WO2023206681A1 - 显示面板 - Google Patents

显示面板 Download PDF

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Publication number
WO2023206681A1
WO2023206681A1 PCT/CN2022/095111 CN2022095111W WO2023206681A1 WO 2023206681 A1 WO2023206681 A1 WO 2023206681A1 CN 2022095111 W CN2022095111 W CN 2022095111W WO 2023206681 A1 WO2023206681 A1 WO 2023206681A1
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layer
light
emitting
sub
display panel
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PCT/CN2022/095111
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English (en)
French (fr)
Inventor
夏国奇
金武谦
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武汉华星光电半导体显示技术有限公司
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Publication of WO2023206681A1 publication Critical patent/WO2023206681A1/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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00

Definitions

  • the present application relates to the field of display technology, and in particular to a display panel.
  • OLED display panels have the characteristics of self-illumination, fast response, wide viewing angle, etc., and have very broad application prospects.
  • Embodiments of the present application provide a display panel for improving the service life of the display panel.
  • This application implementation provides a display panel, which includes:
  • a first electrode arranged on the substrate
  • a light-emitting functional layer is provided on a side of the first electrode away from the substrate.
  • the light-emitting functional layer includes a first light-emitting layer, a charge generation layer and a second light-emitting layer that are sequentially arranged on the first electrode, so
  • the first luminescent layer includes a first luminescent sub-layer
  • the second luminescent layer includes a second luminescent sub-layer;
  • a second electrode disposed on a side of the second light-emitting layer away from the charge generation layer
  • the first light-emitting sub-layer has a first film density parameter, the first film density parameter is greater than or equal to a first threshold, the second light-emitting sub-layer has a second film density parameter, and the first film density parameter is greater than or equal to a first threshold.
  • the second film density parameter is greater than or equal to the second threshold, and the first film density parameter and the second film density parameter are determined by the amount of deformation produced by the film under unit stress conditions.
  • the first film density parameter and the second film density parameter are generated from the stressed part of the film under unit stress conditions in the thickness direction of the film. Determined by the amount of thickness deformation.
  • the first film density parameter can be calculated by the following formula:
  • ⁇ F1 is the difference in different forces in the thickness direction of the film
  • ⁇ H1 is the difference in thickness of the stressed part of the film under different forces
  • the second film density parameter can be calculated by the following formula:
  • ⁇ F2 is the difference of different forces in the thickness direction of the film
  • ⁇ H2 is the thickness difference of the stressed part of the film under different forces.
  • the first threshold is -1.7, and the first film density parameter is less than 0;
  • the second threshold is -1.7, and the second film density parameter is less than 0.
  • the ratio between the size deformation amplitude of the light-emitting functional layer and the original shape and size of the light-emitting functional layer is less than or equal to 7.5 %.
  • the ratio between the thickness expansion of the light-emitting functional layer and the original thickness of the light-emitting functional layer is less than or equal to 7.5%.
  • the ratio between the size deformation amplitude of the light-emitting functional layer and the original shape and size of the light-emitting functional layer is less than or equal to 13 %.
  • the ratio between the thickness expansion of the light-emitting functional layer and the original thickness of the light-emitting functional layer is less than or equal to 13%.
  • the charge generation layer includes a first charge generation layer and a second charge generation layer, and the first charge generation layer is disposed away from the first light-emitting layer.
  • the first charge generation layer includes an n-type charge generation material
  • the second charge generation layer is disposed on a side of the first charge generation layer away from the first light-emitting layer.
  • the second charge generation layer includes a p-type charge generation material.
  • the first light-emitting layer includes a first hole injection sub-layer, a first hole transport sub-layer, the first light-emitting sub-layer, and a first hole transport sub-layer, which are stacked in sequence. an electron transport sublayer and a first electron injection sublayer;
  • the second light-emitting layer includes a second hole injection sub-layer, a second hole transport sub-layer, the second light-emitting sub-layer, a second electron transport sub-layer and a second electron injection sub-layer which are stacked in sequence.
  • the sum of the energy levels of the highest occupied orbitals of the first hole transport sublayer, the first light emitting sublayer and the first electron transport sublayer is The energy level of the lowest unoccupied orbital decreases in sequence, and the energy level of the highest occupied orbital and the lowest unoccupied orbital of the second hole transport sublayer, the second light emitting sublayer and the second electron transport sublayer The energy levels decrease in sequence.
  • the energy level difference between the highest occupied orbits of the first hole transport sublayer and the first light emitting sublayer is less than or equal to 0.2eV, and the first electron transport sublayer The energy level difference between the sublayer and the lowest empty orbit of the first light-emitting sublayer is less than or equal to 0.2eV;
  • the energy level difference between the highest occupied orbits of the second hole transport sublayer and the second light emitting sublayer is less than or equal to 0.2eV, and the lowest empty orbital of the second electron transport sublayer and the second light emitting sublayer is The energy level difference is less than or equal to 0.2eV.
  • the first luminescent sub-layer comprises a blue phosphorescent luminescent material or a blue fluorescent luminescent material
  • the second luminescent sub-layer comprises a blue phosphorescent luminescent material or a blue luminescent material. Fluorescent luminescent materials.
  • the first luminescent sub-layer and the second luminescent sub-layer include red phosphorescent luminescent material or red fluorescent luminescent material.
  • the first luminescent sub-layer and the second luminescent sub-layer include green phosphorescent luminescent material or green fluorescent luminescent material.
  • the first electrode is an anode
  • the second electrode is a cathode
  • This application also provides a display panel, which includes:
  • a first electrode arranged on the substrate
  • a light-emitting functional layer is provided on a side of the first electrode away from the substrate.
  • the light-emitting functional layer includes a first light-emitting layer, a charge generation layer and a second light-emitting layer that are sequentially arranged on the first electrode, so
  • the first luminescent layer includes a first luminescent sub-layer
  • the second luminescent layer includes a second luminescent sub-layer;
  • a second electrode disposed on a side of the second light-emitting layer away from the charge generation layer
  • the first light-emitting sub-layer has a first film density parameter, the first film density parameter is greater than or equal to a first threshold, the second light-emitting sub-layer has a second film density parameter, and the first film density parameter is greater than or equal to a first threshold.
  • the two film density parameters are greater than or equal to the second threshold, and the first film density parameter and the second film density parameter are determined by the amount of deformation produced by the film under unit stress conditions, wherein the film density parameter Characterization by atomic force microscopy.
  • the first film density parameter and the second film density parameter are generated from the stressed part of the film under unit stress conditions in the thickness direction of the film. Determined by the amount of thickness deformation.
  • the first film density parameter can be calculated by the following formula:
  • ⁇ F1 is the difference in different forces in the thickness direction of the film
  • ⁇ H1 is the difference in thickness of the stressed part of the film under different forces
  • the second film density parameter can be calculated by the following formula:
  • ⁇ F2 is the difference of different forces in the thickness direction of the film
  • ⁇ H2 is the thickness difference of the stressed part of the film under different forces.
  • the second threshold is -1.7, and the second film density parameter is less than 0.
  • Embodiments of the present application provide a display panel, which includes a substrate, a first electrode, a light-emitting functional layer, and a second electrode.
  • the first electrode is arranged on the substrate.
  • the light-emitting functional layer is disposed on a side of the first electrode away from the substrate.
  • the light-emitting functional layer includes a first light-emitting layer, a charge generation layer and a second light-emitting layer sequentially arranged on the first electrode.
  • the first luminescent layer includes a first luminescent sub-layer.
  • the second luminescent layer includes a second luminescent sub-layer.
  • the second electrode is disposed on a side of the second light-emitting layer away from the charge generation layer.
  • the first light-emitting sub-layer has a first film density parameter, and the first film density parameter is greater than or equal to the first threshold.
  • the second light-emitting sub-layer has a second film density parameter, and the second film density parameter is greater than or equal to the second threshold.
  • the first film density parameter and the second film density parameter are determined by the amount of deformation produced by the film under unit stress conditions.
  • the inventor of the present application found that when the first film density parameter of the first light-emitting sublayer is greater than or equal to the first threshold, and the second film density parameter of the second light-emitting sublayer is greater than or equal to the second threshold, the film density The parameter is positively related to the life of the display panel.
  • the greater the film density parameter the greater the density of the film and the longer the life of the display panel.
  • heat will be generated during operation. The heat will cause the film thickness of the display panel to expand, resulting in changes in the length of the microcavity of the display panel.
  • Figure 1 is a schematic structural diagram of a display panel provided by an embodiment of the present application.
  • Figure 2 is a schematic diagram of using an atomic force microscope to characterize the film density parameters of the first light-emitting sublayer in this embodiment
  • Figure 3 is a linear relationship fitted by using mCP as the host material of the first light-emitting sublayer provided by the embodiment of the present application;
  • Figure 4 is the chemical structural formula of the organic light-emitting material provided by the embodiment of the present application.
