnO薄膜。
示例的，使用去离子水、异丙醇分别超声清洗ITO基板15分钟，然后用氮气吹干，135℃烘烤干燥5分钟。使用紫外臭氧处理ITO基板10分钟，进一步清洗ITO基板表面附着的有机污染物，钝化ITO基板表面缺陷。
首先将清洗完毕的ITO基板传入磁控溅射腔室，当腔室气压达到5×10 -4Pa时开始通入氩气，氩气的流量为30sccm～60sccm(英文全称：Stard Liter Per Minute，中文名称：标准升/每分钟)，示例的，氩气的流量可以为40sccm～50sccm。将腔室气压保持在0.4Pa～1Pa范围内，示例的，腔室气压可以在0.5Pa～0.6Pa范围内。
射频源的功率设置为20W～150W，示例的，射频源的功率可以为50W～100W。射频源开启5分钟(也即是启辉5分钟)之后打开挡板，使目标靶材沉积在ITO基板上。设定工艺时间结束后，溅射停止，将ITO基板从工艺腔中取出，使得ITO基板上能够沉积ZnO薄膜作为第一电子传输层131。
在另一些示例中，可以采用多靶溅射的方式形成第二电子传输层132。示例的，第二电子传输层132为MgZnO薄膜。
在清洗ITO基板之后，将清洗完毕的ITO基板传入磁控溅射腔室，当腔室气压达到5×10 -4Pa时开始通入氩气，氩气的流量为30sccm～60sccm(英文全称：Stard Liter Per Minute，中文名称：标准升/每分钟)，示例的，氩气的流量可以为40sccm～50sccm。将腔室气压保持在0.4Pa～1Pa范围内，示例的，腔室气压可以在0.5Pa～0.6Pa范围内。
第一个射频源的功率设置为20W～150W，示例的，第一个射频源的功率可以为50W～100W。第二个射频源的功率设置为20W～150W，示例的，第二个射频源的功率可以为50W～100W。
第一个射频源和第二个射频源开启5分钟(也即是启辉5分钟)之后打 开第一个射频源和第二个射频源的靶挡板，使目标靶材沉积在ITO基板上。可以理解地，第一个射频源可以用于溅射ZnO，第二个射频源可以用于溅射MgO，使得Mg离子和Zn离子能够在ITO基板上沉积，形成MgZnO薄膜。
设定工艺时间结束后，溅射停止，将ITO基板从工艺腔中取出，使得ITO基板上能够沉积MgZnO薄膜作为第二电子传输层132。示例的，第二电子传输层132可以沉积在第一电子传输层131远离第二电极124的一侧。
可以理解地，通过控制溅射工艺时间、工艺腔室气压、以及射频源功率等，能够对沉积在ITO基板上的薄膜厚度起到控制作用。示例的，溅射工艺时间越长，薄膜厚度越厚。溅射功率越高，Ar离子轰击较强，则薄膜中颗粒(例如ZnO纳米颗粒或者MgZnO纳米颗粒)的尺寸增加，薄膜沉积速率增加。溅射气压增加，原子自由程降低，Ar离子能量减弱，轰击变弱，导致薄膜结晶度降低，生长速率降低。
可以理解地，通过重复上述步骤，即可得到层叠设置的至少两层电子传输层130。
可以理解地，采用磁控溅射的方式形成至少两层电子传输层130，一方面，能够减小电子传输层130中氧化物(例如ZnO)的表面态，从而减小电子传输层130中的氧化物与量子点发光层126之间相互作用，有利于降低界面缺陷引起的非辐射复合(例如俄歇复合)损失，提高发光器件110的发光效率。
另一方面，能够减小在后形成的电子传输层130，对在先形成的电子传输层130造成的影响，不易破坏在先形成的电子传输层130，从而能够灵活控制至少两层电子传输层130的厚度以及材料等，从而能够灵活控制第一发光器件112的光学特性以及电学特性，提高第一发光器件112中电子迁移率和空穴迁移率的一致性，均衡第一发光器件112中电子和空穴的传输能力，从而提高量子点发光层126中电子数量和空穴数量的一致性，提高第一发光器件112的发光效率。
再一方面，以第一电子传输层131为ZnO薄膜为例，采用磁控溅射工艺形成的ZnO薄膜中，ZnO不会或者仅仅少会量呈纳米颗粒状，从而，能够降低ZnO薄膜的表面粗糙度。在一些示例中，采用磁控溅射工艺形成的ZnO薄膜，RMS表面粗糙度可减小到0.5nm左右，提高发光器件110的发光性能。
又一方面，采用磁控溅射工艺形成至少两层电子传输层130，还能够匹配高分辨率显示，并且工艺简单，能够与驱动背板150的制备工艺适配，提高显示面板100的显示性能，降低显示面板100的生产成本。
下面以第一发光器件112为例，对发光器件110的制备方法进行举例说 明。
由上述可知，可以采用磁控溅射工艺，在ITO基板上形成电子传输层130。
示例的，在形成层叠设置的双层电子传输层130(包括第一电子传输层131和第二电子传输层132)时，可以将第一个射频源的功率设置为20W～150W，示例的，第一个射频源的功率可以为50W～100W。可以将第二个射频源的功率设置为20W～150W，示例的，第二个射频源的功率可以为50W～100W。
第一个射频源和第二个射频源开启5分钟(也即是启辉5分钟)之后打开第一个射频源的靶挡板，使第一电子传输层131沉积在在ITO基板上。示例的，第一个射频源可以用于溅射ZnO。5分钟～15分钟后，打开第二个射频源的靶挡板，第一个射频源和第二个射频源共溅射，使得第二电子传输层132沉积在第一电子传输层131远离ITO基板(也即是第二电极124)的一侧。
可以理解地，第二个射频源可以用于溅射MgO，第一个射频源和第二个射频源共溅射，使得Mg离子和Zn离子能够在ITO基板上沉积，形成MgZnO薄膜。5分钟～15分钟后，停止溅射。将沉积至少两层电子传输层130后的ITO基板从工艺腔中取出。
示例的，在形成第一电子传输层131和第二电子传输层132之后，可以采用旋涂的方式，在第二电子传输层132远离第一电子传输层131的一侧涂覆红色CdSe系量子点溶液。而后在加热平台或者烘箱中烘烤，烘烤的温度范围为80℃～150℃，烘烤时间为5分钟～30分钟。示例的，可以控制加热平台的温度为120℃，烘烤10分钟，以在至少两层电子传输层130远离第二电极124的一侧形成量子点发光层126。
将带有上述膜层的基板(第二电极124、至少两层电子传输层130和量子点发光层126)放入蒸镀机中，在5×10 -4Pa～4×10 -5Pa的真空度下，热蒸发沉积空穴传输层146、空穴注入层144以及第一电极122。
在一些示例中，在形成第一电极122之后，可以采用玻璃板覆盖第一电极122，并在第一电极122和玻璃板之间设置封装胶，通过紫外线照射的方式使封装固化，起到保护发光器件110(第一发光器件112)的作用。
在一些实施例中，如图3A～图3C所示，显示面板100还包括第三发光器件116。第三发光器件116用于发射第三颜色光。第二颜色光的波长，大于第三颜色光的波长。
示例的，第三颜色光为蓝光(波长约为400nm～470nm)。
可以理解地，可以理解地，第二发光器件114中的量子点1261的量子点 核的尺寸，大于第三发光器件116中的量子点1261的量子点核的尺寸。
通过调节不同发光器件110(第一发光器件112、第二发光器件114和第三发光器件116)中，量子点1261中的量子点核的尺寸，使得第一发光器件112、第二发光器件114和第三发光器件116能够发射出不同颜色的光，从而使得显示面板100能够实现全彩化图像显示。
在一些实施例中，第一发光器件112中电子传输层的数量，小于第三发光器件116中电子传输层的数量。
可以理解地，通过调节电子传输层130的数量，能够对传输至量子点发光层126中的电子数量起到调节所用。
