WO2024040464A1 - 一种显示基板、其制作方法及显示装置 - Google Patents

一种显示基板、其制作方法及显示装置 Download PDF

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Publication number
WO2024040464A1
WO2024040464A1 PCT/CN2022/114498 CN2022114498W WO2024040464A1 WO 2024040464 A1 WO2024040464 A1 WO 2024040464A1 CN 2022114498 W CN2022114498 W CN 2022114498W WO 2024040464 A1 WO2024040464 A1 WO 2024040464A1
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emitting
quantum dot
layer
dot light
display substrate
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PCT/CN2022/114498
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English (en)
French (fr)
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李东
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北京京东方技术开发有限公司
京东方科技集团股份有限公司
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Priority to PCT/CN2022/114498 priority Critical patent/WO2024040464A1/zh
Priority to CN202280002815.6A priority patent/CN117941485A/zh
Publication of WO2024040464A1 publication Critical patent/WO2024040464A1/zh

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00

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  • the present disclosure relates to the field of display technology, and in particular to a display substrate, a manufacturing method thereof, and a display device.
  • Quantum Dot as a new type of luminescent material, has the advantages of high light color purity, high luminescence quantum efficiency, adjustable luminescence color, and long service life. It has become the current research topic of luminescent materials in new light-emitting diodes. Hotspot. Therefore, Quantum Dot Light Emitting Diodes (QLED) using quantum dot materials as the light-emitting layer have become the main direction of current research on new display devices.
  • QLED Quantum Dot Light Emitting Diodes
  • Embodiments of the present disclosure provide a display substrate, a manufacturing method thereof, and a display device.
  • the specific solutions are as follows:
  • a display substrate provided by an embodiment of the present disclosure includes a plurality of top-emitting quantum dot light-emitting devices.
  • Each of the top-emitting quantum dot light-emitting devices includes: a first electrode and a second electrode arranged oppositely, and the first electrode is located on the first electrode. and the quantum dot light-emitting layer between the second electrode, and the electron transport layer between the first electrode and the quantum dot light-emitting layer; wherein,
  • the electron transport layer has a metal reflective layer inside.
  • the ratio of the area of the metal reflective layer to the area of the electron transport layer in each top-emitting quantum dot light emitter is 50% to 100 %.
  • the angle between the plane where the metal reflective layer is located and the plane where the electron transmission layer is located is less than 1 ⁇ degree.
  • the plurality of top-emitting quantum dot light-emitting devices include a plurality of top-emitting quantum dot light-emitting devices with different emission wavelengths, and each of the top-emitting quantum dot light-emitting devices has The distance between the metal reflective layer and the first electrode has an inverse correlation trend with the emission wavelength of the top-emitting quantum dot light-emitting device.
  • the plurality of top-emitting quantum dot light-emitting devices with different emission wavelengths include red top-emitting quantum dot light-emitting devices, green top-emitting quantum dot light-emitting devices and blue top-emitting quantum dot light-emitting devices.
  • the distance between the metal reflective layer in the red top-emitting quantum dot light-emitting device and the first electrode is a first distance
  • the metal reflective layer in the green top-emitting quantum dot light-emitting device is The distance between the first electrodes is a second distance
  • the distance between the metal reflective layer in the blue top-emitting quantum dot light-emitting device and the first electrode is a third distance; wherein, the first The distance is 0 ⁇ 20nm
  • the second distance is 20nm ⁇ 40nm
  • the third distance is 40nm ⁇ 60nm.
  • the metal reflective layer has a planar structure.
  • the area of the metal reflection layer is smaller than the area of the electron transmission layer, and the metal reflection layer is located in the central area of the electron transmission layer.
  • the metal reflective layer includes a plurality of independently arranged hollow structures.
  • the plurality of hollow structures are distributed in an array.
  • the above display substrate provided by the embodiment of the present disclosure also includes a plurality of data lines extending along the first direction and arranged along the second direction, and the plurality of hollow structures are extending along the second direction and A plurality of strip-shaped hollow structures are arranged along the first direction, and the first direction and the second direction are arranged crosswise.
  • the distance between adjacent hollow structures in each top-emitting quantum dot light-emitting device is equal to the luminescence wavelength of the top-emitting quantum dot light-emitting device.
  • the metal reflective layer includes a plurality of independently arranged reflective parts and a hollow structure located between adjacent reflective parts.
  • the plurality of reflective parts are distributed in an array.
  • the above display substrate provided by the embodiment of the present disclosure further includes a plurality of data lines extending along the first direction and arranged along the second direction, and the plurality of reflective portions extend along the second direction and A plurality of strip-shaped reflective parts are arranged along the first direction, and the first direction and the second direction are intersectingly arranged.
  • the distance between adjacent reflective portions in each top-emitting quantum dot light-emitting device is equal to the luminescence wavelength of the top-emitting quantum dot light-emitting device.
  • the reflectivity of the metal reflective layer in the visible light range is 30% to 60%.
  • the work function of the metal reflective layer is 2.2eV ⁇ 4.2eV, and the thickness of the metal reflective layer is 3nm ⁇ 5nm.
  • the material of the metal reflective layer includes Mg, Ag, and Al.
  • the material of the electron transport layer includes metal oxide nanoparticles, and the surface of the metal reflective layer facing away from the first electrode is uneven.
  • the oxygen vacancy ratio of the surface of the electron transport layer in contact with the first electrode is smaller than the oxygen vacancy ratio of the surface of the electron transport layer in contact with the metal reflective layer. Oxygen vacancy ratio.
  • the thickness of the electron transport layer is 50 nm to 80 nm.
  • the above display substrate provided by the embodiment of the present disclosure further includes: a hole transport layer located between the quantum dot light-emitting layer and the second electrode, and a hole transport layer located between the hole transport layer and the second electrode. a hole injection layer between the second electrodes.
  • the thickness of the hole transport layer is 10 nm to 40 nm
  • the thickness of the hole injection layer is 3 nm to 7 nm
  • the thickness of the quantum dot light emitting layer is It is 10nm ⁇ 40nm.
  • an embodiment of the present disclosure also provides a display device, including any of the above display substrates provided by the embodiment of the present disclosure.
  • an embodiment of the present disclosure also provides a manufacturing method for manufacturing any of the above-mentioned display substrates provided by an embodiment of the present disclosure, including:
  • each top-emitting quantum dot light-emitting device includes: a first electrode and a second electrode arranged oppositely, and a first electrode and a second electrode located between the first electrode and the second electrode.
  • the electron transmission layer and the metal reflective layer are manufactured, specifically:
  • a second electron transport layer is formed on the metal reflective layer; the second electron transport layer and the first electron transport layer constitute the electron transport layer.
  • Figure 1 is a schematic structural diagram of a top-emitting quantum dot light-emitting device in the related art
  • Figure 2 is a schematic diagram of the simulation of the light emission angle distribution when the electron transport layer in the red quantum dot light-emitting device corresponding to Figure 1 has different thicknesses;
  • Figure 3 is a schematic diagram of the simulation of the light emission angle distribution when the electron transport layer in the green quantum dot light-emitting device corresponding to Figure 1 has different thicknesses;
  • Figure 4 is a schematic diagram of the simulation of light emission angle distribution when the electron transport layer in the blue quantum dot light-emitting device corresponding to Figure 1 has different thicknesses;
  • Figure 5 is a schematic diagram of current efficiency-voltage corresponding to different thicknesses of the electron transport layer in the green quantum dot light-emitting device corresponding to Figure 1;
  • Figure 6 is a schematic structural diagram of a top-emission quantum dot light-emitting device provided by an embodiment of the present disclosure
  • Figure 7A is a schematic structural diagram of a red top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure
  • Figure 7B is a schematic structural diagram of a green top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure
  • Figure 7C is a schematic structural diagram of a blue top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 8 is a schematic structural diagram of yet another top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 9 is a schematic plan view of the metal reflective layer in Figure 6;
  • Figure 10 is a schematic structural diagram of yet another top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 11 is a schematic structural diagram of yet another top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 12A is a schematic structural diagram of another red top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 12B is a schematic structural diagram of another green top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figure 12C is a schematic structural diagram of another blue top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure.
  • Figures 13A to 13D are respectively several plan views of the metal reflective layer in Figure 11;
  • Figures 14A to 14D are other plan views of the metal reflective layer in Figure 11;
  • Figure 15 is a schematic structural diagram of an inverted top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure
  • Figure 16 is a schematic structural diagram of a positive top-emitting quantum dot light-emitting device provided by an embodiment of the present disclosure
  • 17A-17H are respectively schematic structural diagrams of a display substrate manufacturing method after each manufacturing step is performed according to an embodiment of the present disclosure.
  • AQLED active electroluminescent quantum dot light-emitting display products
  • the most research on QLED is the bottom-emitting structure.
  • the demand for high resolution in high-resolution display products requires QLED devices to adopt a top-emitting structure.
  • the top-emitting structure can increase the aperture ratio.
  • the requirements for the cavity length are obviously different.
  • the red QLED device has the longest cavity length, about 140nm
  • the blue QLED device has the smallest cavity length, about 75nm.
  • red QLED devices due to the large cavity length, there is a large adjustment space within the appropriate cavity length range to optimize the electrical structure, and the film thickness of each layer can also be larger, so it is easier to achieve electrical balance.
  • the film thickness of each layer within the suitable cavity length range is small, and there is less space to adjust the electrical balance.
  • the blue QLED device has a small cavity length and the film thickness of each layer is small, it will also bring The problem of device leakage further affects the electrical balance.
  • Figure 1 is a schematic structural diagram of a top-emitting QLED device in the related art, including: a first electrode 1 and a second electrode 2 arranged oppositely, located between the first electrode 1 and the second electrode 2
  • the quantum dot light-emitting layer 3 located between the first electrode 1 and the quantum dot light-emitting layer 3, the hole injection layer 5 located between the second electrode 2 and the quantum dot light-emitting layer 3, and the quantum dot Hole transport layer 6 between light emitting layer 3 and hole injection layer 5.