  • FIG. 5 is an energy level arrangement diagram of a display panel provided by an embodiment of the present application.
  • 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.
  • features defined as “first” and “second” may explicitly or implicitly include one or more of the described features.
  • “plurality” means two or more than two, unless otherwise explicitly and specifically limited.
  • An embodiment of the present application provides a display panel. Each is explained in detail below. It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments.
  • FIG. 1 is a schematic structural diagram of a display panel according to an embodiment of the present application.
  • the display panel 100 includes a substrate 101, a first electrode 102, a light-emitting functional layer 10 and a second electrode 106.
  • the first electrode 102 is provided on the substrate 101.
  • the light-emitting functional layer 10 is disposed on the side of the first electrode 102 away from the substrate 101.
  • the light-emitting functional layer 10 includes a first light-emitting layer 103, a charge generation layer 104 and a second light-emitting layer 105 which are sequentially arranged on the first electrode 102.
  • the first light-emitting layer 103 includes a first light-emitting sub-layer 1033.
  • the second light-emitting layer 105 includes a second light-emitting sub-layer 1053.
  • the second electrode 106 is disposed on a side of the second light-emitting layer 105 away from the charge generation layer 104 .
  • the first light-emitting sublayer 1033 has a first film density parameter, and the first film density parameter is greater than or equal to the first threshold.
  • the second light-emitting sublayer 1053 has a second film density parameter, and the second film density parameter is greater than or equal to the second threshold.
  • the first film density parameter and the second film density parameter are determined by the amount of deformation produced by the film under unit stress conditions.
  • the inventor of the present application found that when the first film density parameter of the first light-emitting sub-layer 1033 is greater than or equal to the first threshold, and when the second film density parameter of the second light-emitting sub-layer 1053 is greater than or equal to the second threshold, The film density parameter is positively related to the life of the display panel 100. The greater the film density parameter, the greater the film density, and the longer the life of the display panel 100.
  • the display panel 100 with a stacked structure formed by multiple light-emitting units connected in series will generate heat during operation, the heat will cause the thickness of the film layer of the display panel 100 to expand, causing the length of the microcavity of the display panel 100 to change, and the change in the length of the microcavity will cause This causes the device's luminous color to shift, resulting in uneven display of the display device.
  • the applicant of this application found that when the first film density parameter of the first light-emitting sub-layer 1033 is greater than or equal to the first threshold, and when the second film density parameter of the second light-emitting sub-layer 1053 is greater than or equal to the second threshold, The phenomenon of thermally induced light color shift caused by heat generated by the display panel 100 formed by multiple light-emitting units connected in series can be effectively improved.
  • the first film density parameter is related to the film density of the first light-emitting sublayer 1033.
  • the higher the film density the greater the first film density parameter.
  • the second film density parameter is related to the film density of the second light-emitting sublayer 1053. The higher the film density, the greater the second film density parameter.
  • the greater the first film density parameter when the first film density parameter of the first light-emitting sub-layer 1033 is greater than or equal to the first threshold, the greater the first film density parameter, the greater the film density of the first light-emitting sub-layer 1033 . big.
  • the second film density parameter of the second light-emitting sub-layer 1053 is greater than or equal to the second threshold, the greater the second film density parameter, the greater the film density of the second light-emitting sub-layer 1053, which effectively improves the improvement by
  • the display panel 100 formed by the light-emitting units connected in series causes a thermally induced light color shift, thereby improving the uneven display of the display panel 100 .
  • the unit force includes but is not limited to the force exerted on the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053.
  • the unit force here refers to the smallest unit force exerted on the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053 for measurement, such as 1N, 2N, 5N, 10N, etc.
  • the amount of deformation produced by the film includes but is not limited to the amount of deformation of the thickness of the film.
  • the first film density parameter and the second film density parameter are determined by the thickness deformation amount produced by the stressed part of the film under unit stress conditions in the thickness direction of the film.
  • the first film density parameter can be calculated by the following formula: The thickness difference of the stressed part of the film under different forces, 0>X1 ⁇ -1.7N/cm.
  • the first threshold is -1.7N/cm.
  • the second film density parameter can be calculated by the following formula: The thickness difference of the force part under different forces, 0>X2 ⁇ -1.7N/cm.
  • the second threshold is -1.7N/cm.
  • ⁇ F1 or ⁇ F2 can be the difference between two different forces applied to the same force-bearing part, and ⁇ H1 or ⁇ H2 is the difference in thickness corresponding to the two different forces.
  • ⁇ F1 or ⁇ F2 is the difference between the forces applied to two different force-bearing parts, and ⁇ H1 or ⁇ H2 is the difference in thickness corresponding to the two different forces.
  • an atomic force microscope can be used to characterize the first film density parameter of the first light-emitting sub-layer 1033 and the second film density parameter of the second light-emitting sub-layer 1053.
  • an atomic force microscope there is a linear relationship between the thickness of the first light-emitting sublayer 1033 and the force of the probe of the atomic force microscope on the first light-emitting sublayer 1033.
  • the slope of the linear relationship is the second film density parameter.
  • the slope of the linear relationship is the second film density parameter.
  • an atomic force microscope is used to characterize the first luminescent sub-layer 1033 and the second luminescent sub-layer 1053, and then, the thickness of the first luminescent sub-layer 1033 and the effect of the first luminescent sub-layer 1033 on the probe of the atomic force microscope are established.
  • the greater the density of the films of the layer 1033 and the second light-emitting sub-layer 1053 the more conducive to improving the thermochromic shift phenomenon of the display panel 100 .
  • FIG. 2 is a schematic diagram of using an atomic force microscope to characterize the density parameters of the first film of the first light-emitting sublayer in this embodiment.
  • Evaluating the film density parameters of the first light-emitting sub-layer 1033 specifically includes characterizing the light-emitting sub-layer 1033 using an atomic force microscope.
  • the process of characterizing the first luminescent sub-layer 1033 with an atomic force microscope may include disposing the first luminescent sub-layer 1033 on the substrate S, and then using the probe P to detect the relative thickness of the first luminescent sub-layer 1033.
  • disposing the first light-emitting sub-layer 1033 on the substrate S includes disposing a polyimide layer PI on the substrate S, and the polyimide layer PI covers a part of the substrate S.
  • the luminescent sub-layer 1033 is evaporated on the substrate S.
  • the first luminescent sub-layer 1033 covers the polyimide layer PI and the substrate S, and then the polyimide layer PI is peeled off, so as to obtain a film on the substrate S.
  • the first light-emitting sub-layer 1033 only covers a part of the substrate S, thereby forming a height difference, which is used to measure the relative thickness of the first light-emitting sub-layer 1033.
  • the steps of using the probe P to detect the relative thickness of the first light-emitting sub-layer 1033 include: first, randomly selecting any point on the first light-emitting sub-layer 1033, the probe P applying a first force to it, and then using the first The force probe P is applied to the substrate S, and the first relative thickness of the first light-emitting sub-layer 1033 is measured.
  • the probe P applies a second force to it, and then the second force is applied to the substrate S by the probe P, and the value of the first light-emitting sub-layer 1033 is measured.
  • Second relative thickness By repeating this, the third relative thickness of the first light-emitting sub-layer 1033 is measured using the third acting force, and the fourth relative thickness of the light-emitting layer is measured using the fourth acting force.
  • the Nth relative thickness of the first light-emitting sublayer 1033 is measured using the Nth force.
  • the slope of the fitted linear relationship is used as the third value of the first light-emitting sublayer 1033.
  • a film density parameter The greater the slope, the greater the film density of the first light-emitting sublayer 1033, which is more conducive to improving the thermochromic shift phenomenon of the display panel 100.
  • the thickness of the first light-emitting sub-layer 1033 decreases as the force of the probe P on the first light-emitting sub-layer 1033 increases.
  • the force of the probe P received by the first light-emitting sub-layer 1033 is is the abscissa, and the thickness of the first light-emitting sublayer 1033 is the ordinate, and the corresponding linear relationship is obtained by fitting.
  • Figure 3 is a linear relationship fitted by the light-emitting host material using mCP (N,N-dicarbazolyl-3,5-benzene) as the first light-emitting sublayer provided by the embodiment of the present application.
  • mCP N,N-dicarbazolyl-3,5-benzene
  • the fitted linear relationship The slope of is used as the first film density parameter of the first light-emitting sub-layer 1033, where the slope is -1.69.
  • the embodiment of the present application uses 10 different organic luminescent materials as the host materials of the first luminescent sub-layer 1033 and the second luminescent sub-layer 1053 to evaluate the properties of the first luminescent sub-layer 1033 and the second luminescent sub-layer 1053.
  • Film density and luminescence properties please refer to Figure 4.
  • Figure 4 is a chemical structural formula of an organic light-emitting material provided in an embodiment of the present application.