故而，设置第一发光器件112中电子传输层130的数量，小于第三发光器件116中电子传输层130的数量，也即是，根据发光器件110的发光颜色(发光波长)，有针对性地设置不同数量的电子传输层130。
这样一来，就能够分别调节不同颜色的发光器件110中，量子点发光层126中的电子数量，有针对性地提高不同颜色的发光器件110中，量子点发光层126中电子数量和空穴数量的一致性，从而有针对性地提高不同颜色发光器件110的发光效率，延长不同颜色发光器件110的使用寿命。
由上述可知，第一发光器件112中电子传输层130的数量，小于第二发光器件114中电子传输层130的数量。在一些示例中，如图3A～图3C所示，第二发光器件114中电子传输层130的数量，与第三发光器件116中电子传输层的数量相等。
由上述可知，第二电极124相对于第一电极122远离驱动背板150。在一些示例中，如图5A所示，第三发光器件116包括第三部分第一电极122c。示例的，多个发光器件110(包括第一发光器件112、第二发光器件114和第三发光器件116)的第一电极122为整层结构。第三部分第一电极122c为整层的第一电极122中的一部分。
第二部分第一电极122b远离驱动背板150一侧的表面与驱动背板150之间的距离d2，与第三部分第一电极122c远离驱动背板150一侧的表面与驱动背板150之间的距离d3相同或者近似相同。
如此设置，使得不同发光器件110中第一电极122(例如第二部分第一电极122b和第三部分第一电极122c)的厚度能够相同或者近似相同，也即是使得整层第一电极122在不同位置处的厚度能够相同或者近似相同，提高了第一电极122向不同发光器件110中的量子点发光层126传输空穴数量的一致性，从而提高多个发光器件110的可靠性。
在一些示例中，如图5B所示，填充层128还位于第三部分第一电极122c远离驱动背板150的一侧表面。填充层128远离驱动背板150一侧的表面，与第一部分第一电极122a远离驱动背板150一侧的表面平齐或者近似平齐，从而提高发光器件110的结构规整性。
图11为根据一些实施例的第二发光器件和第三发光器件的结构图。
在一些实施例中，如图11所示，第二发光器件114和第三发光器件116中，至少一个发光器件110的至少两层电子传输层130包括第三电子传输层133、第四电子传输层134和第五电子传输层135。
在一些示例中，如图11所示，第二发光器件114和第三发光器件116均包括第三电子传输层133、第四电子传输层134和第五电子传输层135。
在一些示例中，第四电子传输层134的电子迁移率，小于第三电子传输层133的电子迁移率。且第四电子传输层134的电子迁移率，小于第五电子传输层135的电子迁移率。
如此设置，能够减小至少两层电子传输层130整体的电子迁移率，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，提高发光器件110的发光效率。
在一些示例中，第三电子传输层133的电子迁移率，和第五电子传输层135的电子迁移率相同或者近似相同。
图12A为根据一些实施例的第三电子传输层、第四电子传输层和第五电子传输层的能级关系图。图12B为根据另一些实施例的第三电子传输层、第四电子传输层和第五电子传输层的能级关系图。
在一些实施例中，如图11所示，第三电子传输层133、第四电子传输层134和第五电子传输层135沿第二电极124至量子点发光层126的方向，依次远离第二电极124。
如图12A和图12B所示，第三电子传输层133的导带底能级CBM3，小于第四电子传输层134的导带底能级CBM4。或，第四电子传输层134的导带底能级CBM4，小于第五电子传输层135的导带底能级CBM5。
由于第三电子传输层133、第四电子传输层134和第五电子传输层135沿第二电极124至量子点发光层126的方向，依次远离第二电极124，故而，如图12A所示，设置第三电子传输层133的导带底能级CBM3，小于第四电子传输层134的导带底能级CBM4，能够在第三电子传输层133和第四电子传输层134之间形成电子传输势垒。
或者，如图12B所示，设置第四电子传输层134的导带底能级CBM4， 小于第五电子传输层135的导带底能级CBM5，能够在第四电子传输层134和第五电子传输层135之间形成电子传输势垒。
这样一来，就能够阻碍电子向量子点发光层126传输，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图12A所示，第四电子传输层134的价带顶能级VBM4，小于第三电子传输层133的价带顶能级VBM3。并且，第四电子传输层134的价带顶能级VBM4，小于第五电子传输层135的价带顶能级VBM5。
在另一些示例中，如图12B所示，第四电子传输层134的价带顶能级VBM4，大于第三电子传输层133的价带顶能级VBM3。并且，第四电子传输层134的价带顶能级VBM4，大于第五电子传输层135的价带顶能级VBM5。
在一些实施例中，如图12A和图12B所示，第三电子传输层133的导带底能级CBM3，与第五电子传输层135的导带底能级CBM5相等。
在一些示例中，可以设置第三电子传输层133和第五电子传输层135的材料相同，使得第三电子传输层133的导带底能级CBM3，与第五电子传输层135的导带底能级CBM5能够相等，提高发光器件110(例如第二发光器件114和第三发光器件116)的加工便捷性。
在一些示例中，如图12A和图12B所示，第三电子传输层133的价带顶能级VBM3，与第五电子传输层135的价带顶能级VBM5相等。
图12C为根据一些实施例的第六电子传输层、第七电子传输层、第八电子传输层和第九电子传输层的能级关系图。图12D为根据一些实施例的第六电子传输层、第七电子传输层、第八电子传输层、第九电子传输层和第十电子传输层的能级关系图。
在一些实施例中，如图12C所示，多个发光器件110中的任一个发光器件110(例如第一发光器件112、第二发光器件114和第三发光器件116)包括第六电子传输层136、第七电子传输层137、第八电子传输层138和第九电子传输层139。
在一些示例中，第六电子传输层136、第七电子传输层137、第八电子传输层138和第九电子传输层139沿第二电极124至量子点发光层126的方向，依次远离第二电极124。
在一些示例中，如图12C所示，第六电子传输层136的导带底能级CBM12，大于第七电子传输层137的导带底能级CBM13。第七电子传输层137的导带底能级CBM13，小于第八电子传输层138的导带底能级CBM14。 第八电子传输层138的导带底能级CBM14，大于第九电子传输层139的导带底能级CBM15。
如此设置，使得第六电子传输层136、第七电子传输层137、第八电子传输层138和第九电子传输层139之间能够形成电子传输势垒，阻碍电子向量子点发光层126传输，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图12C所示，第六电子传输层136的价带顶能级VBM12，小于第七电子传输层137的价带顶能级VBM13。第七电子传输层137的价带顶能级VBM13，大于第八电子传输层138的价带顶能级VBM14。第八电子传输层138的价带顶能级VBM14，小于第九电子传输层139的价带顶能级VBM15。