  • the inventor of this case found through research that when the thickness of the quantum dot light-emitting layer 3 is 30nm, the thickness of the hole transport layer 6 is 40nm, and the thickness of the hole injection layer 5 is 7nm, the electrical balance of the QLED device is better.
  • the thickness of the quantum dot light-emitting layer 3 is 30nm
  • the thickness of the hole transport layer 6 is 40nm
  • the thickness of the hole injection layer 5 is 7nm.
  • Different thicknesses of the electron transport layer 4 are used for red, green and blue QLED devices respectively. Simulate the impact on light extraction efficiency, as shown in Figures 2-4.
  • Figure 2 shows that the QLED device corresponding to Figure 1 is a red QLED device, and the electron transport layer 4 has different thicknesses (20nm, 40nm, 60nm, 70nm, 80nm) The corresponding simulation diagram of the light emission angle distribution is shown at this time. At this time, the cavity lengths corresponding to the electron transport layer 4 with different thicknesses are approximately 100nm, 120nm, 140nm, 150nm, and 160nm respectively. It can be seen from Figure 2 that the optimal light extraction efficiency is when the thickness of the electron transport layer 4 is 60nm (that is, the cavity length is 140nm).
  • Figure 3 is a simulation diagram of the light emission angle distribution when the QLED device corresponding to Figure 1 is a green QLED device and the electron transport layer 4 has different thicknesses (20nm, 30nm, 40nm, 50nm, 60nm). At this time, the electron transport layer 4 has different thicknesses.
  • the corresponding cavity lengths are approximately 100nm, 110nm, 120nm, 130nm, and 140nm respectively. It can be seen from Figure 3 that the optimal light extraction efficiency is when the thickness of the electron transport layer 4 is 40nm (that is, the cavity length is 120nm).
  • Figure 4 is a schematic diagram of the corresponding light emission angle distribution simulation diagram when the QLED device corresponding to Figure 1 is a blue QLED device and the electron transport layer 4 has different thicknesses (10nm, 20nm, 30nm, 40nm, 50nm). At this time, the electron transport layer has different thicknesses. 4The corresponding cavity lengths are approximately 90nm, 100nm, 110nm, 120nm, and 130nm respectively. It can be seen from Figure 4 that the optimal light extraction efficiency is when the thickness of the electron transport layer 4 is 20nm (that is, the cavity length is 100nm). Therefore, the best light extraction efficiency is achieved when the thickness of the electron transport layer 4 of the red, green and blue QLED devices is 60nm, 40nm and 20nm respectively.
  • the device current efficiency is the worst. Therefore, when the optical performance of the device is optimal, the electrical performance of the device is not. The worst, the main reason is that when the thickness of the electron transport layer 4 is 40nm, the thickness is low at this time, too many electrons are injected, and the electrical balance of the device is the worst, which in turn affects the overall performance of the device.
  • the light extraction efficiency is optimal when the thickness of the electron transport layer 4 of the blue QLED device is 20 nm.
  • the thickness of the electron transport layer 4 is thin at this time, resulting in greater leakage of the device and further increasing the electrical impact on the device. Therefore, how to find a suitable device structure and unify the optimal electrical and optical structures of the device is an urgent technical problem that those skilled in the art need to solve.
  • inventions of the present disclosure provide a display substrate including a plurality of top-emitting quantum dot light-emitting devices, as shown in Figure 6.
  • Figure 6 only illustrates the structure of one of the top-emitting quantum dot light-emitting devices.
  • the quantum dot emitting light-emitting device includes: a first electrode 1 and a second electrode 2 arranged oppositely, a quantum dot light-emitting layer 3 located between the first electrode 1 and the second electrode 2, and a quantum dot light-emitting layer located between the first electrode 1 and the quantum dot light-emitting layer.
  • electron transport layer 4 between 3; where,
  • the electron transport layer 4 has a metal reflective layer 7 inside.
  • a metal reflective layer is provided inside the electron transmission layer.
  • the metal reflective layer can adjust the microcavity length of the device. For example, while ensuring the electrical balance of the device, the current efficiency (electronics) is increased.
  • the transmission layer is thicker
  • the corresponding microcavity length (not suitable for light extraction) is adjusted to a more appropriate microcavity length (reducing the microcavity length, which facilitates light extraction), and passes through the microcavity between the metal reflective layer and the second electrode.
  • the thickness of the electron transport layer between the metal reflective layer and the quantum dot light-emitting layer can be lowered to achieve optimal light extraction efficiency.
  • an electron transport layer between the metal reflective layer and the first electrode.
  • This part of the electron transport layer can be used to adjust the electrical balance of the device so that the thickness of the electron transport layer in the device is not too low and the device can achieve electrical balance. Therefore, embodiments of the present disclosure can achieve optimal light extraction efficiency and optimal current efficiency of the device at the same time.
  • the area of the metal reflective layer in each top-emitting quantum dot light emitter is equal to
  • the area ratio of the electron transport layer may be 50% to 100%.
  • the ratio of the area of the metal reflective layer to the area of the electron transport layer may be 50%, 60%, 70%, 80%, 90%, 100%, etc.
  • the plane of the metal reflective layer and the plane of the electron transmission layer are generally designed to be parallel.
  • the metal reflection The plane of the layer and the plane of the electron transmission layer may not be completely parallel.
  • the angle between the plane of the metal reflective layer and the plane of the electron transmission layer is less than 1 ⁇ degree.
  • multiple top-emitting quantum dot light-emitting devices include multiple top-emitting quantum dot light-emitting devices with different emission wavelengths (for example, FIG. 7A corresponds to one luminescence wavelength, Figure 7B corresponds to another luminescence wavelength, and Figure 7C corresponds to yet another luminescence wavelength).
  • the distance between the metal reflective layer 7 and the first electrode 1 in each top-emitting quantum dot light-emitting device has an inverse correlation trend with the emission wavelength of the top-emitting quantum dot light-emitting device, for example, Figure 7A
  • the top-emitting quantum dot light-emitting device shown in Figure 7B has the largest luminescence wavelength
  • the top-emission quantum dot light-emitting device shown in Figure 7B has the second largest luminescence wavelength
  • the top-emission quantum dot light-emitting device shown in Figure 7C has the smallest luminescence wavelength
  • the distance between the metal reflective layer 7 and the first electrode 1 in the top-emitting quantum dot light-emitting device shown in FIG. The distance is second, and the distance between the metal reflective layer 7 and the first electrode 1 in the top-emitting quantum dot light-emitting device shown in Figure 7C is the largest, so that devices with different emission wavelengths can ensure optimal light extraction efficiency.
  • multiple top-emitting quantum dot light-emitting devices with different emission wavelengths may include red top-emitting quantum dot light-emitting devices (Figure 7A shown), a green top-emitting quantum dot light-emitting device (shown in Figure 7B) and a blue top-emitting quantum dot light-emitting device (shown in Figure 7C), the metal reflective layer 7 and the first electrode in the red top-emitting quantum dot light-emitting device
  • the distance between 1 is the first distance D1
  • the distance between the metal reflective layer 7 in the green top-emitting quantum dot light-emitting device and the first electrode 1 is the second distance D2
  • the metal in the blue top-emitting quantum dot light-emitting device is
  • the distance between the reflective layer 7 and the first electrode 1 is the third distance D3, the first distance D1 is smaller than the second distance D2, and the second distance D2 is smaller than
  • the microcavity length corresponding to the devices with different luminescent colors is the corresponding microcavity length when the light extraction efficiency is optimal; since it can be adjusted
  • the position of the metal reflective layer 7 in the electron transport layer 4 adjusts the length of the microcavity. Therefore, the thickness of the electron transport layer 4 can be set to a corresponding thickness range when the current efficiency is better, so that the device does not suffer from leakage problems.
  • the first distance D1 may be 0-20 nm, and the distance between the metal reflective layer 7 and the quantum dot light-emitting layer 3 is about 60 nm.
  • the second distance D2 can be 20nm ⁇ 40nm, and the distance between the metal reflective layer 7 and the quantum dot light-emitting layer 3 is about 40nm
  • the third distance D3 can be 40nm ⁇ 60nm , the distance between the metal reflective layer 7 and the quantum dot light-emitting layer 3 is about 20nm.
  • the range setting of the first distance D1, the second distance D2 and the third distance D3 can make the electrical performance and optical performance of the device better.
  • the reflectivity of the metal reflective layer in the visible light range can be in the range of 30% to 60%, that is, the metal reflective layer has a certain transmittance and a certain Reflectivity, the length of the microcavity of the device can be adjusted.
  • the work function of the metal reflective layer may be 2.2eV ⁇ 4.2eV, and the thickness of the metal reflective layer may be 3nm ⁇ 5nm. The metal reflective layer within this thickness range will not affect the electrical performance of the device.
  • the material of the metal reflective layer may include but is not limited to metals such as Mg, Ag, and Al.
  • the material of the electron transport layer may include metal oxide nanoparticles, such as ZnO or ZnMgO, etc.
  • the electron transport layer 4 is generally prepared by sputtering or evaporation.
  • the metal reflective layer 7 can use the same manufacturing process as the electron transport layer 4, for example, both use sputtering. When the electron transport layer is sputtered, just add a step of metal sputtering, no need.
  • FIG. 8 of the embodiment of the present disclosure is only for schematically illustrating that the surfaces of the electron transport layer 4 and the metal reflective layer 7 have an uneven structure, and does not represent the actual uneven surface structure.
  • the metal atoms (represented by M) on the surface of the metal reflective layer 7 that are in contact with the electron transport layer 4 may be different from those in the electron transport layer 4 .
  • Chemical bonds are formed between O atoms, for example, M-O bonds are formed.
  • the M-O bonds formed on the surface will not cause the overall film layer of the metal reflective layer 7 to form oxides.