  • Organic light-emitting materials include DCB, CBP, CDBP, CBPE, mCP, BCzph, CzC, 4CzPBP, TPBi, BCzTPM, BCPPA, NPB, TAPC and Firpic.
  • Table 1 shows the performance test results of display panels using 10 different organic light-emitting materials as host materials.
  • the slope is measured by using the above-mentioned atomic force microscope to act on the thin films of the first light-emitting sublayer 1033 and the second light-emitting sublayer 1053.
  • the first threshold can also be selected from -1.65, -1.6, -1.55, -1.5, -1.45, -1.4, -1.35, -1.3, -1.25, -1.2, -1.15, etc.
  • the second threshold can also be selected from -1.65, -1.6, -1.55, -1.5, -1.45, -1.4, -1.35, -1.3, -1.25, -1.2, -1.15, etc.
  • the lifespan of blue phosphorescent materials is particularly short, resulting in a reduction in the overall lifespan and reliability of the display panel 100 .
  • taking blue phosphorescent material as an example by increasing the film density of the blue phosphorescent material, the thermochromic shift amplitude is reduced, and the life span and life of the display panel 100 of the blue phosphorescent material are improved. reliability, thereby improving market competitiveness.
  • the first luminescent sub-layer 1033 includes, but is not limited to, blue phosphorescent luminescent material or blue fluorescent luminescent material.
  • the first luminescent sub-layer 1033 may also be red phosphorescent luminescent material and green phosphorescent luminescent material, red fluorescent luminescent material and green fluorescent luminescent material.
  • the second luminescent sub-layer 1053 includes, but is not limited to, blue phosphorescent luminescent material or blue fluorescent luminescent material.
  • the second luminescent sub-layer 1053 may also be red phosphorescent luminescent material and green phosphorescent luminescent material, red fluorescent luminescent material and green fluorescent luminescent material.
  • an atomic force microscope is used to characterize the first luminescent sub-layer 1033 and the second luminescent sub-layer 1053, and the thickness of the first luminescent sub-layer 1033 and the probe of the atomic force microscope subjected to the first luminescent sub-layer 1033 are established.
  • the greater the slope of the linear relationship the greater the linear relationship.
  • the slope of is the film density parameter of the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053.
  • the greater the density parameter of the film the greater the density of the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053.
  • the first film density parameter is greater than or equal to the first threshold
  • the second film density parameter is greater than or equal to the second threshold
  • the film-forming quality of the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053 can also be evaluated by measuring the dimensional deformation amplitude of the display panel 100 .
  • the size change range of the light-emitting functional layer 10 is the difference between the original shape and size of the light-emitting functional layer 10. The ratio between them is less than or equal to 7.5%.
  • the dimensional change range of the light-emitting functional layer 10 includes but is not limited to the thickness expansion range of the light-emitting functional layer 10 .
  • the ratio between the thickness expansion of the light-emitting functional layer 10 and the original thickness of the light-emitting functional layer 10 is less than or equal to 7.5%.
  • the light-emitting functional layer 10 has a first thickness a before being powered on, and after the light-emitting functional layer 10 lights up at a preset brightness for a preset working time, the light-emitting functional layer 10 has a second thickness b.
  • the preset brightness may be 100 nits, and the preset time may be 1 hour.
  • an interferometer is used to measure the thickness before and after lighting.
  • the thickness of the light-emitting functional layer 10 before and after being heated can also be evaluated by heating the display panel 100 .
  • the ratio between the size deformation amplitude of the light-emitting functional layer 10 and the original shape and size of the light-emitting functional layer 10 is less than or equal to 13%.
  • the ratio between the thickness expansion of the light-emitting functional layer 10 and the original thickness of the light-emitting functional layer 10 is less than or equal to 13%.
  • the luminescent functional layer 10 before heating has a first thickness a
  • the luminescent functional layer 10 after the luminescent functional layer 10 is heated at a preset temperature for a preset working time, the luminescent functional layer 10 has a second thickness c; where the second thickness c and the The thickness expansion amplitude ⁇ 2 of a thickness a is less than or equal to 13%.
  • ⁇ 2 [(c-a)/a]*100%.
  • the preset temperature can be 100 degrees Celsius, and the preset working time can be 1 hour. Specifically, the luminescent functional layer 10 is heated to 100 degrees Celsius, maintained at 100 degrees Celsius for 1 hour, and the thickness of the heated luminescent functional layer 10 is measured using an interferometer.
  • Table 2 shows the thickness expansion range of the light-emitting functional layer 10 when the display panel 100 is powered on and heated.
  • the thickness of the light-emitting functional layer 10 of the display panel 100 before and after heating is measured by an interferometer, and the thickness expansion amplitude of the light-emitting functional layer 10 before and after heating is obtained.
  • the thickness of the light-emitting functional layer 10 after heating The smaller the expansion.
  • the maximum value of ⁇ 1 can be selected as 7.5%, 7%, 6.5%, 6%, 5.5%, 5%, 4.5%, etc.; the maximum value of ⁇ 2 can be selected as 13%, 12.5 %, 12%, 11.5%, 11%, 10.5%, 10%, 9.5%, 9%, etc.
  • the film formation quality of the light-emitting functional layer 10 of the display panel 100 is evaluated from two dimensions. This includes evaluating the density of the first light-emitting sub-layer 1033 and the second light-emitting sub-layer 1053, and evaluating the thickness of the display panel 100 as a whole of the light-emitting functional layer 10 of the display panel 100 before and after being heated. Evaluating the film-forming quality of the display panel 100 in two dimensions shows that under the characterization of an atomic force microscope, the greater the slope, the greater the film density parameter of the light-emitting sublayer, and the greater the density of the light-emitting sublayer.
  • the density of the light-emitting sublayer increases, the impact on voltage and electroluminescence peak (EL Peak) is small, the external quantum efficiency (EQE) is slightly improved, and the lifetime improvement is very significant. It is proved that the higher the density of the luminescent sublayer, the more beneficial it is to the luminescent performance of the blue phosphorescent material.
  • thermochromic shift amplitude the more uniform the display, and the longer the life of the display panel 100 .
  • the charge generation layer 104 includes a first charge generation layer 1041 and a second charge generation layer 1042 .
  • the first charge generation layer 1041 is provided on a side of the first light-emitting layer 103 away from the first electrode 102
  • the second charge generation layer 1042 is provided on a side of the first charge generation layer 1041 away from the first light-emitting layer 103 .
  • the first charge generation layer 1041 is an n-type charge generation layer, and the material of the first charge generation layer 1041 includes an n-type charge generation material.
  • the second charge generation layer 1042 is a p-type charge generation layer, and the material of the second charge generation layer 1042 includes a p-type charge generation material.
  • a carrier injected from the electrode can flow through two independent light-emitting units in sequence, and the luminous efficiency is significantly improved.
  • the first light-emitting layer 103 further includes a first hole injection sub-layer 1031, a first hole transport sub-layer 1032, a first electron transport sub-layer 1034 and a first electron injection sub-layer 1035.
  • the first hole injection sub-layer 1031 and the first hole transport sub-layer 1032 are arranged on the first electrode 102 in sequence.
  • the first light emitting sub-layer 1033 is disposed on the first hole transport sub-layer 1032.
  • the first electron transport sub-layer 1034 and the first electron injection sub-layer 1035 are disposed on the first light-emitting sub-layer 1033 in sequence.
  • the first charge generation layer 1041 and the second charge generation layer 1042 are sequentially disposed on the first electron injection sub-layer 1035.
  • the second light-emitting layer 105 further includes a second hole injection sub-layer 1051, a second hole transport sub-layer 1052, a second electron transport sub-layer 1054 and a second electron injection sub-layer 1055.
  • the second hole injection sub-layer 1051 and the second hole transport sub-layer 1052 are sequentially disposed on the second charge generation layer 1042.
  • the second electron transport sub-layer 1054 and the second electron injection sub-layer 1055 are sequentially disposed on the side of the second light-emitting sub-layer 1053 away from the second hole transport sub-layer 1052.
  • FIG. 5 is an energy level arrangement diagram of a display panel provided by an embodiment of the present application.
  • the lowest unoccupied orbital energy level and the highest occupied orbital energy level of the first hole transport sublayer 1032, the first light emitting sublayer 1033 and the first electron transport sublayer 1034 decrease in sequence.
  • the first light emitting sublayer 1033 and the first electron transport sublayer 1034 decrease in sequence, that is, each phase
  • the highest occupied orbital (The Highest Occupied Molecular Orbitals) energy level and the lowest unoccupied orbital (The Lowest Unoccupied Molecular Orbitals) energy level of the adjacent organic film layer material are arranged in a stepped manner. This arrangement is conducive to the balanced injection and transmission of carriers. , lowering the energy level barrier, thereby improving the luminous efficiency of the display panel 100, and thereby obtaining optimal device performance.