在另一些示例中，如图12D所示，多个发光器件110中的任一个发光器件110(例如第一发光器件112、第二发光器件114和第三发光器件116)包括第六电子传输层136、第七电子传输层137、第八电子传输层138和第九电子传输层139和第十电子传输层141。
在一些示例中，第六电子传输层136、第七电子传输层137、第八电子传输层138、第九电子传输层139和第十电子传输层141沿第二电极124至量子点发光层126的方向，依次远离第二电极124。
在一些示例中，如图12D所示，第六电子传输层136的导带底能级CBM12，大于第七电子传输层137的导带底能级CBM13。第七电子传输层137的导带底能级CBM13，小于第八电子传输层138的导带底能级CBM14。第八电子传输层138的导带底能级CBM14，大于第九电子传输层139的导带底能级CBM15。第九电子传输层139的导带底能级CBM15，小于第十电子传输层141的导带底能级CBM16。
如此设置，使得第六电子传输层136、第七电子传输层137、第八电子传输层138、第九电子传输层139和第十电子传输层141之间能够形成电子传输势垒，阻碍电子向量子点发光层126传输，减少量子点发光层126中电子的数量，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，如图12D所示，第六电子传输层136的价带顶能级VBM12，小于第七电子传输层137的价带顶能级VBM13。第七电子传输层137的价带顶能级VBM13，大于第八电子传输层138的价带顶能级VBM14。 第八电子传输层138的价带顶能级VBM14，小于第九电子传输层139的价带顶能级VBM15。第九电子传输层139的价带顶能级VBM15，大于第十电子传输层146的价带顶能级VBM16。
由上述可知，在一些示例中，可以采用磁控溅射工艺，形成至少两层电子传输层130。下面对第三电子传输层133、第四电子传输层134和第五电子传输层135的制备方法进行举例说明。
在一些示例中，在形成层叠设置的三层电子传输层130(包括第三电子传输层133、第四电子传输层134和第五电子传输层135)时，可以将第一个射频源的功率设置为20W～150W，示例的，第一个射频源的功率可以为50W～100W。可以将第二个射频源的功率设置为20W～150W，示例的，第二个射频源的功率可以为50W～100W。
第一个射频源和第二个射频源开启5分钟(也即是启辉5分钟)之后打开第一个射频源的靶挡板，使第三电子传输层133沉积在在ITO基板上。示例的，第一个射频源可以用于溅射ZnO，第三电子传输层133为ZnO薄膜。5分钟～15分钟后，打开第二个射频源的靶挡板，第一个射频源和第二个射频源共溅射，使得第四电子传输层134沉积在第三电子传输层133远离ITO基板(也即是第二电极124)的一侧。可以理解地，第二个射频源可以用于溅射MgO，第一个射频源和第二个射频源共溅射，使得Mg离子和Zn离子能够在ITO基板上沉积，形成MgZnO薄膜。
可以理解地，通过调节第一个射频源和第二个射频源的功率，能够对第四电子传输层134中，不同元素的含量比起到控制作用，满足不同的使用需求。
5分钟～15分钟后，关闭第二个射频源，第一个射频源继续溅射，以在第四电子传输层134远离第三电子传输层133的一侧形成第五电子传输层135。第五电子传输层135为ZnO薄膜。5分钟～15分钟后，停止溅射。将沉积至少两层电子传输层130后的ITO基板从工艺腔中取出。
在另一些示例中，在形成层叠设置的三层电子传输层130(包括第三电子传输层133、第四电子传输层134和第五电子传输层135)时，可以将第一个射频源的功率设置为20W～150W，示例的，第一个射频源的功率可以为50W～100W。可以将第二个射频源的功率设置为20W～150W，示例的，第二个射频源的功率可以为50W～100W。
第一个射频源和第二个射频源开启5分钟(也即是启辉5分钟)之后打开第一个射频源的靶挡板，使第三电子传输层133沉积在在ITO基板上。示 例的，第一个射频源可以用于溅射ZnO，第三电子传输层133为ZnO薄膜。
5分钟～15分钟后，关闭第一个射频源，打开第二个射频源的靶挡板，使得第四电子传输层134沉积在第三电子传输层133远离ITO基板(也即是第二电极124)的一侧。可以理解地，第二个射频源可以用于溅射MgZnO，第四电子传输层134为MgZnO薄膜。
5分钟～15分钟后，关闭第二个射频源，打开第一个射频源继续溅射，以在第四电子传输层134远离第三电子传输层133的一侧形成第五电子传输层135。第五电子传输层135为ZnO薄膜。5分钟～15分钟后，停止溅射。将沉积至少两层电子传输层130后的ITO基板从工艺腔中取出。
示例的，采用上述方式，也可以形成层叠设置的四层、五层、六层或者更至少两层电子传输层130。
图13为根据另一些实施例的发光器件的能级结构图。
在一些示例中，如图13所示，箭头g方向为能级(包括价带顶能级VBM和导带底能级CBM)增大的方向。箭头e -代表电子的迁移路径，箭头h +代表空穴的迁移路径。
以第二发光器件114为例，第二发光器件114的第二电极124的材料为ITO，导带底能级CBM6为-4.7eV。
第三电子传输层133为ZnO薄膜，导带底能级CBM3为-4.1eV，价带顶能级VBM3为-7.3eV。
第四电子传输层134为ZnMgO薄膜，导带底能级CBM4为-3.9eV，价带顶能级VBM4为-7.4eV。
第五电子传输层135为ZnO薄膜，导带底能级CBM5为-4.1eV，价带顶能级VBM5为-7.3eV。
绿色量子点发光层(英文全称：Green Quantum Dot，英文简称：GQD)的材料为CdSe系量子点材料，导带底能级CBM17为-3.9eV，价带顶能级VBM17为-6.3eV。
第一空穴传输层1461的为TCTA薄膜，导带底能级CBM8为-2.3eV，价带顶能级VBM8为-5.7eV。
第二空穴传输层1462的为NPB薄膜，导带底能级CBM9为-2.4eV，价带顶能级VBM9为-5.4eV。
空穴注入层144的为MoO 3薄膜，导带底能级CBM10为-6.0eV，价带顶能级VBM10为-9.0eV。
第一电极122材料为Mg和Ag(Mg和Ag的质量之比为2:8)，导带底 能级CBM11为-4.1eV。
在一些实施例中，第三电子传输层133的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。第四电子传输层134的材料ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。五电子传输层135的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个。且第四电子传输层134的材料与第三电子传输层133的材料不同。和/或，第四电子传输层134的材料与第五电子传输层135的材料不同。
如此设置，使得第四电子传输层134的电子迁移率能够小于第三电子传输层133的电子迁移率，并且，使得第四电子传输层134的电子迁移率能够小于第五电子传输层135的电子迁移率。
此外，使得第三电子传输层133、第四电子传输层134和第五电子传输层135之间能够形成电子传输势垒，阻碍电子向量子点发光层126传输，提高量子点发光层126中电子数量和空穴数量的一致性，从而提高发光器件110的发光效率。