  • the interior of the metal reflective layer 7 is still made of metal and is reflective; and, the formed The M-O bond can increase the oxygen vacancy ratio in the electron transport layer 4, that is, the oxygen vacancy ratio on the surface of the electron transport layer 4 in contact with the first electrode 1 is smaller than the oxygen vacancy ratio on the surface of the electron transport layer 4 in contact with the metal reflective layer 7, so that The electron conductivity of the electron transport layer 4 can be reduced, thereby reducing the electron injection efficiency in the device and improving the carrier injection balance.
  • FIG. 9 is a schematic plan view of the metal reflective layer 7 in FIG. 6 , and the metal reflective layer 7 has a planar structure. Specifically, the area of the metal reflective layer 7 may be equal to the area of the electron transport layer 4.
  • FIG. 10 is another schematic cross-sectional view of the top-emitting light-emitting device provided by the embodiment of the present disclosure, in which the metal reflective layer 7 is a surface. structure, the area of the metal reflective layer 7 can be smaller than the area of the electron transmission layer 4, and the metal reflective layer 7 is located in the central area of the electron transmission layer 4, so that the electron transmission layer 4 in the edge area has an integrated structure, which can ensure that the electron transmission layer 4 Continuity improves the electrical performance; and the metal reflective layer 7 shortens the cavity length, which can make the viewing angle more focused on the front light emission and reduce the side light emission.
  • the design position of the metal reflective layer 7 in devices with different emission wavelengths refer to the design position method shown in FIG. 6 .
  • FIG. 11 is another top-emission light-emitting device provided by the embodiment of the present disclosure.
  • a cross-sectional schematic diagram, Figures 12A to 12C are respectively a cross-sectional schematic diagram of the quantum dot light-emitting layer in the structure corresponding to Figure 11 when it is a red quantum dot light-emitting layer, a green quantum dot light-emitting layer, and a blue quantum dot light-emitting layer, Figures 13A to 13D
  • Figures 13A to 13D These are several schematic plan views of the metal reflective layer 7 in FIG. 11 .
  • the metal reflective layer 7 includes a plurality of independently arranged hollow structures 71 . Specifically, the metal reflective layer 7 with the hollow structure 71 retains its light reflection effect, and the hollow structure 71 can ensure the continuity of the electron transmission layer 4 and improve the electrical performance. In addition, in the same light-emitting device, since the metal reflective layer 7 has a hollow structure 71, the distance between the reflective part of the metal reflective layer 7 (the part between adjacent hollow structures 71) and the second electrode 2 can be regarded as A microcavity length. The length of the microcavity in the area where the hollow structure 71 is located is the distance between the electron transport layer 4 and the second electrode 2. That is, the area where the hollow structure 71 is located and the reflective part of the metal reflective layer 7 will form two thicknesses.
  • Microcavity length but the inventor of this case found that the length difference between the above two microcavities in the same light-emitting device is within 5nm, and the difference in microcavity length contributes to the shift of the luminescence peak position in the PL spectrum of the light-emitting device by less than 1nm. . Therefore, although the metal reflective layer 7 changes the spectrum of the emitted light, the change in the color purity of the device is within an acceptable range.
  • multiple hollow structures 71 can be distributed in an array, which can make the length of the microcavity of the device uniform and improve the color of the device. purity; and the production process can also be unified.
  • the shape of the hollow structure 71 may be square; as shown in FIG. 13B, the shape of the hollow structure 71 may be circular; as shown in FIG. As shown in 13C, the shape of the hollow structure 71 may be triangular; of course, it is not limited to this.
  • the above-mentioned display substrate provided by the embodiment of the present disclosure also includes a plurality of data lines extending along the first direction and arranged along the second direction.
  • the plurality of hollow structures 71 may be formed along the first direction.
  • a plurality of strip-shaped hollow structures extend in the second direction Y and are arranged along the first direction X.
  • the first direction It can improve the light extraction efficiency of the device.
  • the distance between adjacent hollow structures in each top-emitting quantum dot light-emitting device has a positive correlation trend with the emission wavelength of the top-emitting quantum dot light-emitting device. For example, the distance between adjacent hollow structures in red top-emitting quantum dot light-emitting devices is the largest, followed by the distance between adjacent hollow structures in green top-emitting quantum dot light-emitting devices, and the distance between adjacent hollow structures in blue top-emitting quantum dot light-emitting devices. The distance between adjacent hollow structures is minimized to achieve optimal luminous efficiency of each top-emitting quantum dot light-emitting device with different luminous wavelengths.
  • Figures 14A to 14D are respectively several other planar schematic views of the metal reflective layer 7 in Figure 11.
  • the metal reflective layer 7 includes a plurality of independently arranged reflective portions 72 and a hollow structure 71 located between adjacent reflective portions 72 .
  • the distance between the reflective part 72 and the second electrode 2 can be regarded as a microcavity length.
  • the area where the hollow structure 71 is located The length of the microcavity is the distance between the electron transport layer 4 and the second electrode 2.
  • the area where the hollow structure 71 is located and the area where the reflective part 72 is located will form two microcavity lengths with two thicknesses.
  • the inventor of this case found that in the same The difference in length of the above two microcavities in the light-emitting device is within 5 nm, and the difference in microcavity length causes a shift of less than 1 nm in the luminescence peak position in the PL spectrum of the light-emitting device. Therefore, although the metal reflective layer 7 changes the spectrum of the emitted light, the change in the color purity of the device is within an acceptable range.
  • multiple reflective portions 72 can be distributed in an array, which can make the length of the microcavity of the device uniform and improve the color of the device. purity; and the production process can also be unified.
  • the shape of the reflective part 72 may be square; as shown in FIG. 14B , the shape of the reflective part 72 may be circular; as shown in FIG. As shown in 14C, the shape of the reflection part 72 may be triangular; of course, it is not limited to this.
  • the above-mentioned display substrate provided by the embodiment of the present disclosure also includes a plurality of data lines extending along the first direction and arranged along the second direction.
  • the plurality of reflective portions 72 may be along the A plurality of strip-shaped reflective parts extending in the second direction Y and arranged along the first direction X, the first direction It can improve the light extraction efficiency of the device.
  • the distance between adjacent reflective portions in each top-emitting quantum dot light-emitting device has a positive correlation trend with the emission wavelength of the top-emitting quantum dot light-emitting device. For example, the distance between adjacent reflective parts in a red top-emitting quantum dot light-emitting device is the largest, the distance between adjacent reflective parts in a green top-emitting quantum dot light-emitting device is second, and the distance between adjacent reflective parts in a blue top-emitting quantum dot light-emitting device is the largest. The distance between adjacent reflective parts is minimized to achieve optimal luminous efficiency of each top-emitting quantum dot light-emitting device with different luminous wavelengths.
  • the display substrate generally includes a plurality of sub-pixels, and a quantum dot light-emitting device is provided in each sub-pixel.
  • the arrangement structures of the several metal reflective layers 7 shown in FIGS. 13A to 14D provided by the embodiments of the present disclosure are all is the arrangement structure within a sub-pixel.
  • the metal reflective layer 7 embedded in the electron transmission layer 4 is divided into upper and lower parts.
  • the electron transport layer and the second metal layer located above the metal reflective layer 7 constitute the electron transport layer 4.
  • the sum of the thicknesses of the first electron transport layer and the second metal layer may be 50 nm to 80 nm, preferably 60 nm.
  • the thickness of the electron transport layer 4 corresponding to the area where the hollow structure 71 is located is 50 nm to 80 nm, preferably 60 nm. This thickness of the electron transport layer 4 can achieve optimal current efficiency.
  • FIG. 6 it also includes: located in the quantum dot light-emitting layer 3 and the second a hole transport layer 6 between the electrodes 2, and a hole injection layer 5 between the hole transport layer 6 and the second electrode 2.
  • the thickness of the hole transport layer 6 may be 10 nm to 40 nm.
  • the material of the hole transport layer 6 can be an organic transport layer such as polyvinylcarbazole (PVK), poly(9,9-dioctylfluorene-alt-N-(4-sec-butyl) Phenyl)-diphenylamine) (TFB), N,N'-diphenyl-N,N'-bis(3-methylbenzene)-(1,1'-biphenyl)-4,4'- Diamine (TPD), etc., can also be inorganic oxides such as NiOx, VOx, etc.
  • the hole transport layer 6 can be a single layer of material or a combination of multiple materials.
  • the embodiment of the present disclosure uses a combination of two materials.
  • the hole transport material in contact with the quantum dot light-emitting layer has a HOMO energy level between -5.5 and -6.2, which is close to the HOMO energy level of the quantum dot light-emitting layer, which is beneficial to Hole injection; the hole transport material far away from the quantum dot light-emitting layer has a HOMO energy level between -5.3 and -5.0.
  • the thickness of the hole injection layer 5 may be 3 nm to 7 nm. , preferably 5 nm; the material of the hole injection layer 5 can be organic materials such as PEDOT: PSS, HAT-CN, etc., or inorganic oxides such as MoOx, NiOx, CuOx, etc.
  • the thickness of the quantum dot light-emitting layer 3 may be 10 nm to 40 nm. , preferably 20nm ⁇ 30nm.
  • the materials of the quantum dot light-emitting layer 3 include but are not limited to CdS, CdSe, ZnSe, InP, PbS, CsPbCl 3 , CsPbBr 3 , CsPbI 3 , CdS/ZnS, CdSe/ZnSe, CdSe/ZnS, ZnSe, InP/ZnS, PbS/ Quantum dot materials such as ZnS, CsPbCl 3 /ZnS, CsPbBr 3 /ZnS or CsPhI 3 /ZnS.
  • holes and electrons are injected from the second electrode and the first electrode respectively, and after charge transfer, they reach the quantum dot light-emitting layer.
  • the conduction band and valence band of the quantum dot capture the electrons and holes respectively, and recombine to emit light. .
  • Quantum dot light-emitting devices can have either an upright structure or an inverted structure. The difference between the two lies in the different order of film layer production. Specifically, in the upright structure, the first electrode, the electron transport layer, and the quantum dot light-emitting layer are sequentially formed on the substrate. , a hole transport layer, a hole injection layer and a second electrode. The inverted structure is to sequentially form a second electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a first electrode on a substrate.