  • the highest occupied orbit refers to the molecular orbital with the highest energy among the molecular orbitals occupied by electrons. It is called the highest occupied orbital, also called the highest occupied molecular orbital. Among the molecular orbitals that are not occupied by electrons, the molecular orbital with the lowest energy is called the lowest unoccupied orbital.
  • electrons and holes can be injected in a balanced ratio of 1:1 to achieve efficient utilization of electrons and holes.
  • holes can be effectively injected from the first electrode 102 into the display panel 100.
  • the transport rate of holes is generally greater than the transport rate of electrons.
  • the first hole transport sub-layer 1032 and the first light-emitting sub-layer 1033 The energy level structure matches and the hole migration velocity matches.
  • electrons can be efficiently injected from the second electrode 106 into the display panel 100.
  • the lowest empty orbits of the first hole injection sub-layer 1031, the first hole transport sub-layer 1032, the first light-emitting sub-layer 1033, the first electron transport sub-layer 1034 and the first electron injection sub-layer 1035 The energy level and the highest occupied orbital energy level decrease successively. Such an arrangement is conducive to the balanced injection and transmission of carriers and reduces the energy level barrier, thereby further improving the luminous efficiency of the display panel 100 and obtaining optimal device performance.
  • the energy level difference between the highest occupied orbitals of the first hole transport sublayer 1032 and the first light emitting sublayer 1033 is less than or equal to 0.2 eV, and the lowest energy level difference between the first electron transport sublayer 1034 and the first light emitting sublayer 1033 is less than or equal to 0.2 eV.
  • the energy level difference of empty orbitals is less than or equal to 0.2eV.
  • the energy level difference between the highest occupied orbitals of the first hole transport sublayer 1032 and the first light emitting sublayer 1033 may be any one of 0.05eV, 0.08eV, 0.12eV, 0.15eV, 0.18eV or 0.2eV.
  • the energy level difference between the lowest empty orbits of the first hole transport sublayer 1032 and the first light emitting sublayer 1033 may be any one of 0.05eV, 0.08eV, 0.12eV, 0.15eV, 0.18eV or 0.2eV.
  • the lowest unoccupied orbital energy level and the highest occupied orbital energy level of the second hole transport sublayer 1052, the second light emitting sublayer 1053 and the second electron transport sublayer 1054 decrease in sequence.
  • the second light emitting sublayer 1053 and the second electron transport sublayer 1054 decrease sequentially, that is, each phase
  • the highest occupied orbital (The Highest Occupied Molecular Orbitals) energy level and the lowest unoccupied orbital (The Lowest Unoccupied Molecular Orbitals) energy level of the adjacent organic film layer material are arranged in a stepped manner. This arrangement is conducive to the balanced injection and transmission of carriers. , lowering the energy level barrier, thereby improving the luminous efficiency of the display panel 100, and thereby obtaining optimal device performance.
  • electrons and holes can be injected in a balanced ratio of 1:1 to achieve efficient utilization of electrons and holes.
  • holes can be effectively injected from the first electrode 102 into the display panel 100.
  • the transport rate of holes is generally greater than the transport rate of electrons.
  • the second hole transport sublayer 1052 and the second light-emitting sublayer 1053 The energy level structure matches and the hole migration velocity matches.
  • electrons can be efficiently injected from the second electrode 106 into the display panel 100.
  • the material of the second electron injection sub-layer 1055 in order to enable electrons to be effectively injected from the second electrode 106 into the display panel 100.
  • Lowering the barrier for hole injection from the anode allows holes to be efficiently injected from the anode into the OLED device. Therefore, when selecting the electron injection layer material, it is necessary to consider the matching of the material energy level and the material of the second electrode 106 .
  • the lowest empty orbits of the second hole injection sub-layer 1051, the second hole transport sub-layer 1052, the second light-emitting sub-layer 1053, the second electron transport sub-layer 1054 and the second electron injection sub-layer 1055 The energy level and the highest occupied orbital energy level decrease successively. Such an arrangement is conducive to the balanced injection and transmission of carriers and reduces the energy level barrier, thereby further improving the luminous efficiency of the display panel 100 and obtaining optimal device performance.
  • the energy level difference between the highest occupied orbitals of the second hole transport sublayer 1052 and the second light emitting sublayer 1053 is less than or equal to 0.2 eV, and the lowest energy level difference between the second electron transport sublayer 1054 and the second light emitting sublayer 1053 is less than or equal to 0.2 eV.
  • the energy level difference of empty orbitals is less than or equal to 0.2eV.
  • the energy level difference between the highest occupied orbitals of the second hole transport sublayer 1052 and the second light emitting sublayer 1053 may be any one of 0.05eV, 0.08eV, 0.12eV, 0.15eV, 0.18eV or 0.2eV.
  • the energy level difference between the lowest empty orbitals of the second hole transport sublayer 1052 and the second light emitting sublayer 1053 may be any one of 0.05eV, 0.08eV, 0.12eV, 0.15eV, 0.18eV or 0.2eV.
  • the display panel 100 further includes a thin film transistor structural layer disposed on the substrate 101 , and the thin film transistor structural layer is used to drive the display panel 100 to emit light.
  • the first electrode 102 is an anode, and the material of the first electrode 102 is a laminate material of indium tin oxide, silver and indium tin oxide.
  • the second electrode 106 is a cathode, and the material of the second electrode 106 is a magnesium and silver alloy material.
  • inventions of the present application also provide a method for manufacturing a display panel.
  • the method for manufacturing the display panel 100 includes the following steps:
  • Step B001 Provide a substrate.
  • Step B002 Form a first electrode on the substrate, where the first electrode is a stacked material of indium tin oxide, silver and indium tin oxide.
  • Step B003 Form a first light-emitting layer on the first electrode.
  • the first light-emitting layer includes a first hole injection sub-layer, a first hole transport sub-layer, a first light-emitting sub-layer, a first electron transport sub-layer and a first electron injection sub-layer which are stacked in sequence.
  • the material of the first hole transport sublayer can be NPB (N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4-4′- diamine) with a thickness ranging from 10 nm to 60 nm. In a specific embodiment, the thickness of the first hole transport sub-layer may be 20 nanometers.
  • the first light-emitting sublayer is an organic light-emitting material, and the concentration of the doped organic light-emitting material is less than 2%.
  • the evaporation rate of the light-emitting sublayer is less than or equal to 1.5 angstroms/second. In one embodiment, the evaporation rate of the first light-emitting sub-layer is 1.0 angstroms/second.
  • the host material of the organic light-emitting material may be at least one of DCB, CBP, CDBP, CBPE, mCP, BCzph, CzC, 4CzPBP, TPBi, BCzTPM, BCPPA, NPB, TAPC, and Irpic.
  • the thickness of the first light emitting sub-layer may range from 10 nanometers to 30 nanometers. In a specific embodiment, the thickness of the first light-emitting sub-layer may be 20 nanometers.
  • the step of forming the first light-emitting layer on the first electrode includes forming a first electron blocking layer on the first hole transport sublayer, and the material of the first electron blocking layer may be TAPC (4,4' -Cyclohexylbis[N,N-bis(4-methylphenyl)aniline]).
  • the thickness of the first electron blocking layer may range from 2 nanometers to 10 nanometers. In a specific embodiment, the thickness of the first electron blocking layer may be 5 nanometers.
  • Step B004 Form a charge generation layer on the first light-emitting layer.
  • the charge generation layer includes a first charge generation layer and a second charge generation layer.
  • the first charge generation layer is an n-type charge generation layer
  • the second charge generation layer is a p-type charge generation layer.
  • the first charge generation layer includes an n-type charge generation material, such as TPBi doped with 5% Yb and has a thickness of 100 nm
  • the second charge generation layer includes a p-type charge generation material, such as NPB doped with 5% HATCN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene), its thickness is 100nm.
  • Step B004 Form a second light-emitting layer on the charge generation layer, wherein the second light-emitting layer includes a second hole injection sub-layer, a second hole transport sub-layer, a second light-emitting sub-layer, and a second electron layer that are stacked in sequence.
  • Transport sublayer and second electron injection sublayer can be NPB (N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4-4′- diamine) with a thickness ranging from 10 nm to 60 nm. In a specific embodiment, the thickness of the second hole transport sub-layer may be 20 nanometers.
  • the third light-emitting sub-layer is an organic light-emitting material, and the concentration of the doped organic light-emitting material is less than 2%.
  • the evaporation rate of the light-emitting sublayer is less than or equal to 1.5 angstroms/second. In one embodiment, the evaporation rate of the second light-emitting sublayer is 1.0 angstroms/second.
  • the host material of the organic light-emitting material may be at least one of DCB, CBP, CDBP, CBPE, mCP, BCzph, CzC, 4CzPBP, TPBi, BCzTPM, BCPPA, NPB, TAPC, and Firpic.
  • the thickness of the second light emitting sub-layer may range from 10 nanometers to 30 nanometers. In a specific embodiment, the thickness of the second light-emitting sublayer may be 20 nanometers.