在一些示例中，当第三电子传输层133、第四电子传输层134和第五电子传输层135沿第二电极124至量子点发光层126的方向，依次远离第二电极124时，第三电子传输层133的材料包括ZnO，第四电子传输层134的材料包括ZnMgO，第五电子传输层135的材料包括ZnO。
可以理解地，第三电子传输层133、第四电子传输层134和第五电子传输层135也可以为其他n型氧化物薄膜。
由上述可知，至少两层电子传输层130中每一层电子传输层130的厚度，都会对量子点发光层126中电子的数量造成影响。
在一实施例中，如图11所示，当第二发光器件114包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第三电子传输层133的厚度h23大于0nm，且小于或等于40nm。第四电子传输层134的厚度h24大于0nm，且小于或等于30nm。第五电子传输层135的厚度h25大于0nm，且小于或等于40nm。
可以理解地，在第二发光器件114中，第三电子传输层133的厚度h23、第四电子传输层134的厚度h24和第五电子传输层135的厚度h25可以相同，也可以不同。
在一些示例中，第三电子传输层133的厚度h23大于0nm，且小于或等于35nm。在另一些示例中，第三电子传输层133的厚度h23大于0nm，且小于或等于30nm。在又一些示例中，第三电子传输层133的厚度h23大于0nm， 且小于或等于25nm。
示例的，第三电子传输层133的厚度h23可以为15nm、20nm、25nm或者35nm等。
在一些示例中，第四电子传输层134的厚度h24大于0nm，且小于或等于25nm。在另一些示例中，第四电子传输层134的厚度h24大于0nm，且小于或等于20nm。在又一些示例中，第四电子传输层134的厚度h24大于0nm，且小于或等于15nm。
示例的，第四电子传输层134的厚度h24可以为15nm、20nm、25nm或者28nm等。
在一些示例中，第五电子传输层135的厚度h25大于0nm，且小于或等于35nm。在另一些示例中，第五电子传输层135的厚度h25大于0nm，且小于或等于30nm。在又一些示例中，第五电子传输层135的厚度h25大于0nm，且小于或等于25nm。
示例的，第五电子传输层135的厚度h25可以为15nm、20nm、25nm或者35nm等。
可以理解地，在第二发光器件114中，第三电子传输层133的厚度h23大于0nm，且小于或等于40nm，第四电子传输层134的厚度h24大于0nm，且小于或等于30nm，第五电子传输层135的厚度h25大于0nm，且小于或等于40nm，避免了第三电子传输层133、第四电子传输层134或者第五电子传输层135的厚度过大(例如第三电子传输层133的厚度h23大于40nm、第四电子传输层134的厚度h24大于30nm或者第五电子传输层135的厚度h25大于40nm)，导致第二发光器件114的启亮电压升高，电流降低，亮度降低，影响第二发光器件114的性能。
并且，避免第三电子传输层133、第四电子传输层134或者第五电子传输层135的厚度过大(例如第三电子传输层133的厚度h23大于40nm、第四电子传输层134的厚度h24大于30nm或者第五电子传输层135的厚度h25大于40nm)，还能够增大第二发光器件114的正面(远离驱动背板150)光线强度，使得第二发光器件114的正面出光能够近似呈朗伯分布，减小第二发光器件114的侧面光线强度，提高第二发光器件114的出光率，增大第二发光器件114的亮度，降低显示面板100功耗。
在一些实施例中，当第三发光器件116包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第三电子传输层133的厚度大于0nm，且小于或等于30nm。第四电子传输层134的厚度大于0nm，且小于或等于 20nm。第五电子传输层135的厚度大于0nm，且小于或等于30nm。
可以理解地，在第三发光器件116中，第三电子传输层133的厚度h33、第四电子传输层134的厚度h34和第五电子传输层135的厚度h35可以相同，也可以不同。
在一些示例中，第三电子传输层133的厚度h33大于0nm，且小于或等于25nm。在另一些示例中，第三电子传输层133的厚度h33大于0nm，且小于或等于20nm。在又一些示例中，第三电子传输层133的厚度h33大于0nm，且小于或等于15nm。
示例的，第三电子传输层133的厚度h33可以为15nm、20nm、25nm或者28nm等。
在一些示例中，第四电子传输层134的厚度h34大于0nm，且小于或等于15nm。在另一些示例中，第四电子传输层134的厚度h34大于0nm，且小于或等于10nm。在又一些示例中，第四电子传输层134的厚度h34大于0nm，且小于或等于5nm。
示例的，第四电子传输层134的厚度h34可以为10nm、12nm、15nm或者18nm等。
在一些示例中，第三电子传输层135的厚度h35大于0nm，且小于或等于25nm。在另一些示例中，第三电子传输层135的厚度h35大于0nm，且小于或等于20nm。在又一些示例中，第三电子传输层135的厚度h35大于0nm，且小于或等于15nm。
示例的，第三电子传输层135的厚度h35可以为15nm、20nm、25nm或者28nm等。
可以理解地，设置第三发光器件116中，第三电子传输层133的厚度h33大于0nm，且小于或等于30nm，第四电子传输层134的厚度h34大于0nm，且小于或等于20nm，第五电子传输层135的厚度h35大于0nm，且小于或等于30nm，避免了第三电子传输层133、第四电子传输层134或者第五电子传输层135的厚度过大(例如第三电子传输层133的厚度h33大于30nm、第四电子传输层134的厚度h34大于20nm或者第五电子传输层135的厚度h35大于30nm)，导致第三发光器件116的启亮电压升高，电流降低，亮度降低，影响第三发光器件116的性能。
并且，避免第三电子传输层133、第四电子传输层134或者第五电子传输层135的厚度过大(例如第三电子传输层133的厚度h33大于30nm、第四电子传输层134的厚度h34大于20nm或者第五电子传输层135的厚度h35大于 30nm)，还能够增大第三发光器件116的正面(远离驱动背板150)光线强度，使得第三发光器件116的正面出光能够近似呈朗伯分布，减小第三发光器件116的侧面光线强度，提高第三发光器件116的出光率，增大第三发光器件116的亮度，降低显示面板100功耗。
在一些实施例中，当第二发光器件114包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第三电子传输层133的厚度h23的取值范围为5nm～20nm，第四电子传输层134的厚度h24的取值范围为1nm～15nm，第五电子传输层135的厚度h25的取值范围为5nm～20nm。
在一些示例中，第三电子传输层133的厚度h23的取值范围可以为8nm～18nm或者5nm～15nm等。示例的，第三电子传输层133的厚度h23的取值范围可以为6nm、10nm、15nm或者18nm等。
在一些示例中，第四电子传输层134的厚度h24的取值范围可以为1nm～12nm或者1nm～10nm等。示例的，第三电子传输层133的厚度h23的取值范围可以为3nm、8nm或者12nm等。
在一些示例中，第五电子传输层135的厚度h25的取值范围可以为8nm～18nm或者5nm～15nm等。示例的，第五电子传输层135的厚度h25的取值范围可以为6nm、10nm、15nm或者18nm等。