  • the top-emission quantum dot light-emitting devices shown in FIGS. 6 and 11 provided by embodiments of the present disclosure may have an inverted structure or an upright structure.
  • the metal reflective layer 7 in Figure 15 is planar as an example.
  • the top-emitting quantum dot light-emitting device also includes a substrate located on the side of the first electrode 1 facing away from the quantum dot light-emitting layer 3. 8;
  • the metal reflective layer 7 in Figure 16 is planar as an example, the top-emitting quantum dot light-emitting device substrate 8, and the second electrodes stacked sequentially on the substrate 8 2.
  • the substrate 8 may be a glass substrate, or a flexible substrate, such as polyethylene terephthalate (PET).
  • the light emitting direction of the device is away from the substrate.
  • the first electrode 1 close to the substrate 8 is an opaque electrode or includes an opaque film layer as a reflector.
  • Film layer, the second electrode 2 is a transparent electrode or a semi-transparent and semi-reflective film layer, which can allow light to pass through.
  • the material of the first electrode 1 can be opaque Al, Ag, Ti, Mo (thickness 60nm ⁇ 150nm), etc., or ITO, FTO or conductive polymer ( The thickness is 5 nm to 50 nm), etc.
  • the structure of the first electrode 1 is Ag (80 nm)/ITO (10 nm).
  • the material of the second electrode 2 may include Al, Ag, Mg:Ag alloy, etc., and the thickness of the second electrode 2 may be 10 nm to 20 nm; the material of the second electrode 2 may also be transparent conductive ITO, IZO, etc., and its thickness may be It is 40nm ⁇ 200nm.
  • the second electrode 2 close to the substrate 8 is an opaque electrode or includes an opaque film layer as a reflective film layer
  • the first electrode 1 is a transparent electrode or a semi-transparent and semi-reflective film layer. Let the light shine through.
  • the material of the second electrode 2 can be opaque Al, Ag, Ti, Mo (thickness 60nm ⁇ 150nm), etc., or ITO, FTO or conductive polymer ( The thickness is 5 nm to 50 nm), etc.
  • the structure of the second electrode 2 is Ag (80 nm)/ITO (10 nm).
  • the material of the first electrode 1 may include Al, Ag, Mg:Ag alloy, etc., and the thickness of the first electrode 1 may be 10 nm to 20 nm; the material of the first electrode 1 may also be transparent conductive ITO, IZO, etc., and its thickness may be It is 40nm ⁇ 200nm.
  • the above-mentioned display substrate provided by the embodiment of the present disclosure also includes a light extraction layer (capping layer) located on the light extraction side of the top-emitting quantum dot light-emitting device.
  • the material of the layer can be organic material, and the thickness of the light extraction layer can be 40 nm to 90 nm, preferably 70 nm. In this case, the luminous efficiency of the device is better.
  • the light extraction layer 9 is located on the side of the second electrode 2 facing away from the substrate 8 ; as shown in FIG. 16 , the light extraction layer 9 is located on the side of the first electrode 1 facing away from the substrate 8 .
  • the substrate 8 may include a stacked substrate, a driving circuit, a passivation layer, a planarization layer and other structures.
  • embodiments of the present disclosure also provide a method for manufacturing the above-mentioned display substrate, including:
  • each top-emitting quantum dot light-emitting device includes: a first electrode and a second electrode arranged oppositely, a quantum dot light-emitting layer located between the first electrode and the second electrode, and An electron transport layer is located between the first electrode and the quantum dot light-emitting layer; the electron transport layer has a metal reflective layer inside.
  • the above-mentioned manufacturing method of the display substrate provided by the embodiment of the present disclosure disposes a metal reflective layer inside the electron transmission layer.
  • the metal reflective layer has a certain reflectivity and a certain transmittance. Therefore, the metal reflective layer can adjust the microcavity of the device. Length, for example, for devices with different emitting colors, you can set the position of the metal reflective layer in the electron transmission layer (such as the distance between the metal reflective layer and the first electrode) so that the microcavity length corresponding to the devices with different emitting colors is the light extraction efficiency.
  • microcavity length when the current efficiency is optimal since the microcavity length can be adjusted by adjusting the position of the metal reflective layer in the electron transmission layer, the thickness of the electron transmission layer can be set to the thickness range corresponding to the optimal current efficiency, thus This prevents the device from leakage problems. Therefore, embodiments of the present disclosure can achieve optimal light extraction efficiency and optimal current efficiency of the device at the same time.
  • the substrate 8 can be glass or a flexible PET substrate.
  • the material and thickness of the first electrode 1 refer to the description of the aforementioned display substrate.
  • the material of the first electron transport layer 41 may be ZnO or ZnMgO.
  • the material of the metal reflective layer 7 can be Mg, Ag, Al, etc., and the thickness can be 3nm-5nm.
  • the distance between the metal reflective layer 7 and the first electrode 1 is different. Please refer to the description of the aforementioned display substrate.
  • the second electron transport layer 42 and the first electron transport layer 41 constitute the electron transport layer 4; the material of the second electron transport layer 42 Can be ZnO or ZnMgO.
  • each film layer in the quantum dot light-emitting device includes but are not limited to spin coating, evaporation, chemical vapor deposition, physical vapor deposition, magnetron sputtering, inkjet printing, electrospray One or more of printing methods, etc.
  • the embodiments of the present disclosure mainly use a quantum dot light-emitting device with an inverted structure as an example to describe the manufacturing method of the quantum dot light-emitting device in detail.
  • the manufacturing method of the quantum dot light-emitting device with an upright structure is only The film layer production sequence has changed and will not be described in detail here.
  • an embodiment of the present disclosure also provides a display device, including the above display substrate provided by an embodiment of the present disclosure.
  • the display device can be: a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, a navigator, or any other product or component with a display function.
  • Other essential components of the display device are understood by those of ordinary skill in the art, and will not be described in detail here, nor should they be used to limit the present invention. Since the problem-solving principle of this display device is similar to that of the foregoing display substrate, the implementation of this display device can be referred to the implementation of the foregoing display substrate, and repeated descriptions will not be repeated.
  • the above-mentioned display device provided by the embodiments of the present disclosure may also include other film layers well known to those skilled in the art, which will not be described in detail here.
  • the above-mentioned display substrate, its manufacturing method and display device provided by the embodiments of the present disclosure provide a metal reflective layer inside the electron transmission layer.
  • the metal reflective layer can adjust the microcavity length of the device, for example, while ensuring the electrical balance of the device. Adjust the corresponding microcavity length (not suitable for light extraction) when the current efficiency is large (the electron transport layer is thick) to a more appropriate microcavity length (reduce the microcavity length, which is beneficial to light extraction), and pass the metal reflection layer and the third
  • the microcavity between the two electrodes regulates the light emission from the device, and the thickness of the electron transport layer between the metal reflective layer and the quantum dot light-emitting layer can be reduced to achieve optimal light extraction efficiency.
  • an electron transport layer between the metal reflective layer and the first electrode.
  • This part of the electron transport layer can be used to adjust the electrical balance of the device so that the thickness of the electron transport layer in the device is not too low and the device can achieve electrical balance. Therefore, embodiments of the present disclosure can achieve optimal light extraction efficiency and optimal current efficiency of the device at the same time.