  • the second hole transport sublayer is NPB and has a thickness of 20 nm.
  • the material of the second electron transport sublayer is TPBi, and its thickness is 35nm.
  • the second electron is injected into the sub-layer Yb (ytterbium) and has a thickness of 1 nm.
  • the step of forming the second light-emitting layer on the charge generation layer includes forming a second electron blocking layer on the second hole transport sub-layer.
  • the material of the second electron blocking layer may be TAPC(4,4' -Cyclohexylbis[N,N-bis(4-methylphenyl)aniline]).
  • the thickness of the second electron blocking layer may range from 2 nanometers to 10 nanometers. In a specific embodiment, the thickness of the second electron blocking layer may be 5 nanometers.
  • Step B005 evaporate a second electrode on the side of the second light-emitting layer that can be away from the charge generation layer.
  • the material of the second electrode may include silver and magnesium.
  • the evaporation rate of the second electrode is less than or equal to 3 angstroms/second. In one embodiment, the evaporation rate of the second electrode may be 2 angstroms/second.
  • the thickness of the second electrode is between 10 nanometers and 50 nanometers. For example, the thickness of the second electrode can be 13.2 nanometers.
  • the Mg doping concentration of the second electrode is 9%.

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Abstract

一种显示面板（100），显示面板（100）包括发光功能层（10）。发光功能层（10）包括第一发光层（103）和第二发光层（105）。第一发光层（103）包括第一发光子层（1033）。第二发光层（105）包括第二发光子层（1053）。第一发光子层（1033）具有第一薄膜致密性参数，第一薄膜致密性参数大于或等于第一阈值。第二发光子层（1053）具有第二薄膜致密性参数，第二薄膜致密性参数大于或等于第二阈值。第一薄膜致密性参数和第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定。

Description

显示面板 技术领域
本申请涉及显示技术领域，尤其涉及一种显示面板。
背景技术
有机发光二极管(Organic Light Emitting Diodes，OLED)显示面板具有自发光、快响应、广视角等特点，应用前景非常广阔。
在目前的商业应用中，单发光单元的单层OLED器件已经接近其性能极限，因此科学家通过电荷生成层连接多个发光单元，以获得较高的发光效率，和较长的器件寿命。叠层OLED器件的器件结构由电荷生成层连接第一发光单元和第二发光单元，由于电荷生成层的存在，由电极注入的一个载流子可依次流经两个独立的发光单元，发光效率有显著提高。
但是，在现有的OLED显示面板的结构设计策略中，更多考虑的是各个功能层的分子轨道能级排列形式，但是，优化能级排列形式更多的是优化OLED器件的效率，然而，效率并不是限制蓝色磷光OLED器件大规模商用的主要原因，是因为现有的蓝色磷光OLED器件的寿命普遍较短，才导致蓝色磷光OLED发光器件得不到广泛应用。
技术问题
本申请实施例提供一种显示面板，用于提高显示面板的使用寿命。
技术解决方案
本申请实施提供一种显示面板，其包括：
衬底，
第一电极，设置在所述衬底上；
发光功能层，设置在所述第一电极远离所述衬底的一面，所述发光功能层包括依次设置在所述第一电极上的第一发光层、电荷生成层和第二发光层，所述第一发光层包括第一发光子层，所述第二发光层包括第二发光子层；
第二电极，设置在所述第二发光层远离所述电荷生成层的一面；
其中，所述第一发光子层具有第一薄膜致密性参数，所述第一薄膜致密性 参数大于或等于第一阈值，所述第二发光子层具有第二薄膜致密性参数，所述第二薄膜致密性参数大于或等于第二阈值，所述第一薄膜致密性参数和所述第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定。
可选的，在本申请提供的一些实施例中，所述第一薄膜致密性参数和所述第二薄膜致密性参数由薄膜的厚度方向上，单位受力条件下，薄膜的受力部分产生的厚度形变量决定。
可选的，在本申请提供的一些实施例中，所述第一薄膜致密性参数可以由如下公式计算得到：
X1＝ΔF1/ΔH1；
其中，ΔF1为薄膜的厚度方向上的不同作用力的差值；ΔH1为薄膜的受力部分在不同作用力下的厚度差值；
所述第二薄膜致密性参数可以由如下公式计算得到：
X2＝ΔF2/ΔH2；
其中，ΔF2为薄膜的厚度方向上的不同作用力的差值；ΔH2为薄膜的受力部分在不同作用力下的厚度差值。
可选的，在本申请提供的一些实施例中，所述第一阈值为-1.7，所述第一薄膜致密性参数小于0；
所述第二阈值为-1.7，且所述第二薄膜致密性参数小于0。
可选的，在本申请提供的一些实施例中，所述显示面板通电工作状态下，所述发光功能层的尺寸形变幅度与所述发光功能层原有形状尺寸之间的比值小于或等于7.5％。
可选的，在本申请提供的一些实施例中，所述显示面板通电工作状态下，所述发光功能层的厚度膨胀幅度与所述发光功能层原有厚度之间的比值小于或等于7.5％。
可选的，在本申请提供的一些实施例中，所述显示面板在加热状态下，所述发光功能层的尺寸形变幅度与所述发光功能层原有形状尺寸之间的比值小于或等于13％。
可选的，在本申请提供的一些实施例中，所述显示面板在加热状态下，所 述发光功能层的厚度膨胀幅度与所述发光功能层原有厚度之间的比值小于或等于13％。
可选的，在本申请提供的一些实施例中，所述电荷生成层包括第一电荷生成层和第二电荷生成层，所述第一电荷生成层设置在所述第一发光层远离所述第一电极的一面，所述第一电荷生成层包括n-型电荷生成材料，所述第二电荷生成层设置在所述第一电荷生成层远离所述第一发光层的一面，所述第二电荷生成层包括p-型电荷生成材料。
可选的，在本申请提供的一些实施例中，所述第一发光层包括依次层叠设置的第一空穴注入子层、第一空穴传输子层、所述第一发光子层、第一电子传输子层和第一电子注入子层；
所述第二发光层包括依次层叠设置的第二空穴注入子层、第二空穴传输子层、所述第二发光子层、第二电子传输子层和第二电子注入子层。
可选的，在本申请提供的一些实施例中，所述第一所述空穴传输子层、所述第一发光子层和所述第一电子传输子层的最高占据轨道的能级和最低空轨道的能级依次减小，所述第二所述空穴传输子层、所述第二发光子层和所述第二电子传输子层的最高占据轨道的能级和最低空轨道的能级依次减小。
可选的，在本申请提供的一些实施例中，所述第一空穴传输子层和所述第一发光子层的最高占据轨道的能级差小于或等于0.2eV，所述第一电子传输子层和所述第一发光子层的最低空轨道的能级差小于等于0.2eV；
所述第二空穴传输子层和所述第二发光子层的最高占据轨道的能级差小于或等于0.2eV，所述第二电子传输子层和所述第二发光子层的最低空轨道的能级差小于等于0.2eV。13、根据权利要求1所述的显示面板，其中，所述第一发光子层包括蓝色磷光发光材料或蓝色荧光发光材料，所述第二发光子层包括蓝色磷光发光材料或蓝色荧光发光材料。
可选的，在本申请提供的一些实施例中，所述第一发光子层和所述第二发光子层包括红色磷光发光材料或红色荧光发光材料。