可以理解地，在第二发光器件114中，设置第三电子传输层133的厚度h23的取值范围为5nm～20nm，第四电子传输层134的厚度h24的取值范围为1nm～15nm，第五电子传输层135的厚度h25的取值范围为5nm～20nm，避免了第三电子传输层133的厚度h23、第四电子传输层134的厚度h24或者第五电子传输层135的厚度h25过小(例如第三电子传输层133的厚度h23小于5nm、第四电子传输层134的厚度h24小于1nm或者第五电子传输层135的厚度h25小于5nm)，导致第二发光器件114的电流过大，电流效率降低。
并且，还能够避免第三电子传输层133的厚度h23、第四电子传输层134的厚度h24或者第五电子传输层135的厚度h25过大(例如第三电子传输层133的厚度h23大于20nm、第四电子传输层134的厚度h24大于15nm或者第五电子传输层135的厚度h25大于20nm)，导致第二发光器件114的启亮电压升高，电流降低，亮度降低，影响第一发光器件112的性能。
此外，避免第三电子传输层133的厚度h23、第四电子传输层134的厚度h24或者第五电子传输层135的厚度h25过大(例如第三电子传输层133的厚度h23大于20nm、第四电子传输层134的厚度h24大于15nm或者第五电子传输层135的厚度h25大于20nm)，还能够增大第二发光器件114的正面(远 离驱动背板150)光线强度，减小第二发光器件114的侧面光线强度，提高第一发光器件112的出光率，增大第二发光器件114的亮度，降低显示面板100功耗。
在一些实施例中，当第三发光器件116包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第三电子传输层133的厚度h33的取值范围为5nm～15nm，第四电子传输层134的厚度h34的取值范围为1nm～15nm，第五电子传输层135的厚度h35的取值范围为5nm～15nm。
在一些示例中，第三电子传输层133的厚度h33的取值范围可以为6nm～13nm或者8nm～10nm等。示例的，第三电子传输层133的厚度h33的取值范围可以为6nm、8nm、9nm或者12nm等。
在一些示例中，第四电子传输层134的厚度h34的取值范围可以为1nm～10nm或者1nm～5nm等。示例的，第三电子传输层133的厚度h33的取值范围可以为3nm、8nm、10nm或者12nm等。
在一些示例中，第五电子传输层135的厚度h35的取值范围可以为6nm～13nm或者8nm～10nm等。示例的，第五电子传输层135的厚度h35的取值范围可以为6nm、8nm、9nm或者12nm等。
可以理解地，在第三发光器件116中，设置第三电子传输层133的厚度h33的取值范围为5nm～15nm，第四电子传输层134的厚度h34的取值范围为1nm～15nm，第五电子传输层135的厚度h35的取值范围为5nm～15nm，避免了第三电子传输层133的厚度h33、第四电子传输层134的厚度h34或者第五电子传输层135的厚度h35过小(例如第三电子传输层133的厚度h33小于5nm、第四电子传输层134的厚度h34小于1nm或者第五电子传输层135的厚度h35小于5nm)，导致第一发光器件112的电流过大，电流效率降低。
并且，还能够避免第三电子传输层133的厚度h33、第四电子传输层134的厚度h34或者第五电子传输层135的厚度h35过大(例如第三电子传输层133的厚度h33大于15nm、第四电子传输层134的厚度h34大于15nm或者第五电子传输层135的厚度h35大于15nm)，导致第一发光器件112的启亮电压升高，电流降低，亮度降低，影响第一发光器件112的性能。
此外，避免第三电子传输层133的厚度h33、第四电子传输层134的厚度h34或者第五电子传输层135的厚度h35过大(例如第三电子传输层133的厚度h33大于15nm、第四电子传输层134的厚度h34大于15nm或者第五电子传输层135的厚度h35大于15nm)，还能够增大第三发光器件116的正面(远离驱动背板150)光线强度，减小第三发光器件116的侧面光线强度，提高第 一发光器件112的出光率，增大第三发光器件116的亮度，降低显示面板100功耗。
图14A为根据又一些实施例的电流密度随电压的变化曲线图。图14B为根据又一些实施例的发光亮度随电压的变化曲线图。图14C为根据又一些实施例的外量子效率随电压的变化曲线图。
下面参照图14A～图14C，对本公开一些实施例中，第二发光器件114中第三电子传输层133、第四电子传输层134和第五电子传输层135在不同厚度下，第二发光器件114的电流密度、亮度和外量子效率进行举例说明。
下面参照图14A～图14C，对本公开一些实施例中，第二发光器件114中，第三电子传输层133、第四电子传输层134和第五电子传输层135在不同厚度下，第二发光器件114的电流密度、发光亮度和外量子效率进行举例说明。
需要说明的是，图14A中，横坐标为电压(单位V)，纵坐标为电流密度(单位：毫安/平方厘米，mA/cm 2)。图14B中，横坐标为电压(单位V)，纵坐标为发光亮度(单位为坎德拉每平方米cd/m 2)。图14C中，横坐标为电压(单位V)，纵坐标为外量子效率(英文全称：External Quantum Efficiency，英文简称：EQE)。可以理解地，EQE＝出射的光子数/注入的电荷数。EQE越大，发光器件110的发光性能越好。
如图14A～图14C所示，组合8～组合11为不同厚度以及材料的电子传输层130的组合。
组合8中第三电子传输层133为ZnO薄膜，厚度为10.5nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。第五电子传输层135为ZnO薄膜，厚度为10.5nm。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为8％。
组合9中第三电子传输层133为ZnO薄膜，厚度为21nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。组合9中不包含第五电子传输层135。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为8％。
组合10中第三电子传输层133为ZnMgO薄膜，厚度为9nm。第四电子传输层134为ZnO薄膜，厚度为21nm。组合10中同样不包含第五电子传输层135。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为8％。
组合11中第三电子传输层133、第四电子传输层134和第五电子传输层135的材料均为ZnO，也即是，此时至少两层电子传输层130可以视为一侧电子传输层130，厚度为30nm。
如图14A和图14B所示，当电压增大时，选用组合9、组合10和组合11 的第二发光器件114发光亮度增大，电流密度也增大，使得电流效率减小，并且，如图14C所示，选用组合9、组合10或者组合11时，第二发光器件114的EQE较小。
如图14C所示，当电压增大时，选用组合8(也即是第三电子传输层133的材料为ZnO，厚度为10.5nm。第四电子传输层134的材料为ZnMgO，厚度为9nm。第五电子传输层135的材料为ZnO，厚度为10.5nm。ZnMgO中Mg的摩尔百分比为8％)的第二发光器件114的外量子效率EQE最大，电流效率最高，提高第二发光器件114的发光性能。