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Abstract

本公开实施例公开了一种显示基板、其制作方法及显示装置，包括多个顶发射量子点发光器件，每一顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于第一电极和第二电极之间的量子点发光层，以及位于第一电极和量子点发光层之间的电子传输层；其中，电子传输层的内部具有金属反射层。

Description

一种显示基板、其制作方法及显示装置 技术领域
本公开涉及显示技术领域，特别涉及一种显示基板、其制作方法及显示装置。
背景技术
量子点(Quantum Dot，简称QD)作为新型的发光材料，具有光色纯度高、发光量子效率高、发光颜色可调、使用寿命长等优点，已成为目前新型发光二级管中发光材料的研究热点。因此，以量子点材料作为发光层的量子点发光二极管(Quantum Dot Light Emitting Diodes，简称QLED)成为了目前新型显示器件研究的主要方向。
发明内容
本公开实施例提供了一种显示基板、其制作方法及显示装置，具体方案如下：
本公开实施例提供的一种显示基板，包括多个顶发射量子点发光器件，每一所述顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于所述第一电极和所述第二电极之间的量子点发光层，以及位于所述第一电极和所述量子点发光层之间的电子传输层；其中，
所述电子传输层的内部具有金属反射层。
可选地，在本公开实施例提供的上述显示基板中，每一所述顶发射量子点发光器中的所述金属反射层的面积与所述电子传输层的面积之比为50％～100％。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层所在平面与所述电子传输层所在平面之间的夹角小于1‰度。
可选地，在本公开实施例提供的上述显示基板中，所述多个顶发射量子点发光器件包括多个不同发光波长的顶发射量子点发光器件，各所述顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离与该所述顶发射量子点发光器件的发光波长呈反相关趋势。
可选地，在本公开实施例提供的上述显示基板中，所述多个不同发光波长的顶发射量子点发光器件包括红色顶发射量子点发光器件、绿色顶发射量子点发光器件和蓝色顶发射量子点发光器件，所述红色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第一距离，所述绿色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第二距离，所述蓝色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第三距离；其中，所述第一距离为0～20nm，所述第二距离为20nm～40nm，所述第三距离为40nm～60nm。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层为面状结构。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层的面积小于所述电子传输层的面积，且所述金属反射层位于所述电子传输层的中心区域。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层包括独立设置的多个镂空结构。
可选地，在本公开实施例提供的上述显示基板中，所述多个镂空结构呈阵列分布。
可选地，在本公开实施例提供的上述显示基板中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，所述多个镂空结构为沿所述第二方向延伸且沿所述第一方向排列的多个条状镂空结构，所述第一方向和所述第二方向交叉设置。
可选地，在本公开实施例提供的上述显示基板中，各所述顶发射量子点发光器件中的相邻所述镂空结构之间的距离与该所述顶发射量子点发光器件 的发光波长呈正相关趋势。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层包括独立设置的多个反射部以及位于相邻所述反射部之间的镂空结构。
可选地，在本公开实施例提供的上述显示基板中，所述多个反射部呈阵列分布。
可选地，在本公开实施例提供的上述显示基板中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，所述多个反射部为沿所述第二方向延伸且沿所述第一方向排列的多个条状反射部，所述第一方向和所述第二方向交叉设置。
可选地，在本公开实施例提供的上述显示基板中，各所述顶发射量子点发光器件中的相邻所述反射部之间的距离与该所述顶发射量子点发光器件的发光波长呈正相关趋势。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层在可见光范围内的反射率为30％～60％。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层的功函数为2.2eV～4.2eV，所述金属反射层的厚度为3nm～5nm。
可选地，在本公开实施例提供的上述显示基板中，所述金属反射层的材料包括Mg、Ag、Al。
可选地，在本公开实施例提供的上述显示基板中，所述电子传输层的材料包括金属氧化物纳米粒子，所述金属反射层背离所述第一电极的表面凹凸不平。
可选地，在本公开实施例提供的上述显示基板中，所述电子传输层与所述第一电极接触的表面的氧空位比例小于所述电子传输层与所述金属反射层接触的表面的氧空位比例。
可选地，在本公开实施例提供的上述显示基板中，所述电子传输层的厚度为50nm～80nm。
可选地，在本公开实施例提供的上述显示基板中，还包括：位于所述量 子点发光层和所述第二电极之间的空穴传输层，以及位于所述空穴传输层和所述第二电极之间的空穴注入层。
可选地，在本公开实施例提供的上述显示基板中，所述空穴传输层的厚度为10nm～40nm，所述空穴注入层的厚度为3nm～7nm，所述量子点发光层的厚度为10nm～40nm。
相应地，本公开实施例还提供了一种显示装置，包括本公开实施例提供的上述任一项所述的显示基板。
相应地，本公开实施例还提供了一种用于制作本公开实施例提供的上述任一项所述的显示基板的制作方法，包括：
制作多个顶发射量子点发光器件；其中，每一所述顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于所述第一电极和所述第二电极之间的量子点发光层，以及位于所述第一电极和所述量子点发光层之间的电子传输层；所述电子传输层的内部具有金属反射层。
可选地，在本公开实施例提供的上述制作方法中，制作所述电子传输层和所述金属反射层，具体为：
形成第一电子传输层；
在所述第一电子传输层上形成金属反射层；
在所述金属反射层上形成第二电子传输层；所述第二电子传输层和所述第一电子传输层构成所述电子传输层。
附图说明
图1为相关技术中一种顶发射量子点发光器件的结构示意图；
图2为图1对应的红色量子点发光器件中电子传输层取不同厚度时对应的出光角度分布模拟示意图；
图3为图1对应的绿色量子点发光器件中电子传输层取不同厚度时对应的出光角度分布模拟示意图；
图4为图1对应的蓝色量子点发光器件中电子传输层取不同厚度时对应的 出光角度分布模拟示意图；
图5为图1对应的绿色量子点发光器件中电子传输层取不同厚度时对应的电流效率-电压示意图；
图6为本公开实施例提供的一种顶发射量子点发光器件的结构示意图；
图7A为本公开实施例提供的一种红色顶发射量子点发光器件的结构示意图；
图7B为本公开实施例提供的一种绿色顶发射量子点发光器件的结构示意图；
图7C为本公开实施例提供的一种蓝色顶发射量子点发光器件的结构示意图；
图8为本公开实施例提供的又一种顶发射量子点发光器件的结构示意图；
图9为图6中金属反射层的平面示意图；
图10为本公开实施例提供的又一种顶发射量子点发光器件的结构示意图；
图11为本公开实施例提供的又一种顶发射量子点发光器件的结构示意图；
图12A为本公开实施例提供的又一种红色顶发射量子点发光器件的结构示意图；
图12B为本公开实施例提供的又一种绿色顶发射量子点发光器件的结构示意图；
图12C为本公开实施例提供的又一种蓝色顶发射量子点发光器件的结构示意图；
图13A-图13D分别为图11中金属反射层的几种平面示意图；
图14A-图14D分别为图11中金属反射层的另外几种平面示意图；
图15为本公开实施例提供的一种倒置顶发射量子点发光器件的结构示意图；
图16为本公开实施例提供的一种正置顶发射量子点发光器件的结构示意图；
图17A-图17H分别为本公开实施例提供的一种显示基板的制作方法在执 行每一制作步骤之后的结构示意图。
具体实施方式
为使本公开实施例的目的、技术方案和优点更加清楚，下面将结合本公开实施例的附图，对本公开实施例的技术方案进行清楚、完整地描述。显然，所描述的实施例是本公开的一部分实施例，而不是全部的实施例。并且在不冲突的情况下，本公开中的实施例及实施例中的特征可以相互组合。基于所描述的本公开的实施例，本领域普通技术人员在无需创造性劳动的前提下所获得的所有其他实施例，都属于本公开保护的范围。
除非另外定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“包括”或者“包含”等类似的词语意指出现该词前面的元件或者物件涵盖出现在该词后面列举的元件或者物件及其等同，而不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电性的连接，不管是直接的还是间接的。“内”、“外”、“上”、“下”等仅用于表示相对位置关系，当被描述对象的绝对位置改变后，则该相对位置关系也可能相应地改变。
需要注意的是，附图中各图形的尺寸和形状不反映真实比例，目的只是示意说明本公开内容。并且自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。
目前，主动式电致量子点发光显示产品(AMQLED)由于其在宽色域、高寿命等方面的潜在优势也得到了越来越广泛的关注，其研究日益深入，量子效率不断提升，基本达到产业化的水平，进一步采用新的工艺和技术来实现其产业化已成为未来的趋势。
在QLED器件结构中，由于能级位置、迁移率等原因，器件中载流子注入不平衡，需要调节电子空穴注入的平衡提升器件效率。由于电子注入普遍优于空穴注入，电子在载流子数目中占据优势，因此除增加空穴注入的方式之 外，通常采用抑制过剩电子注入的方式来实现电荷平衡，此时对于电子传输层的厚度有一定要求，不能太薄。
目前对QLED研究较多的是底发射结构，在高分辨率显示产品对高分辨率的需求，要求QLED器件采用顶发射结构，顶发射结构可以提高开口率。同时需要通过优化各膜层厚度，使得器件最佳的电学结构和光学结构得以统一，同时优化电学平衡和出光效率，而这很难达到统一。对于红绿蓝三种子像素，若想取得最佳出光效率，对于腔长的要求差异明显。通常而言，红色QLED器件腔长最大，约140nm左右，蓝色QLED器件腔长最小，约75nm左右。对于红色QLED器件，由于腔长较大，其在合适的腔长范围内有较大的调节空间可以优化电学结构，其各层膜厚也可以较大，因此较容易达到电学平衡。而对于蓝色QLED器件，其合适的腔长范围内各层膜厚较小，调节电学平衡的空间较小；同时由于蓝色QLED器件腔长较小，各层膜厚小，还会带来器件漏电的问题，进一步影响电学平衡。