可选的，在本申请提供的一些实施例中，所述第一发光子层和所述第二发光子层包括绿色磷光发光材料或绿色荧光发光材料。
可选的，在本申请提供的一些实施例中，所述第一电极为阳极，所述第二电极为阴极。
本申请还提供一种显示面板，其包括：
衬底，
第一电极，设置在所述衬底上；
发光功能层，设置在所述第一电极远离所述衬底的一面，所述发光功能层包括依次设置在所述第一电极上的第一发光层、电荷生成层和第二发光层，所述第一发光层包括第一发光子层，所述第二发光层包括第二发光子层；
第二电极，设置在所述第二发光层远离所述电荷生成层的一面；
其中，所述第一发光子层具有第一薄膜致密性参数，所述第一薄膜致密性参数大于或等于第一阈值，所述第二发光子层具有第二薄膜致密性参数，所述第二薄膜致密性参数大于或等于第二阈值，所述第一薄膜致密性参数和所述第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定，其中，所述薄膜致密性参数通过原子力显微镜表征。
可选的，在本申请提供的一些实施例中，所述第一薄膜致密性参数和所述第二薄膜致密性参数由薄膜的厚度方向上，单位受力条件下，薄膜的受力部分产生的厚度形变量决定。
可选的，在本申请提供的一些实施例中，所述第一薄膜致密性参数可以由如下公式计算得到：
X1＝ΔF1/ΔH1；
其中，ΔF1为薄膜的厚度方向上的不同作用力的差值；ΔH1为薄膜的受力部分在不同作用力下的厚度差值；
所述第二薄膜致密性参数可以由如下公式计算得到：
X2＝ΔF2/ΔH2；
其中，ΔF2为薄膜的厚度方向上的不同作用力的差值；ΔH2为薄膜的受力部分在不同作用力下的厚度差值。
20、根据权利要求19所述的显示面板，其中，所述第一阈值为-1.7，所述第一薄膜致密性参数小于0；
所述第二阈值为-1.7，且所述第二薄膜致密性参数小于0。
有益效果
本申请实施例提供一种显示面板，显示面板包括衬底、第一电极、发光功能层和第二电极。其中，第一电极设置在衬底上。发光功能层设置在第一电极远离衬底的一面。发光功能层包括依次设置在第一电极上的第一发光层、电荷生成层和第二发光层。第一发光层包括第一发光子层。第二发光层包括第二发光子层。第二电极设置在第二发光层远离电荷生成层的一面。其中，第一发光子层具有第一薄膜致密性参数，第一薄膜致密性参数大于或等于第一阈值。第二发光子层具有第二薄膜致密性参数，第二薄膜致密性参数大于或等于第二阈值。第一薄膜致密性参数和第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定。
本申请的发明人发现，当第一发光子层的第一薄膜致密性参数大于或等于第一阈值，第二发光子层的第二薄膜致密性参数大于或等于第二阈值时，薄膜致密性参数和显示面板的寿命正相关，薄膜致密性参数越大，薄膜致密度越大，显示面板的寿命越长。另外，由于多个发光单元串联形成的叠层结构的显示面板在工作时，会产生热量，热量会导致显示面板的膜层厚度膨胀，导致显示面板微腔长度变化，微腔长度变化会导致器件的发光颜色偏移，导致显示器件显示不均。本申请的申请人发现，当第一发光子层的第一薄膜致密性参数大于或等于第一阈值，第二发光子层的第二薄膜致密性参数大于或等于第二阈值时，可以有效改善由多个发光单元串联形成的显示面板发热导致的热致光色偏移的现象。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述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申请的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请实施例提供的显示面板的一种结构示意图；
图2为本实施例利用原子力显微镜对第一发光子层的薄膜致密性参数进行表征的示意图；
图3为本申请实施例提供的以mCP为第一发光子层的主体材料拟合的线性关系；
图4为本申请实施例提供的有机发光材料的化学结构式；
图5为本申请实施例提供的显示面板的一种能级排布方式图。
具体实施方式
为了使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请作进一步地详细描述，请参照附图中的图式，其中相同的组件符号代表相同的组件，以下的说明是基于所示的本申请具体实施例，其不应被视为限制本申请未在此详述的其他具体实施例。本说明书所使用的词语“实施例”意指实例、示例或例证。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，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所述特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
本申请实施例提供一种显示面板。以下分别进行详细说明。需说明的是，以下实施例的描述顺序不作为对实施例优选顺序的限定。
下面通过具体实施例对本申请提供的显示面板进行详细的阐述。
请参考图1，图1为本申请实施例提供显示面板的一种结构示意图。显示面板100包括衬底101、第一电极102、发光功能层10和第二电极106。其中，第一电极102设置在衬底101上。发光功能层10设置在第一电极102远离衬 底101的一面。发光功能层10包括依次设置在第一电极102上的第一发光层103、电荷生成层104和第二发光层105。第一发光层103包括第一发光子层1033。第二发光层105包括第二发光子层1053。第二电极106设置在第二发光层105远离电荷生成层104的一面。其中，第一发光子层1033具有第一薄膜致密性参数，第一薄膜致密性参数大于或等于第一阈值。第二发光子层1053具有第二薄膜致密性参数，第二薄膜致密性参数大于或等于第二阈值。第一薄膜致密性参数和第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定。
本申请的发明人发现，当第一发光子层1033的第一薄膜致密性参数大于或等于第一阈值时，第二发光子层1053的第二薄膜致密性参数大于或等于第二阈值时，薄膜致密性参数和显示面板100的寿命正相关，薄膜致密性参数越大，薄膜致密度越大，显示面板100的寿命越长。另外，由于多个发光单元串联形成的叠层结构的显示面板100在工作时，会产生热量，热量会导致显示面板100膜层厚度膨胀，导致显示面板100微腔长度变化，微腔长度变化会导致器件的发光颜色偏移，导致显示器件显示不均。本申请的申请人发现，当第一发光子层1033的第一薄膜致密性参数大于或等于第一阈值时，第二发光子层1053的第二薄膜致密性参数大于或等于第二阈值时，可以有效改善由多个发光单元串联形成的显示面板100发热导致的热致光色偏移的现象。
应该理解的是，在本申请实施例中，第一薄膜致密性参数和第一发光子层1033的薄膜致密度有关，薄膜致密度越高，则第一薄膜致密性参数越大。第二薄膜致密性参数和第二发光子层1053的薄膜致密度有关，薄膜致密度越高，则第二薄膜致密性参数越大。
在本申请实施例中，当第一发光子层1033的第一薄膜致密性参数大于或等于第一阈值时，第一薄膜致密性参数越大，则第一发光子层1033的薄膜致密度越大。第二发光子层1053的第二薄膜致密性参数大于或等于第二阈值时，第二薄膜致密性参数越大，则第二发光子层1053的薄膜致密度越大，有效改善了改善由多个发光单元串联形成的显示面板100发热导致的热致光色偏移的现象，进而改善显示面板100显示不均的现象。
需要说明的是，在本申请实施例中，单位受力包括但不限于对第一发光子层1033和第二发光子层1053施加的作用力。这里的单位受力是指对第一发光子层1033和第二发光子层1053施加计量用的最小单元的作用力，例如1N、2N、5N、10N等。
需要说明的是，在本申请实施例中，薄膜产生的形变量包括但不限于薄膜的厚度的形变量。
在一些实施例中，第一薄膜致密性参数和第二薄膜致密性参数由薄膜的厚度方向上，单位受力条件下，薄膜的受力部分产生的厚度形变量决定。具体的，第一薄膜致密性参数可以由如下公式计算得到：X1＝ΔF1/ΔH1，其中，X1为第一薄膜致密性参数，ΔF1为薄膜的厚度方向上的不同作用力的差值，ΔH1为薄膜的受力部分在不同作用力下的厚度差值，0＞X1≥-1.7N/cm。
也就是说，第一阈值为-1.7N/cm，当第一薄膜致密性参数大于等于-1.7，且小于0时，第一薄膜致密性参数越大，则薄膜的致密度越高，显示面板100显示越均匀。
第二薄膜致密性参数可以由如下公式计算得到：X2＝ΔF2/ΔH2，其中，X2为第二薄膜致密性参数，ΔF2为薄膜的厚度方向上的不同作用力的差值，ΔH2为薄膜的受力部分在不同作用力下的厚度差值，0＞X2≥-1.7N/cm。
也就是说，第二阈值为-1.7N/cm，当第二薄膜致密性参数大于等于-1.7，且小于0时，第二薄膜致密性参数越大，则薄膜的致密度越高，显示面板100显示越均匀。
其中，ΔF1或ΔF2可以为对同一受力部分施加两个不同的作用力的差值，ΔH1或ΔH2为对应于两个不同作用力所对应的厚度的差值。或者，ΔF1或ΔF2为对两个不同的受力部分施加的作用力的差值，ΔH1或ΔH2为对应于两个不同作用力所对应的厚度的差值。