也即是，如图14A～图14C所示，选用三层的电子传输层130(组合8)时，第二发光器件114的电流密度、发光亮度以及EQE，优于选用单层的电子传输层130(组合11)和选用双层电子传输层130(组合9和组合10)时，第二发光器件114的电流密度、发光亮度以及EQE。也即是，选用三层的电子传输层130时，第二发光器件114能够具有较好的发光性能。
可以理解地，由于选用三层的电子传输层130(组合8)时，第四电子传输层134的材料为ZnMgO，通过Mg离子掺杂，能够对电子起到阻挡作用，降低电子迁移率，从而减小量子点发光层126中电子的数量，提高第二发光器件114的发光效率。
此外，当第三电子传输层133的材料为ZnO，第四电子传输层134的材料为ZnMgO，第五电子传输层135的材料为ZnO时，能够在第三电子传输层133、第四电子传输层134和第五电子传输层135之间形成能级差，从而形成电子传输势垒，阻碍电子向量子点发光层126传输，平衡第二发光器件114中电子的传输能力和空穴的传输能力。
故而，在一些实施例中，当第二发光器件114包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第三电子传输层133的厚度h23为大约10.5nm，第四电子传输层134的厚度h24大约为9nm，第五电子传输层135的厚度h25为大约10.5nm。
由上述可知，如此设置，能够提高第二发光器件114的电流效率以及外量子效率，从而提高第二发光器件114的发光性能。
由上述可知，第四电子传输层134的材料包括ZnMgO。在一些示例中，第四电子传输层134中，Mg的摩尔百分比大于0，且小于或等于50％；Mg的摩尔百分比与Zn的摩尔百分比之和为1。
可以理解地，第四电子传输层134的材料包括Zn 1-XMg XO，其中，X为Mg的摩尔百分比，1-X为Zn的摩尔百分比。
可以理解地，通过调节第四电子传输层134中Mg的摩尔百分比，能够对第四电子传输层134的电子迁移率、以及第四电子传输层134的能级(例如价带顶能级VBM和导带底能级CBM)起到调节作用，从而对传输至量子点发光层126中的电子数量起到调节作用，提高第一发光器件112中电子和空穴的传输平衡性，从而提高第一发光器件112的发光效率。
在一些示例中，Mg的摩尔百分比可以大于0，且小于或等于40％。在另一些示例中，Mg的摩尔百分比可以大于0，且小于或等于30％。在又一些示例中，Mg的摩尔百分比可以大于0，且小于或等于20％。
示例的，第四电子传输层134中Mg的摩尔百分比可以为10％、20％、30％或者40％等。
可以理解地，当第四电子传输层134中，Mg的摩尔百分比大于0，且小于或等于50％时，Zn的摩尔百分比大于或等于50％，且小于100％。
在一些实施例中，第四电子传输层134中，Mg的摩尔百分比的取值范围为1％～20％。
在一些示例中，第四电子传输层134中，Mg的摩尔百分比的取值范围可以为2％～20％、5％～15％或者7％～12％等。示例的，第四电子传输层134中，Mg的摩尔百分比的取值可以为5％、8％、10％或者15％等。
可以理解地，通过调节第四电子传输层134中Mg的摩尔百分比，能够对第四电子传输层134的电子迁移率、以及第四电子传输层134的能级(例如价带顶能级VBM和导带底能级CBM)起到调节作用，从而对传输至量子点发光层126中的电子数量起到调节作用，提高第一发光器件112中电子和空穴的传输平衡性，从而提高第一发光器件112的发光效率。
可以理解地，当第四电子传输层134中，Mg的摩尔百分比的取值范围为1％～20％时，Zn的摩尔百分比的取值范围为80％～99％。
图15A为根据又一些实施例的电流密度随电压的变化曲线图。图15B为根据又一些实施例的发光亮度随电压的变化曲线图。图15C为根据又一些实施例的外量子效率随电压的变化曲线图。
下面参照图15A～图15C，对本公开一些实施例中，第二发光器件114中的第四电子传输层134中，Mg摩尔百分比不同时，第二发光器件114的电流密度、亮度和外量子效率进行举例说明。
需要说明的是，图15A中，横坐标为电压(单位V)，纵坐标为电流密度(单位：毫安/平方厘米，mA/cm 2)。图15B中，横坐标为电压(单位V)，纵坐标为发光亮度(单位为坎德拉每平方米cd/m 2)。图15C中，横坐标为 电压(单位V)，纵坐标为外量子效率(英文全称：External Quantum Efficiency，英文简称：EQE)。可以理解地，EQE＝出射的光子数/注入的电荷数。EQE越大，发光器件110的发光性能越好。
如图15A～图15C所示，组合12～组合16为第四电子传输层132中Mg的摩尔百分比不同时，不同电子传输层130的组合。
组合12中，第三电子传输层133为ZnO薄膜，厚度为10.5nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。第五电子传输层135为ZnO薄膜，厚度为10.5nm。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为8％。
组合13中，第三电子传输层133为ZnO薄膜，厚度为10.5nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。第五电子传输层135为ZnO薄膜，厚度为10.5nm。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为6.5％。
组合14中，第三电子传输层133为ZnO薄膜，厚度为10.5nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。第五电子传输层135为ZnO薄膜，厚度为10.5nm。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为5％。
组合15中，第三电子传输层133为ZnO薄膜，厚度为10.5nm。第四电子传输层134为ZnMgO薄膜，厚度为9nm。第五电子传输层135为ZnO薄膜，厚度为10.5nm。其中，第四电子传输层134中，ZnMgO中Mg的摩尔百分比为2.5％。
组合16中第三电子传输层133、第四电子传输层134和第五电子传输层135的材料均为ZnO，也即是，此时至少两层电子传输层130可以视为一侧电子传输层130，厚度为30nm。
如图15A～图15C所示，第二发光器件114选用三层的电子传输层130(包括第三电子传输层133、第四电子传输层134和第五电子传输层135，例如(组合12、组合13、组合14和组合15)时，电流密度、发光亮度以及EQE均优于选用单层的电子传输层130(组合16)，也即是，选用三层的电子传输层130时，第二发光器件114能够具有较好的发光性能。
可以理解地，由于选用三层的电子传输层130时(组合12、组合13、组合14和组合15)，第四电子传输层134的材料为ZnMgO，通过Mg离子掺杂，能够降低电子迁移率，从而减小量子点发光层126中电子的数量，提高第二发光器件114的发光效率。