如图1所示，图1为相关技术中的一种顶发射QLED器件的结构示意图，包括：相对设置的第一电极1和第二电极2，位于第一电极1和第二电极2之间的量子点发光层3，位于第一电极1和量子点发光层3之间的电子传输层4，位于第二电极2和量子点发光层3之间的空穴注入层5，以及位于量子点发光层3和空穴注入层5之间的空穴传输层6。经本案的发明人研究发现，当量子点发光层3的厚度为30nm，空穴传输层6的厚度为40nm，空穴注入层5的厚度为7nm时，QLED器件的电学平衡较好。下面以量子点发光层3的厚度为30nm，空穴传输层6的厚度为40nm，空穴注入层5的厚度为7nm，分别对红色、绿色和蓝色QLED器件采用不同厚度的电子传输层4时对出光效率的影响进行模拟，如图2-图4所示，图2为图1对应的QLED器件为红色QLED器件，电子传输层4取不同厚度(20nm、40nm、60nm、70nm、80nm)时对应的出光角度分布模拟示意图，此时不同厚度的电子传输层4对应的腔长分别约为100nm、120nm、140nm、150nm、160nm。从图2可以看出，其最佳出光效率为电子传输层4的厚度为60nm(即腔长为140nm)时。图3为图1对应的QLED器件为绿色QLED 器件，电子传输层4取不同厚度(20nm、30nm、40nm、50nm、60nm)时对应的出光角度分布模拟示意图，此时不同厚度的电子传输层4对应的腔长分别约为100nm、110nm、120nm、130nm、140nm。从图3可以看出，其最佳出光效率为电子传输层4的厚度为40nm(即腔长为120nm)时。图4为图1对应的QLED器件为蓝色QLED器件，电子传输层4取不同厚度(10nm、20nm、30nm、40nm、50nm)时对应的出光角度分布模拟示意图，此时不同厚度的电子传输层4对应的腔长分别约为90nm、100nm、110nm、120nm、130nm。从图4可以看出，其最佳出光效率为电子传输层4的厚度为20nm(即腔长为100nm)时。因此，红色、绿色和蓝色QLED器件的电子传输层4的厚度为分别为60nm、40nm、20nm时有最佳的出光效率。但是，器件的出光效率最佳时其电流效率不一定最佳，以绿色QLED器件为例，如图5所示，图5为图1对应的QLED器件为绿色QLED器件，电子传输层4(ZnO表示)取不同厚度(40nm、50nm、60nm、70nm)时对应的电流效率-电压示意图，此时不同厚度的电子传输层4对应的腔长分别约为120nm、130nm、140nm、150nm，由于图3中当电子传输层4的厚度为40nm出光效率最佳，但是图5中电子传输层4的厚度为40nm时器件电流效率却最差，因此在器件的光学性能最佳时，器件的电学性能却最差，主要原因是当电子传输层4的厚度为40nm时，此时厚度较低，电子注入过多，器件电学平衡最差，进而影响了器件总体性能。另外，蓝色QLED器件的电子传输层4的厚度为20nm时出光效率最佳，但是此时电子传输层4的厚度较薄，造成器件的漏电较大，对器件的电学影响进一步增大。因此如何找到一个合适的器件结构，统一器件的最佳电学和光学结构，是本领域技术人员亟需解决的技术问题。
有鉴于此，本公开实施例提供了一种显示基板，包括多个顶发射量子点发光器件，如图6所示，图6仅示意出其中一个顶发射量子点发光器件的结构，每一顶发射量子点发光器件包括：相对设置的第一电极1和第二电极2，位于第一电极1和第二电极2之间的量子点发光层3，以及位于第一电极1和量子点发光层3之间的电子传输层4；其中，
电子传输层4的内部具有金属反射层7。
本公开实施例提供的上述阵列基板，通过在电子传输层的内部设置金属反射层，金属反射层可以调节器件的微腔长度，例如在保证器件电学平衡的情况下，将电流效率较大(电子传输层较厚)时对应的微腔长度(不适合光取出)调整为较合适的微腔长度(减小微腔长度，利于光取出)，通过金属反射层和第二电极之间的微腔调节器件出光，金属反射层和量子点发光层之间的电子传输层厚度可以较低，从而达到最优出光效率。同时，金属反射层与第一电极之间仍有电子传输层，此部分电子传输层可以用来调节器件的电学平衡，使得器件中电子传输层的厚度不至于过低，器件可以达到电学平衡。因此本公开实施例可以同时实现器件的出光效率最佳和电流效率最佳。
在具体实施时，为了保证金属反射层能够起到调节器件的微腔长度的功能，在本公开实施例提供的上述显示基板中，每一顶发射量子点发光器中的金属反射层的面积与电子传输层的面积之比可以为50％～100％。例如，金属反射层的面积与电子传输层的面积之比可以为50％、60％、70％、80％、90％、100％等。
在具体实施时，为了提高器件的出光效果，金属反射层所在平面与电子传输层所在平面一般设计成平行的，但是由于制作工艺中存在误差，例如来源于膜厚分布的不均匀性，金属反射层所在平面与电子传输层所在平面可能不完全平行，在本公开实施例提供的上述显示基板中，金属反射层所在平面与电子传输层所在平面之间的夹角小于1‰度。
在具体实施时，在本公开实施例提供的上述显示基板中，如图7A-图7C所示，多个顶发射量子点发光器件包括多个不同发光波长的顶发射量子点发光器件(例如图7A对应一种发光波长，图7B对应另一种发光波长，图7C对应又一种发光波长)，由于发光波长越小，器件的最佳微腔长度(金属反射层7与第二电极2之间的距离)越小，因此各顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离与该顶发射量子点发光器件的发光波长呈反相关趋势，例如，图7A所示的顶发射量子点发光器件的发光波长最大，图7B所示的顶发射量子点发光器件的发光波长次之，图7C所示的顶发射量子点发光器件 的发光波长最小，则图7A所示的顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离最小，图7B所示的顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离次之，图7C所示的顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离最大，从而可以实现不同发光波长的器件均能够保证最佳出光效率。
在具体实施时，在本公开实施例提供的上述显示基板中，如图7A-图7C所示，多个不同发光波长的顶发射量子点发光器件可以包括红色顶发射量子点发光器件(图7A所示)、绿色顶发射量子点发光器件(图7B所示)和蓝色顶发射量子点发光器件(图7C所示)，红色顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离为第一距离D1，绿色顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离为第二距离D2，蓝色顶发射量子点发光器件中的金属反射层7与第一电极1之间的距离为第三距离D3，第一距离D1小于第二距离D2，第二距离D2小于第三距离D3。这样通过设置金属反射层7在不同发光颜色的器件中的电子传输层4内的位置，使得不同发光颜色的器件对应的微腔长度为出光效率最佳时对应的微腔长度；由于可以通过调节金属反射层7在电子传输层4中的位置来调节微腔长度，因此可以将电子传输层4的厚度设置成电流效率较佳时对应的厚度范围，从而使得器件不会发生漏电的问题。
在具体实施时，在本公开实施例提供的上述显示基板中，如图7A所示，第一距离D1可以为0～20nm，金属反射层7与量子点发光层3之间的距离在60nm左右；如图7B所示，第二距离D2可以为20nm～40nm，金属反射层7与量子点发光层3之间的距离在40nm左右；如图7C所示，第三距离D3可以为40nm～60nm，金属反射层7与量子点发光层3之间的距离在20nm左右。第一距离D1、第二距离D2和第三距离D3的范围设置可以使得器件的电学性能和光学性能均较佳。
在具体实施时，在本公开实施例提供的上述显示基板中，金属反射层在可见光范围内的反射率可以在30％～60％范围内，即金属反射层具有一定的透 过率和一定的反射率，可以对器件的微腔长度进行调节。
在具体实施时，在本公开实施例提供的上述显示基板中，金属反射层的功函数可以为2.2eV～4.2eV，金属反射层的厚度可以为3nm～5nm。该厚度范围内的金属反射层不会影响器件的电学性能。
在具体实施时，在本公开实施例提供的上述显示基板中，金属反射层的材料可以包括但不限于Mg、Ag、Al等金属。
在具体实施时，在本公开实施例提供的上述显示基板中，电子传输层的材料可以包括金属氧化物纳米粒子，例如ZnO或ZnMgO等，电子传输层4一般采用溅射或蒸镀的方式制备，为了降低制作工艺复杂度，金属反射层7可以采用和电子传输层4相同的制备工艺，例如均采用溅射的方式，在电子传输层溅射时，增加一步金属的溅射即可，不用增加其它设备，工艺复杂度不会增加；如图8所示，由于电子传输层4的材料为金属氧化物纳米粒子，因此与第一电极1接触的电子传输层4的背离第一电极1的表面凹凸不平，则金属反射层7背离第一电极1的表面也凹凸不平，金属反射层7的凹凸不平的表面可以对发射光线进行折射、反射，以提升出光效率。
需要说明的是，本公开实施例图8仅是为了示意性说明电子传输层4和金属反射层7的表面是凹凸不平的结构，不代表真实的凹凸表面的结构。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6所示，金属反射层7中与电子传输层4接触的表面的金属原子(M表示)可能与电子传输层4中的O原子之间形成化学键，例如形成M-O键，表面形成的M-O键不会造成金属反射层7整体膜层形成氧化物，金属反射层7内部仍为金属成分，具有反射性；并且，形成的M-O键可以增加电子传输层4中的氧空位比例，即电子传输层4与第一电极1接触的表面的氧空位比例小于电子传输层4与金属反射层7接触的表面的氧空位比例，这样可以降低电子传输层4的电子导电性，从而可以降低器件中的电子注入效率，改善载流子注入平衡。
在具体实施时，在本公开实施例提供的上述显示基板中，如图9所示，图9为图6中金属反射层7的平面示意图，该金属反射层7为面状结构。具 体地，该金属反射层7的面积可以与电子传输层4的面积相等。
在具体实施时，在本公开实施例提供的上述显示基板中，如图10所示，图10为本公开实施例提供的顶发射发光器件的另一种截面示意图，其中金属反射层7为面状结构，金属反射层7的面积可以小于电子传输层4的面积，且金属反射层7位于电子传输层4的中心区域，这样边缘区域的电子传输层4为一体结构，可以保证电子传输层4的连续性，提高电学性能；并且，金属反射层7缩短腔长，可以使视角更加集中在正面出光，降低侧面出光。
具体地，针对图10所示的金属反射层7的结构，对于不同发光波长的器件中金属反射层7的设计位置可以参见图6所示的设计位置方式。
在具体实施时，在本公开实施例提供的上述显示基板中，如图11、图12A-图12C、13A-图13D所示，图11为本公开实施例提供的顶发射发光器件的另一种截面示意图，图12A-图12C分别为图11对应的结构中量子点发光层为红色量子点发光层、绿色量子点发光层、蓝色量子点发光层时的截面示意图，图13A-图13D分别为图11中金属反射层7的几种平面示意图，该金属反射层7包括独立设置的多个镂空结构71。具体地，具有镂空结构71的金属反射层7保留其光反射效果，并且镂空结构71可以保证电子传输层4的连续性，提高电学性能。另外，在同一个发光器件中，由于金属反射层7具有镂空结构71，金属反射层7的反光部分(相邻镂空结构71之间的部分)与第二电极2之间的距离可以看成是一种微腔长度，镂空结构71所在区域的微腔长度为电子传输层4和第二电极2之间的距离，即镂空结构71所在区域和金属反射层7的反光部分会形成两种厚度的微腔长度，但是本案的发明人研究发现在同一个发光器件内的上述两种微腔长度差异在5nm以内，该微腔长度差异对于发光器件的PL光谱中发光峰位的偏移量不足1nm。因此，尽管金属反射层7改变了出光的光谱，但是对于器件色纯度的改变在可以接受的范围内。