需要说明的是，在本申请实施例中，薄膜的单位受力越大，则对应的薄膜的厚度越小。
在本申请中，可以利用原子力显微镜对第一发光子层1033的第一薄膜致密性参数和第二发光子层1053的第二薄膜致密性参数进行表征。在原子力显 微镜的表征下，第一发光子层1033的厚度与第一发光子层1033受到的原子力显微镜的探针的作用力之间呈线性关系，线性关系的斜率即为第二薄膜致密性参数。第二发光子层1053的厚度与第二发光子层1053受到的原子力显微镜的探针的作用力之间呈线性关系，线性关系的斜率即为第二薄膜致密性参数。
具体的，利用原子力显微镜对第一发光子层1033和第二发光子层1053进行表征，然后，建立第一发光子层1033的厚度与第一发光子层1033受到的原子力显微镜的探针的作用力之间的线性关系，第二发光子层1053的厚度与第二发光子层1053受到的原子力显微镜的探针的作用力之间的线性关系，线性关系的斜率越大，则第一发光子层1033和第二发光子层1053的薄膜的致密度越大，则更有利于改善显示面板100的热致色偏移现象。
请参考图2，图2为本实施例利用原子力显微镜对第一发光子层的第一薄膜致密性参数进行表征的示意图。对第一发光子层1033的薄膜致密性参数进行评价具体包括利用原子力显微镜表征的发光子层1033。
原子力显微镜表征第一发光子层1033的过程可以包括在基底S上设置第一发光子层1033，然后，利用探针P对第一发光子层1033的相对厚度进行检测。其中，在基底S上设置第一发光子层1033包括在基底S上设置聚酰亚胺层PI，聚酰亚胺层PI覆盖基底S的一部分。随后，在基底S上蒸镀发光子层1033，第一发光子层1033覆盖聚酰亚胺层PI和基底S，然后再将聚酰亚胺层PI撕除，以此在基底S上制得第一发光子层1033。在本申请实施例中，第一发光子层1033仅覆盖基底S的一部分，以此形成高度差，用于测量第一发光子层1033的相对厚度。利用探针P对第一发光子层1033的相对厚度进行检测的步骤包括：首先，随机选取第一发光子层1033上的任意一点，探针P对其施加第一作用力，然后利用第一作用力探针P施加至基底S上，测得第一发光子层1033的第一相对厚度。随后，随机选取第一发光子层1033上的另一点，探针P对其施加第二作用力，然后利用第二作用力探针P施加至基底S上，测得第一发光子层1033的第二相对厚度。以此反复，利用第三作用力测得第一发光子层1033的第三相对厚度，利用第四作用力测得发光层的第四相对厚度。利用第N作用力测得第一发光子层1033的第N相对厚度。最后，以第一 发光子层1033受到的探针的作用力为横坐标，以第一发光子层1033的厚度为纵坐标，所拟合的线性关系的斜率作为第一发光子层1033的第一薄膜致密性参数。斜率越大则第一发光子层1033的薄膜致密度越大，则更有利于改善显示面板100的热致色偏移的现象。
在本申请实施例中，第一发光子层1033的厚度随着第一发光子层1033受到的探针P的作用力的增大而减小。第一发光子层1033受到的探针P的作用力越大，则对应的第一发光子层1033的厚度越小，本申请实施例以第一发光子层1033受到的探针P的作用力为横坐标，以第一发光子层1033的厚度为纵坐标，拟合得到对应的线性关系。
请参考图3，图3为本申请实施例提供的以mCP(N,N-二咔唑基-3,5-苯)为第一发光子层的发光主体材料拟合的线性关系。在本申请实施例中，以第一发光子层1033受到的探针的作用力(F)为横坐标，以第一发光子层1033的厚度(T)为纵坐标，所拟合的线性关系的斜率作为第一发光子层1033的第一薄膜致密性参数，其中，斜率为-1.69。
应该理解的是，利用原子力显微镜对第二发光子层1053的第二薄膜致密性参数进行表征的原理和第一发光子层1033的原理相同，此处不再赘述。
具体的，本申请实施例利用10种不同的有机发光材料作为第一发光子层1033和第二发光子层1053的主体材料，以此评价第一发光子层1033和第二发光子层1053的成膜致密度以及发光性能。请参考图4，图4为本申请实施例提供的有机发光材料的化学结构式。有机发光材料包括DCB、CBP、CDBP、CBPE、mCP、BCzph、CzC、4CzPBP、TPBi、BCzTPM、BCPPA、NPB、TAPC和Firpic。
请参阅表一，表一为10种不同的有机发光材料作为主体材料的显示面板的性能测试结果。
表一：
Figure PCTCN2022095111-appb-000001
Figure PCTCN2022095111-appb-000002
由表一可知，随着薄膜密度的升高，电压略微下降，外量子效率(EQE)有微弱的提升，寿命提升幅度非常显著。证明薄膜密度越高，对叠层蓝色磷光器件性能越有益。另外，还测试了器件在常温和60摄氏度时的CIEy变化值(ΔCIEy)、发射峰位变化值(ΔP)和半峰宽变化值(ΔFw)，结果如表1所示。由实验结果可知，薄膜密度越高，热致色偏幅度越小。
需要说明的是，斜率为利用上述的原子力显微镜作用于第一发光子层1033和第二发光子层1053的薄膜所测得的。当斜率大于等于-1.7时，热致色偏移幅度越小，显示面板100的寿命提升幅度非常显著。当然，第一阈值也可以选择-1.65、-1.6、-1.55、-1.5、-1.45、-1.4、-1.35、-1.3、-1.25、-1.2、-1.15等。第二阈值也可以选择-1.65、-1.6、-1.55、-1.5、-1.45、-1.4、-1.35、-1.3、-1.25、-1.2、-1.15等。
相较于红色磷光与绿色磷光材料，蓝色磷光材料的寿命特别短，导致显示面板100整体寿命与可靠性降低。在本申请实施例中，以蓝色磷光材料为例，通过提高蓝色磷光材料的成膜的致密度，从而减小热致色偏移幅度，提高蓝色磷光材料的显示面板100的寿命及可靠性，从而提高市场竞争力。
在一些实施例中，第一发光子层1033包括但不限于蓝色磷光发光材料或蓝色荧光发光材料。第一发光子层1033还可以是红色磷光发光材料和绿色磷光发光材料，红色荧光发光材料和绿色荧光发光材料。第二发光子层1053包括但不限于蓝色磷光发光材料或蓝色荧光发光材料。第二发光子层1053还可以是红色磷光发光材料和绿色磷光发光材料，红色荧光发光材料和绿色荧光发光材料。
在本申请实施例中，利用原子力显微镜对第一发光子层1033和第二发光子层1053进行表征，建立第一发光子层1033的厚度与第一发光子层1033受到的原子力显微镜的探针的作用力之间的线性关系，建立第二发光子层1053的厚度与第二发光子层1053受到的原子力显微镜的探针的作用力之间的线性关系，线性关系的斜率越大，线性关系的斜率为第一发光子层1033和第二发光子层1053的薄膜致密性参数，薄膜的致密性参数越大，则第一发光子层1033和第二发光子层1053的致密度越大，则热致偏移幅度越小，显示面板100的寿命越长。在本申请实施例中，当第一薄膜致密性参数大于等于第一阈值时，第二薄膜致密性参数大于等于第二阈值时，显示面板100的寿命大幅度提高。
在本申请的一些实施例中，还可以通过对显示面板100的尺寸形变幅度评价第一发光子层1033和第二发光子层1053的成膜质量。
为了进一步评价第一发光子层1033和第二发光子层1053的成膜质量，显示面板100通电工作状态下，发光功能层10尺寸变化幅度与原有的所述发光功能层10的形状尺寸之间的比值小于或等于7.5％。
需要说明的是，发光功能层10的尺寸变化幅度包括但不限于发光功能层10的厚度膨胀幅度。
在一些实施例中，显示面板100通电工作状态下，发光功能层10的厚度膨胀幅度与发光功能层10原有厚度之间的比值小于或等于7.5％。
例如，发光功能层10通电工作前具有第一厚度a，发光功能层10在预设亮度下点亮预设工作时间后，发光功能层10具有第二厚度b。第二厚度b和第一厚度a的厚度膨胀幅度ω1小于等于7.5％，其中，ω1＝[(b-a)/a]*100％。
在一些实施例中，预设亮度可以是100nit(尼特)，预设时间可以是1小时。具体的，发光功能层10在100nit的亮度下工作1小时后，利用干涉仪对发亮前后的厚度进行测量。
在一些实施例中，还可以通过加热显示面板100的方式对发光功能层10受热前后的厚度进行评价。
其中，显示面板100在加热状态下，发光功能层10尺寸形变幅度与发光功能层10原有形状尺寸之间的比值小于或等于13％。
在一些实施例中，显示面板100在加热状态下，发光功能层10厚度膨胀幅度与发光功能层10原有厚度之间的比值小于或等于13％。
具体的，加热前的发光功能层10具有第一厚度a，发光功能层10在预设温度下加热预设工作时间后，发光功能层10具有第二厚度c；其中，第二厚度c和第一厚度a的厚度膨胀幅度ω2小于等于13％。其中，ω2＝[(c-a)/a]*100％。
预设温度可以是100摄氏度，预设工作时间可以是1小时。具体的，将发光功能层10加热至100摄氏度，在100摄氏度下保持1小时，利用干涉仪对加热后的发光功能层10的厚度进行测量。
请参考表二，表二为显示面板100通电状态下和加热状态下发光功能层10的厚度膨胀幅度。
表二：
有机发光材料 ω1 ω2
DCB 10.1％ 15.1％
CBP 9.4％ 14.5％
CDBP 8.7％ 13.9％
CBPE 8.1％ 13.3％
mCP 7.6％ 12.7％