此外，当第三电子传输层133的材料为ZnO，第四电子传输层134的材料为ZnMgO，第五电子传输层135的材料为ZnO时，能够在第三电子传输层133的材料为ZnO，第四电子传输层134的材料为ZnMgO，第五电子传输层135的材料为ZnO之间形成能级差，从而形成电子传输势垒，阻碍电子向量子点发光层126传输，平衡第二发光器件114中电子的传输能力和空穴的传输能力。
如图15A和图15B所示，当电压增大时，选用组合12的第二发光器件114的外量子效率EQE最大，电流效率最高，提高第二发光器件114的发光性能。
而组合13、组合14和组合15中，当电压增大时，电流密度和发光亮度均增大，影响了第二发光器件114的外量子效率EQE和电流效率。
故而，在一些实施例中，当第二发光器件114包括第三电子传输层133、第四电子传输层134和第五电子传输层135时，第四电子传输层134中，Mg的摩尔百分比大约为8％。
由上述可知，如此设置，能够提高第二发光器件114的电流效率以及外量子效率，从而提高第二发光器件114的发光性能。
在一些示例中，当第三电子传输层133为ZnO薄膜，厚度为10.5nm，第四电子传输层134的为ZnMgO薄膜，厚度为9nm，其中，ZnMgO中Mg的摩尔百分比为8％，第五电子传输层135为ZnO薄膜，厚度为10.5nm时，第三电子传输层133、第四电子传输层134和第五电子传输层135的能级关系如图12A所示。
在一些示例中，ZnO薄膜、ZnMgO薄膜(其中Mg的摩尔百分比为5％)和ZnMgO薄膜(其中Mg的摩尔百分比为8％)的导带底能级CBM和价带顶能级VBM的取值如表1所示。
表1
  VBM(eV) CBM(eV)
ZnO -7.3 -4.1
ZnMg(5％)O -7.4 -4.0
ZnMg(8％)O -7.4 -3.6
可以理解地，通过设置电子传输层130为不同的n型氧化物薄膜，并且调节n型氧化物薄膜中，元素的摩尔百分比，能够对电子传输层130的能级起到调节作用，使得至少两层电子传输层130之间形成电子势垒，阻碍电子向量子点发光层126传输，提高电子迁移率和空穴迁移率的一致性，从而提 高发光器件110的发光效率。
图16为根据一些实施了的发光器件的制备方法步骤流程图。
另一方面，本公开的实施例提供了一种显示面板的制备方法。可以理解地，本公开的实施例提供的显示面板的制备方法，用于制备如上述的显示面板100，因此具有上述的全部有益效果，在此不再赘述。
在一些实施例中，显示面板的制备方法包括形成多个发光器件。其中，如图16所示，形成一个发光器件的步骤包括：
步骤S101，形成第二电极。
步骤S102，采用磁控溅射工艺，在第二电极的一侧形成至少两层电子传输层。至少两层电子传输层中至少一层电子传输层的材料包括氧化物。
可以理解地，采用磁控溅射的方式形成至少两层电子传输层130，一方面，能够减小形成的电子传输层130中，氧化物(例如ZnO)的表面态，从而减小电子传输层130中氧化物与量子点发光层126之间相互作用，有利于降低界面缺陷引起的非辐射复合(例如俄歇复合)损失，提高发光器件110的发光效率。
另一方面，能够减小在后形成的电子传输层130，对在先形成的电子传输层130造成的影响，不易破坏在先形成的电子传输层130，从而能够灵活控制至少两层电子传输层130的厚度以及材料等，从而能够灵活控制第一发光器件112的光学特性以及电学特性，提高第一发光器件112中电子迁移率和空穴迁移率的一致性，均衡第一发光器件112中电子和空穴的传输能力，从而提高量子点发光层126中电子数量和空穴数量的一致性，提高第一发光器件112的发光效率。
再一方面，采用磁控溅射工艺形成的ZnO薄膜中，ZnO不会或者仅仅少会量呈纳米颗粒状，从而，能够降低ZnO薄膜的表面粗糙度。
又一方面，采用磁控溅射工艺形成至少两层电子传输层130，还能够匹配高分辨率显示，并且工艺简单，能够与驱动背板150的制备工艺适配，提高显示面板100的显示性能，降低显示面板100的生产成本。
并且，至少两层电子传输层130中至少一层电子传输层的材料包括氧化物，使得电子能够穿过电子传输层，迁移到量子点发光层126之内。
在一些示例中，任一层电子传输层130的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，且任意相邻的两层电子传输层130的材料不同。
可以理解地，在形成至少两层电子传输层130之后，可以通过飞行时间 二次离子质谱仪(英文全称：Time Of Flight Secondary Ion Mass Spectrometry，英文简称：TOF-SIMS)测量不同的电子传输层130中，各个元素的纵向深度以及分布强度，以得到每层电子传输层130的材料和厚度等。
步骤S103，在至少两层电子传输层远离第二电极的一侧形成量子点发光层。
在一些示例中，在形成至少两层电子传输层130之后，可以采用旋涂量子点溶液、刮涂量子点溶液或者喷墨打印量子点溶液等方式，在至少两层电子传输层130远离第二电极124的一侧涂覆量子点溶液。而后在加热平台或者烘箱中烘烤，烘烤的温度范围为80℃～150℃，烘烤时间为5分钟～30分钟。示例的，可以控制加热平台的温度为120℃，烘烤10分钟，以在至少两层电子传输层130远离第二电极124的一侧形成量子点发光层126。
步骤S104，在量子点发光层远离至少两层电子传输层的一侧形成第一电极。
在一些示例中，可以采用蒸镀的方式，在量子点发光层126远离至少两层电子传输层130的一侧形成第一电极122。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应以所述权利要求的保护范围为准。

Claims (30)

  1. 一种显示面板，包括多个发光器件；任一个发光器件包括：
    第一电极和第二电极；
    量子点发光层，位于所述第一电极和所述第二电极之间；以及，
    至少两层电子传输层，所述至少两层电子传输层层叠设置，且位于所述第二电极和所述量子点发光层之间；
    其中，所述多个发光器件包括第一发光器件和第二发光器件，所述第一发光器件用于发射第一颜色光，所述第二发光器件用于发射第二颜色光，所述第一颜色光的波长大于所述第二颜色光的波长；
    所述第一发光器件中电子传输层的数量，小于所述第二发光器件中电子传输层的数量。
  2. 根据权利要求1所述的显示面板，其中，所述第一发光器件中的至少两层电子传输层的厚度之和，大于所述第二发光器件中的至少两层电子传输层的厚度之和。
  3. 根据权利要求2所述的显示面板，还包括驱动背板，所述多个发光器件位于所述驱动背板的一侧；所述第二电极相对于所述第一电极靠近所述驱动背板；
    所述第一发光器件包括第一部分第一电极，所述第二发光器件包括第二部分第一电极；所述第一部分第一电极远离所述驱动背板一侧的表面与所述驱动背板之间的距离，大于所述第二部分第一电极远离所述驱动背板一侧的表面与所述驱动背板之间的距离。
  4. 根据权利要求1～3中任一项所述的显示面板，其中，所述第一发光器件中的所述至少两层电子传输层包括：
    第一电子传输层和第二电子传输层，所述第二电子传输层的电子迁移率小于所述第一电子传输层的电子迁移率。
  5. 根据权利要求4所述的显示面板，其中，所述第一电子传输层相对于所述第二电子传输层靠近所述第二电极；且所述第一电子传输层的导带底能级，小于所述第二电子传输层的导带底能级。
  6. 根据权利要求4或5所述的显示面板，其中，所述第一电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，所述第二电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，且所述第一电子传输层的材料和所述第二电子传输层的材料不同。