需要说明的是，图11和图6的区别在于金属反射层7的结构不同，图12A-图12C与图7A-图7C的区别在于金属反射层7的结构不同，其余结构相同。
在具体实施时，在本公开实施例提供的上述显示基板中，如图13A-图13C 所示，多个镂空结构71可以呈阵列分布，这样可以使得器件的微腔长度均一，提高器件的色纯度；并且还可以统一制作工艺。
在具体实施时，在本公开实施例提供的上述显示基板中，如图13A所示，镂空结构71的形状可以为方形；如图13B所示，镂空结构71的形状可以为圆形；如图13C所示，镂空结构71的形状可以为三角形；当然，不限于此。
在具体实施时，在本公开实施例提供的上述显示基板中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，如图13D所示，多个镂空结构71可以为沿第二方向Y延伸且沿第一方向X排列的多个条状镂空结构，第一方向X和第二方向Y交叉设置，即数据线的延伸方向与条状镂空结构的延伸方向垂直设置，这样可以提高器件的出光效率。
在具体实施时，针对不同发光波长的顶发射量子点发光器件，各顶发射量子点发光器件中的相邻镂空结构之间的距离与该顶发射量子点发光器件的发光波长呈正相关趋势。例如红色顶发射量子点发光器件中的相邻镂空结构之间的距离最大，绿色顶发射量子点发光器件中的相邻镂空结构之间的距离次之，蓝色顶发射量子点发光器件中的相邻镂空结构之间的距离最小，以实现不同发光波长的各顶发射量子点发光器件的发光效率均达到最佳。
在具体实施时，在本公开实施例提供的上述显示基板中，如图14A-图14D所示，图14A-图14D分别为图11中金属反射层7的另外几种平面示意图，该金属反射层7包括独立设置的多个反射部72以及位于相邻反射部72之间的镂空结构71。这样在同一个发光器件中，由于金属反射层7具有镂空结构71和反射部72，反射部72与第二电极2之间的距离可以看成是一种微腔长度，镂空结构71所在区域的微腔长度为电子传输层4和第二电极2之间的距离，即镂空结构71所在区域和反射部72所在区域会形成两种厚度的微腔长度，但是本案的发明人研究发现在同一个发光器件内的上述两种微腔长度差异在5nm以内，该微腔长度差异对于发光器件的PL光谱中发光峰位的偏移量不足1nm。因此，尽管金属反射层7改变了出光的光谱，但是对于器件色纯度的改变在可以接受的范围内。
在具体实施时，在本公开实施例提供的上述显示基板中，如图14A-图14C所示，多个反射部72可以呈阵列分布，这样可以使得器件的微腔长度均一，提高器件的色纯度；并且还可以统一制作工艺。
在具体实施时，在本公开实施例提供的上述显示基板中，如图14A所示，反射部72的形状可以为方形；如图14B所示，反射部72的形状可以为圆形；如图14C所示，反射部72的形状可以为三角形；当然，不限于此。
在具体实施时，在本公开实施例提供的上述显示基板中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，如图14D所示，多个反射部72可以为沿第二方向Y延伸且沿第一方向X排列的多个条状反射部，第一方向X和第二方向Y交叉设置，即数据线的延伸方向与条状反射部的延伸方向垂直设置，这样可以提高器件的出光效率。
在具体实施时，针对不同发光波长的顶发射量子点发光器件，各顶发射量子点发光器件中的相邻反射部之间的距离与该顶发射量子点发光器件的发光波长呈正相关趋势。例如红色顶发射量子点发光器件中的相邻反射部之间的距离最大，绿色顶发射量子点发光器件中的相邻反射部之间的距离次之，蓝色顶发射量子点发光器件中的相邻反射部之间的距离最小，以实现不同发光波长的各顶发射量子点发光器件的发光效率均达到最佳。
需要说明的是，显示基板一般包括多个子像素，每一子像素内设置一量子点发光器件，本公开实施例提供的图13A-图14D所示的几种金属反射层7的排布结构均为一个子像素内的排布结构。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6所示，电子传输层4中内嵌的金属反射层7分为上下两部分，位于金属反射层7下方的第一电子传输层和位于金属反射层7上方的第二金属层构成电子传输层4，第一电子传输层和第二金属层的厚度之和可以为50nm～80nm，优选60nm。如图11所示，镂空结构71所在区域对应的电子传输层4的厚度为50nm～80nm，优选60nm。该厚度的电子传输层4可以实现最佳的电流效率。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6、图7A- 图7C、图11和图12A-图12C所示，还包括：位于量子点发光层3和第二电极2之间的空穴传输层6，以及位于空穴传输层6和第二电极2之间的空穴注入层5。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6、图7A-图7C、图11和图12A-图12C所示，空穴传输层6的厚度可以为10nm～40nm，优选为25nm～35nm；空穴传输层6的材料可以是有机传输层如聚乙烯基咔唑(PVK)、聚(9,9-二辛基芴-alt-N-(4-仲丁基苯基)-二苯胺)(TFB)、N,N’-二苯基-N,N’-二(3-甲基苯)-(1,1’-联苯基)-4,4’-二胺(TPD)等，也可以是无机氧化物如NiOx、VOx等。空穴传输层6可以是单层材料，亦可以是多种材料组合。本公开实施例采用两种材料组合而成，其中与量子点发光层接触的空穴传输材料，其HOMO能级在-5.5～-6.2之间，与量子点发光层的HOMO能级接近，利于空穴注入；远离量子点发光层的空穴传输材料，其HOMO能级在-5.3～-5.0之间。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6、图7A-图7C、图11和图12A-图12C所示，空穴注入层5的厚度可以为3nm～7nm，优选5nm；空穴注入层5的材料可以为有机材料如PEDOT：PSS、HAT-CN等，也可以是无机氧化物如MoOx、NiOx、CuOx等。
在具体实施时，在本公开实施例提供的上述显示基板中，如图6、图7A-图7C、图11和图12A-图12C所示，量子点发光层3的厚度可以为10nm～40nm，优选20nm～30nm。量子点发光层3的材料包括但不限于CdS、CdSe、ZnSe、InP、PbS、CsPbCl 3、CsPbBr 3、CsPbI 3、CdS/ZnS、CdSe/ZnSe、CdSe/ZnS、ZnSe、InP/ZnS、PbS/ZnS、CsPbCl 3/ZnS、CsPbBr 3/ZnS或CsPhI 3/ZnS等量子点材料。
在本公开实施例中，空穴和电子分别从第二电极和第一电极注入，经过电荷传输后到达量子点发光层，量子点的导带和价带分别俘获电子和空穴，并复合发光。
量子点发光器件可以为正置结构，也可以为倒置结构，二者区别在于膜 层制作顺序不同，具体为：正置结构是在基底上依次形成第一电极、电子传输层、量子点发光层、空穴传输层、空穴注入层和第二电极，倒置结构是在基底上依次形成第二电极、空穴注入层、空穴传输层、量子点发光层、电子传输层和第一电极。
本公开实施例提供的图6和图11所示的顶发射量子点发光器件可以为倒置结构，也可以为正置结构。当为倒置结构时，如图15所示，图15的金属反射层7以面状为例，该顶发射量子点发光器件还包括位于第一电极1背向量子点发光层3一侧的基底8；当为正置结构时，如图16所示，图16的金属反射层7以面状为例，该顶发射量子点发光器件基底8，以及位于基底8上依次层叠设置的第二电极2、空穴注入层5、空穴传输层6、量子点发光层3、电子传输层4和第一电极1。该基底8可以是玻璃基底，或者是柔性基底，如聚对苯二甲酸乙二醇酯(PET)。
对于顶发射结构来说，器件的出光方向为背离基底方向出光，具体地，当为倒置结构时，如图15所示，靠近基底8的第一电极1为不透明电极或包括不透明膜层作为反射膜层，第二电极2为透明电极或半透半反膜层，可以让光线透过。具体地，第一电极1的材料可以是不透明的Al、Ag、Ti、Mo(厚度为60nm～150nm)等，还可以在Al、Ag、Ti或Mo的上方沉积ITO、FTO或者导电聚合物(厚度为5nm～50nm)等，本公开实施例优选第一电极1的结构为Ag(80nm)/ITO(10nm)。第二电极2的材料可以包括Al、Ag、Mg:Ag合金等，第二电极2的厚度可以是10nm～20nm；第二电极2的材料也可以采用透明导电的ITO、IZO等，其厚度可以为40nm～200nm。
当为正置结构时，如图16所示，靠近基底8的第二电极2为不透明电极或包括不透明膜层作为反射膜层，第一电极1为透明电极或半透半反膜层，可以让光线透过。具体地，第二电极2的材料可以是不透明的Al、Ag、Ti、Mo(厚度为60nm～150nm)等，还可以在Al、Ag、Ti或Mo的上方沉积ITO、FTO或者导电聚合物(厚度为5nm～50nm)等，本公开实施例优选第二电极2的结构为Ag(80nm)/ITO(10nm)。第一电极1的材料可以包括Al、Ag、 Mg:Ag合金等，第一电极1的厚度可以是10nm～20nm；第一电极1的材料也可以采用透明导电的ITO、IZO等，其厚度可以为40nm～200nm。
在具体实施时，为了进一步提高量子点发光器件的出光效率，在本公开实施例提供的上述显示基板中，还包括位于顶发射量子点发光器件出光侧的光取出层(capping layer)，光取出层的材料可以为有机材料，光取出层的厚度可以为40nm～90nm，优选70nm，此时器件的发光效率较佳。具体地，如图15所示，光取出层9位于第二电极2背离基底8的一侧；如图16所示，光取出层9位于第一电极1背离基底8的一侧。
如图15和图16所示，基底8可以包括层叠设置的衬底基板、驱动电路、钝化层、平坦层等结构。
基于同一发明构思，本公开实施例还提供了一种上述显示基板的制作方法，包括：
制作多个顶发射量子点发光器件；其中，每一顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于第一电极和第二电极之间的量子点发光层，以及位于第一电极和量子点发光层之间的电子传输层；电子传输层的内部具有金属反射层。
本公开实施例提供的上述显示基板的制作方法，通过在电子传输层的内部设置金属反射层，金属反射层具有一定的反射率和一定的透过率，因此金属反射层可以调节器件的微腔长度，例如对于不同发光颜色的器件，可以通过设置金属反射层在电子传输层中的位置(例如金属反射层距离第一电极的距离)，使得不同发光颜色的器件对应的微腔长度为出光效率最佳时对应的微腔长度；由于可以通过调节金属反射层在电子传输层中的位置来调节微腔长度，因此可以将电子传输层的厚度设置成电流效率较佳时对应的厚度范围，从而使得器件不会发生漏电的问题。因此本公开实施例可以同时实现器件的出光效率最佳和电流效率最佳。
下面以图15所示的倒置结构的顶发射量子点发光器件为例，对本公开实施例提供的显示基板的制作方法进行详细说明：
(1)在基底8上沉积第一电极1，如图17A所示；该基底8可以是玻璃、或者是柔性PET基底，第一电极1的材料及厚度参见前述一种显示基板中的描述。
(2)在第一电极1上形成第一电子传输层41，如图17B所示；第一电子传输层41的材料可以是ZnO或ZnMgO。
(3)在第一电子传输层41上形成金属反射层7，如图17C所示；金属反射层7的材料可以为Mg、Ag、Al等，厚度可以为3nm-5nm。对于不同发光颜色的量子点发光器件，金属反射层7距离第一电极1的距离不同，可以参见前述一种显示基板中的描述。
(4)在金属反射层7上形成第二电子传输层42，如图17D所示，第二电子传输层42和第一电子传输层41构成电子传输层4；第二电子传输层42的材料可以是ZnO或ZnMgO。
(5)在电子传输层4上分别沉积红绿蓝量子点发光层3，如图17E所示，量子点发光层3的材料及厚度参见前述一种显示基板中的描述。
(6)在量子点发光层3上形成空穴传输层6，如图17F所示，空穴传输层6的材料及厚度参见前述一种显示基板中的描述。
(7)在空穴传输层6上形成空穴注入层5，如图17G所示，空穴注入层5的材料及厚度参见前述一种显示基板中的描述。
(8)在空穴注入层5上形成第二电极2，如图17H所示，第二电极2的材料及厚度参见前述一种显示基板中的描述。
(9)在第二电极2上形成光取出层9，如图15所示，光取出层9的材料及厚度参见前述一种显示基板中的描述。
具体地，上述量子点发光器件中各膜层的制作方法包括但不限于旋涂法、蒸镀法、化学气相沉积法、物理气相沉积法、磁控溅射法、喷墨打印法、电喷印法等中的一种或多种。
需要说明的是，本公开实施例主要以倒置结构的量子点发光器件为例对 量子点发光器件的制作方法进行详细说明，正置结构的量子点发光器件的制作方法相比于倒置结构仅是膜层制作顺序发生变化，在此不做详述。
基于同一发明构思，本公开实施例还提供了一种显示装置，包括本公开实施例提供的上述显示基板。该显示装置可以为：手机、平板电脑、电视机、显示器、笔记本电脑、数码相框、导航仪等任何具有显示功能的产品或部件。对于该显示装置的其它必不可少的组成部分均为本领域的普通技术人员应该理解具有的，在此不做赘述，也不应作为对本发明的限制。由于该显示装置解决问题的原理与前述一种显示基板相似，因此该显示装置的实施可以参见前述显示基板的实施，重复之处不再赘述。
在具体实施时，本公开实施例提供的上述显示装置还可以包括本领域技术人员熟知的其他膜层，在此不做详述。
本公开实施例提供的上述显示基板、其制作方法及显示装置，通过在电子传输层的内部设置金属反射层，金属反射层可以调节器件的微腔长度，例如在保证器件电学平衡的情况下，将电流效率较大(电子传输层较厚)时对应的微腔长度(不适合光取出)调整为较合适的微腔长度(减小微腔长度，利于光取出)，通过金属反射层和第二电极之间的微腔调节器件出光，金属反射层和量子点发光层之间的电子传输层厚度可以较低，从而达到最优出光效率。同时，金属反射层与第一电极之间仍有电子传输层，此部分电子传输层可以用来调节器件的电学平衡，使得器件中电子传输层的厚度不至于过低，器件可以达到电学平衡。因此本公开实施例可以同时实现器件的出光效率最佳和电流效率最佳。
尽管已描述了本公开的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本公开范围的所有变更和修改。
显然，本领域的技术人员可以对本公开实施例进行各种改动和变型而不脱离本公开实施例的精神和范围。这样，倘若本公开实施例的这些修改和变型属于本公开权利要求及其等同技术的范围之内，则本公开也意图包含这些改动和变型在内。

Claims (26)

  1. 一种显示基板，其中，包括多个顶发射量子点发光器件，每一所述顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于所述第一电极和所述第二电极之间的量子点发光层，以及位于所述第一电极和所述量子点发光层之间的电子传输层；其中，
    所述电子传输层的内部具有金属反射层。
  2. 如权利要求1所述的显示基板，其中，每一所述顶发射量子点发光器中的所述金属反射层的面积与所述电子传输层的面积之比为50％～100％。
  3. 如权利要求1所述的显示基板，其中，所述金属反射层所在平面与所述电子传输层所在平面之间的夹角小于1‰度。
  4. 如权利要求1所述的显示基板，其中，所述多个顶发射量子点发光器件包括多个不同发光波长的顶发射量子点发光器件，各所述顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离与该所述顶发射量子点发光器件的发光波长呈反相关趋势。
  5. 如权利要求4所述的显示基板，其中，所述多个不同发光波长的顶发射量子点发光器件包括红色顶发射量子点发光器件、绿色顶发射量子点发光器件和蓝色顶发射量子点发光器件，所述红色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第一距离，所述绿色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第二距离，所述蓝色顶发射量子点发光器件中的金属反射层与所述第一电极之间的距离为第三距离；其中，所述第一距离为0～20nm，所述第二距离为20nm～40nm，所述第三距离为40nm～60nm。
  6. 如权利要求1-5任一项所述的显示基板，其中，所述金属反射层为面状结构。
  7. 如权利要求6所述的显示基板，其中，所述金属反射层的面积小于所述电子传输层的面积，且所述金属反射层位于所述电子传输层的中心区域。
  8. 如权利要求1-5任一项所述的显示基板，其中，所述金属反射层包括独立设置的多个镂空结构。
  9. 如权利要求8所述的显示基板，其中，所述多个镂空结构呈阵列分布。
  10. 如权利要求8所述的显示基板，其中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，所述多个镂空结构为沿所述第二方向延伸且沿所述第一方向排列的多个条状镂空结构，所述第一方向和所述第二方向交叉设置。
  11. 如权利要求9或10所述的显示基板，其中，各所述顶发射量子点发光器件中的相邻所述镂空结构之间的距离与该所述顶发射量子点发光器件的发光波长呈正相关趋势。
  12. 如权利要求1-5任一项所述的显示基板，其中，所述金属反射层包括独立设置的多个反射部以及位于相邻所述反射部之间的镂空结构。
  13. 如权利要求12所述的显示基板，其中，所述多个反射部呈阵列分布。
  14. 如权利要求12所述的显示基板，其中，还包括沿第一方向延伸且沿第二方向排列的多条数据线，所述多个反射部为沿所述第二方向延伸且沿所述第一方向排列的多个条状反射部，所述第一方向和所述第二方向交叉设置。
  15. 如权利要求13或14所述的显示基板，其中，各所述顶发射量子点发光器件中的相邻所述反射部之间的距离与该所述顶发射量子点发光器件的发光波长呈正相关趋势。
  16. 如权利要求1-15任一项所述的显示基板，其中，所述金属反射层在可见光范围内的反射率为30％～60％。
  17. 如权利要求1-15任一项所述的显示基板，其中，所述金属反射层的功函数为2.2eV～4.2eV，所述金属反射层的厚度为3nm～5nm。
  18. 如权利要求1-15任一项所述的显示基板，其中，所述金属反射层的材料包括Mg、Ag、Al。
  19. 如权利要求1-18任一项所述的显示基板，其中，所述电子传输层的材料包括金属氧化物纳米粒子，所述金属反射层背离所述第一电极的表面凹 凸不平。
  20. 如权利要求19所述的显示基板，其中，所述电子传输层与所述第一电极接触的表面的氧空位比例小于所述电子传输层与所述金属反射层接触的表面的氧空位比例。
  21. 如权利要求1-20任一项所述的显示基板，其中，所述电子传输层的厚度为50nm～80nm。
  22. 如权利要求1-21任一项所述的显示基板，其中，还包括：位于所述量子点发光层和所述第二电极之间的空穴传输层，以及位于所述空穴传输层和所述第二电极之间的空穴注入层。
  23. 如权利要求22所述的显示基板，其中，所述空穴传输层的厚度为10nm～40nm，所述空穴注入层的厚度为3nm～7nm，所述量子点发光层的厚度为10nm～40nm。
  24. 一种显示装置，其中，包括如权利要求1-23任一项所述的显示基板。
  25. 一种用于制作如权利要求1-23任一项所述的显示基板的制作方法，其中，包括：
    制作多个顶发射量子点发光器件；其中，每一所述顶发射量子点发光器件包括：相对设置的第一电极和第二电极，位于所述第一电极和所述第二电极之间的量子点发光层，以及位于所述第一电极和所述量子点发光层之间的电子传输层；所述电子传输层的内部具有金属反射层。
  26. 如权利要求25所述的制作方法，其中，制作所述电子传输层和所述金属反射层，具体为：
    形成第一电子传输层；
    在所述第一电子传输层上形成金属反射层；
    在所述金属反射层上形成第二电子传输层；所述第二电子传输层和所述第一电子传输层构成所述电子传输层。
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Citations (5)

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Publication number Priority date Publication date Assignee Title
CN201927638U (zh) * 2010-10-09 2011-08-10 中国计量学院 一种光栅结构有机发光二极管
CN104701431A (zh) * 2014-11-27 2015-06-10 厦门市三安光电科技有限公司 一种发光二极管的外延结构及其制作方法
CN111162192A (zh) * 2019-12-27 2020-05-15 山东大学 一种钙钛矿发光二极管
US20210050543A1 (en) * 2018-02-13 2021-02-18 Sharp Kabushiki Kaisha Light-emitting device
CN113871437A (zh) * 2021-09-18 2021-12-31 深圳大学 显示器件及其制备方法和显示装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201927638U (zh) * 2010-10-09 2011-08-10 中国计量学院 一种光栅结构有机发光二极管
CN104701431A (zh) * 2014-11-27 2015-06-10 厦门市三安光电科技有限公司 一种发光二极管的外延结构及其制作方法
US20210050543A1 (en) * 2018-02-13 2021-02-18 Sharp Kabushiki Kaisha Light-emitting device
CN111162192A (zh) * 2019-12-27 2020-05-15 山东大学 一种钙钛矿发光二极管
CN113871437A (zh) * 2021-09-18 2021-12-31 深圳大学 显示器件及其制备方法和显示装置

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