  7. 根据权利要求6所述的显示面板，其中，所述第二电子传输层的材料 包括ZnMgO；所述第二电子传输层中，Mg的摩尔百分比大于0，且小于或等于50％；Mg的摩尔百分比与Zn的摩尔百分比之和为1。
  8. 根据权利要求7所述的显示面板，其中，所述第二电子传输层中，Mg的摩尔百分比的取值范围为1％～20％。
  9. 根据权利要求8所述的显示面板，其中，所述第二电子传输层中，Mg的摩尔百分比大约为5％。
  10. 根据权利要求4～9中任一项所述的显示面板，其中，所述第一电子传输层的厚度大于0nm，且小于或等于60nm；和/或，
    所述第二电子传输层的厚度大于0nm，且小于或等于60nm；
    所述第一电子传输层的厚度大于所述第二电子传输层的厚度。
  11. 根据权利要求10所述的显示面板，其中，
    所述第一电子传输层的厚度的取值范围为30nm～50nm；和/或，
    所述第二电子传输层的厚度的取值范围为1nm～30nm。
  12. 根据权利要求11所述的显示面板，其中，
    所述第一电子传输层的厚度大约为45nm；和/或，
    所述第二电子传输层的厚度大约为15nm。
  13. 根据权利要求1～12中任一项所述的显示面板，还包括第三发光器件；所述第三发光器件用于发射第三颜色光；所述第二颜色光的波长，大于所述第三颜色光的波长；
    所述第一发光器件中电子传输层的数量，小于所述第三发光器件中电子传输层的数量。
  14. 根据权利要求13所述的显示面板，其中，所述第二发光器件和所述第三发光器件中，至少一个发光器件的至少两层电子传输层包括：
    第三电子传输层、第四电子传输层和第五电子传输层；所述第四电子传输层的电子迁移率，小于所述第三电子传输层的电子迁移率；且所述第四电子传输层的电子迁移率，小于所述第五电子传输层的电子迁移率。
  15. 根据权利要求14所述的显示面板，其中，所述第三电子传输层、所述第四电子传输层和所述第五电子传输层沿所述第二电极至所述量子点发光层的方向，依次远离所述第二电极；
    其中，所述第三电子传输层的导带底能级，小于所述第四电子传输层的导带底能级；或，所述第四电子传输层的导带底能级，小于所述第五电子传输层的导带底能级。
  16. 根据权利要求15所述的显示面板，其中，所述第三电子传输层的导 带底能级，与所述第五电子传输层的导带底能级相等。
  17. 根据权利要求14～16中任一项所述的显示面板，其中，所述第三电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，所述第四电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，所述第五电子传输层的材料包括ZnO、GZO、AZO、IZO、IGZO和ZnMgO中的任一个，且所述第四电子传输层的材料与所述第三电子传输层的材料不同；和/或，
    所述第四电子传输层的材料与所述第五电子传输层的材料不同。
  18. 根据权利要求17所述的显示面板，其中，所述第四电子传输层的材料包括ZnMgO，且所述第四电子传输层中，Mg的摩尔百分比大于0，且小于或等于50％；Mg的摩尔百分比与Zn的摩尔百分比之和为1。
  19. 根据权利要求18所述的显示面板，其中，所述第四电子传输层中，Mg的摩尔百分比的取值范围为1％～20％。
  20. 根据权利要求19所述的显示面板，其中，当所述第二发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第四电子传输层中，Mg的摩尔百分比大约为8％。
  21. 根据权利要求14～20中任一项所述的显示面板，其中，当所述第二发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第三电子传输层的厚度大于0nm，且小于或等于40nm；所述第四电子传输层的厚度大于0nm，且小于或等于30nm；所述第五电子传输层的厚度大于0nm，且小于或等于40nm；
    当所述第三发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第三电子传输层的厚度大于0nm，且小于或等于30nm；所述第四电子传输层的厚度大于0nm，且小于或等于20nm；所述第五电子传输层的厚度大于0nm，且小于或等于30nm。
  22. 根据权利要求21所述的显示面板，其中，当所述第二发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第三电子传输层的厚度的取值范围为5nm～20nm，所述第四电子传输层的厚度的取值范围为1nm～15nm，所述第五电子传输层的厚度的取值范围为5nm～20nm；
    当所述第三发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第三电子传输层的厚度的取值范围为5nm～15nm，所述第四电子传输层的厚度的取值范围为1nm～15nm，所述第五 电子传输层的厚度的取值范围为5nm～15nm。
  23. 根据权利要求22所述的显示面板，其中，当所述第二发光器件包括所述第三电子传输层、所述第四电子传输层和所述第五电子传输层时，所述第三电子传输层的厚度为大约10.5nm，所述第四电子传输层的厚度大约为9nm，所述第五电子传输层的厚度为大约10.5nm。
  24. 根据权利要求13～23中任一项所述的显示面板，其中，所述第一颜色光为红光，所述第二颜色光为绿光，所述第三颜色光为蓝光。
  25. 根据权利要求1～9、13～20中任一项所述的显示面板，其中，所述至少两层电子传输层的厚度之和的取值范围为5nm～150nm。
  26. 根据权利要求25所述的显示面板，其中，所述至少两层电子传输层的厚度之和的取值范围为20nm～70nm。
  27. 根据权利要求26所述的显示面板，其中，所述至少两层电子传输层的厚度之和的取值范围为20nm～60nm。
  28. 根据权利要求1～27中任一项所述显示面板，还包括：
    电子注入层，位于所述第二电极和所述至少两层电子传输层之间；
    空穴注入层，位于所述第一电极和所述量子点发光层之间；
    空穴传输层，位于所述空穴注入层和所述量子点发光层之间；
    光耦合层，位于所述第一电极远离所述空穴注入层的一侧。
  29. 一种显示面板的制备方法，包括形成多个发光器件；其中，形成一个发光器件的步骤包括：
    形成第二电极；
    采用磁控溅射工艺，在第二电极的一侧形成至少两层电子传输层；所述至少两层电子传输层中至少一层电子传输层的材料包括氧化物；
    在所述至少两层电子传输层远离所述第二电极的一侧形成量子点发光层；
    在所述量子点发光层远离所述至少两层电子传输层的一侧形成第一电极。
  30. 一种显示装置，包括如权利要求1～29中任一项所述显示面板。
PCT/CN2022/103026 2022-06-30 2022-06-30 显示面板、显示面板的制备方法和显示装置 WO2024000483A1 (zh)

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