BCzPh 7.0％ 12.1％
CzC 6.7％ 11.4％
4CzPBP 5.6％ 10.8％
BCzTPM 5.0％ 10.2％
BCPPA 4.7％ 9.6％
由表二可知，通过干涉仪对显示面板100的发光功能层10受热前后的厚度进行测量，求得发光功能层10受热前后的厚度膨胀幅度，厚度膨胀幅度越小，说明第一发光子层1033和第二发光子层1053的成膜质量越好，第一发光子层1033和第二发光子层1053的薄膜致密度越高，显示面板100的性能越好，发光功能层10受热后的厚度膨胀幅度越小。需要说明的是，在实际应用中，ω1的最大值可以选取为7.5％、7％、6.5％、6％、5.5％、5％、4.5％等；ω2的最大值可以选取为13％、12.5％、12％、11.5％、11％、10.5％、10％、9.5％、9％等。
结合表一和表二可知，第一发光子层和第二发光子层的薄膜致密性参数越高，薄膜致密度越高，发光性能越好，发光功能层10受热后的厚度膨胀幅度越小，热致色偏移幅度越小，显示越均匀，显示面板100的寿命越长。
在本申请实施例中，从两个维度对显示面板100的发光功能层10的成膜质量进行评价。包括对第一发光子层1033和第二发光子层1053的密度进行评价，以及将显示面板100作为整体，对显示面板100的发光功能层10受热前后的厚度进行评价。通过两个维度对显示面板100的成膜质量进行评价，表明在原子力显微镜的表征下，斜率越大，发光子层的薄膜致密性参数越大，则发光子层的密度越大。随着发光子层密度的升高，对电压和电致发光峰位(EL Peak)的影响较小，外量子效率(EQE)有微弱的提升，寿命提升幅度非常显著。证明发光子层密度越高，对蓝色磷光材料的发光性能越有益。通过干涉仪对完整的显示面板受热前后的厚度进行测量，求得受热前后的厚度膨胀幅度，厚度膨胀幅度越小，说明第一发光子层1033和第二发光子层1053的成膜质量 越好，第一发光子层1033和第二发光子层1053密度越高，发光性能越好，发光功能层10受热后的厚度膨胀幅度越小。热致色偏移幅度越小，显示越均匀，显示面板100的寿命越长。
请继续参考图1，电荷生成层104包括第一电荷生成层1041和第二电荷生成层1042。第一电荷生成层1041设置在第一发光层103远离第一电极102的一面，第二电荷生成层1042设置在第一电荷生成层1041远离第一发光层103的一面。
其中，第一电荷生成层1041为n-型电荷生成层，第一电荷生成层1041的材料包括n-型电荷生成材料。第二电荷生成层1042为p-型电荷生成层，第二电荷生成层1042的材料包括p-型电荷生成材料。在本申请实施例中，由于电荷生成层104的存在，由电极注入的一个载流子可依次流经两个独立的发光单元，发光效率显著提升。
其中，第一发光层103还包括第一空穴注入子层1031、第一空穴传输子层1032、第一电子传输子层1034和第一电子注入子层1035。其中，第一空穴注入子层1031和第一空穴传输子层1032依次设置在第一电极102上。第一发光子层1033设置在第一空穴传输子层1032上。第一电子传输子层1034和第一电子注入子层1035依次设置在第一发光子层1033上。第一电荷生成层1041和第二电荷生成层1042依次设置在第一电子注入子层1035上。第二发光层105还包括第二空穴注入子层1051、第二空穴传输子层1052、第二电子传输子层1054和第二电子注入子层1055。其中，第二空穴注入子层1051和第二空穴传输子层1052依次设置在第二电荷生成层1042上。第二电子传输子层1054和第二电子注入子层1055依次设置在第二发光子层1053远离第二空穴传输子层1052的一面。
请参考图5，图5为本申请实施例提供的显示面板的一种能级排布方式图。在一些实施例中，第一空穴传输子层1032、第一发光子层1033和第一电子传输子层1034的最低空轨道能级和最高占据轨道能级依次减小。
在本申请实施例中，由于第一空穴传输子层1032、第一发光子层1033和第一电子传输子层1034的最低空轨道能级和最高占据轨道能级依次减小，即 各个相邻有机膜层材料的最高占据轨道(The Highest Occupied Molecular Orbitals)能级和最低空轨道(The Lowest Unoccupied Molecular Orbitals)能级呈阶梯式排列，这样的排列方式有利于载流子的平衡注入和传输，降低能级势垒，从而提高显示面板100的发光效率，进而获得最优的器件性能。
需要说明的是，最高占据轨道指的是在电子占有的分子轨道中，能量最高的分子轨道叫做最高占据轨道，也叫最高占有分子轨道。在未被电子占据的分子轨道中，能量最低的分子轨道称为最低空轨道。
在一些实施例中，电子、空穴能够以1:1的比例平衡注入，实现电子空穴的高效利用。
其中，为了降低从第一电极102注入空穴的势垒，使空穴能从第一电极102有效地注入到显示面板100中。空穴的传输速率一般是大于电子的传输速率，为了让从电极注入的电子和空穴的复合发生在第一发光子层1033中，第一空穴传输子层1032及第一发光子层1033能级结构匹配，且匹配空穴迁移速度。为了降低从第二电极106注入电子的势垒，使电子能从第二电极106有效地注入到显示面板100中。因此，在选择第一电子注入子层1035材料的时候，为了使电子能从第二电极106有效地注入到显示面板100中。降低从阳极注入空穴的势垒，使空穴能从阳极有效地注入到OLED器件中。因此，在选择电子注入层材料的时候，需要考虑材料能级和第二电极106材料的匹配。
在一些实施例中，第一空穴注入子层1031、第一空穴传输子层1032、第一发光子层1033、第一电子传输子层1034和第一电子注入子层1035的最低空轨道能级和最高占据轨道能级依次减小。这样的排列方式有利于载流子的平衡注入和传输，降低能级势垒，从而进一步提高显示面板100的发光效率，进而获得最优的器件性能。
在一些实施例中，第一空穴传输子层1032和第一发光子层1033的最高占据轨道的能级差小于或等于0.2eV，第一电子传输子层1034和第一发光子层1033的最低空轨道的能级差小于等于0.2eV。从而减小相邻的有机膜层间的势垒，进一步提高显示面板100的发光效率。
具体的，第一空穴传输子层1032和第一发光子层1033的最高占据轨道的 能级差可以是0.05eV、0.08eV、0.12eV、0.15eV、0.18eV或0.2eV中的任意一者。第一空穴传输子层1032和第一发光子层1033的最低空轨道的能级差可以是0.05eV、0.08eV、0.12eV、0.15eV、0.18eV或0.2eV中的任意一者。从而减小相邻的有机膜层间的势垒，进一步提高显示面板100的发光效率。
在一些实施例中，第二空穴传输子层1052、第二发光子层1053和第二电子传输子层1054的最低空轨道能级和最高占据轨道能级依次减小。
在本申请实施例中，由于第二空穴传输子层1052、第二发光子层1053和第二电子传输子层1054的最低空轨道能级和最高占据轨道能级依次减小，即各个相邻有机膜层材料的最高占据轨道(The Highest Occupied Molecular Orbitals)能级和最低空轨道(The Lowest Unoccupied Molecular Orbitals)能级呈阶梯式排列，这样的排列方式有利于载流子的平衡注入和传输，降低能级势垒，从而提高显示面板100的发光效率，进而获得最优的器件性能。
在一些实施例中，电子、空穴能够以1:1的比例平衡注入，实现电子空穴的高效利用。
其中，为了降低从第一电极102注入空穴的势垒，使空穴能从第一电极102有效地注入到显示面板100中。空穴的传输速率一般是大于电子的传输速率，为了让从电极注入的电子和空穴的复合发生在第一发光子层1033中，第二空穴传输子层1052及第二发光子层1053能级结构匹配，且匹配空穴迁移速度。为了降低从第二电极106注入电子的势垒，使电子能从第二电极106有效地注入到显示面板100中。因此，在选择第二电子注入子层1055材料的时候，为了使电子能从第二电极106有效地注入到显示面板100中。降低从阳极注入空穴的势垒，使空穴能从阳极有效地注入到OLED器件中。因此，在选择电子注入层材料的时候，需要考虑材料能级和第二电极106材料的匹配。
在一些实施例中，第二空穴注入子层1051、第二空穴传输子层1052、第二发光子层1053、第二电子传输子层1054和第二电子注入子层1055的最低空轨道能级和最高占据轨道能级依次减小。这样的排列方式有利于载流子的平衡注入和传输，降低能级势垒，从而进一步提高显示面板100的发光效率，进而获得最优的器件性能。
在一些实施例中，第二空穴传输子层1052和第二发光子层1053的最高占据轨道的能级差小于或等于0.2eV，第二电子传输子层1054和第二发光子层1053的最低空轨道的能级差小于等于0.2eV。从而减小相邻的有机膜层间的势垒，进一步提高显示面板100的发光效率。
具体的，第二空穴传输子层1052和第二发光子层1053的最高占据轨道的能级差可以是0.05eV、0.08eV、0.12eV、0.15eV、0.18eV或0.2eV中的任意一者。第二空穴传输子层1052和第二发光子层1053的最低空轨道的能级差可以是0.05eV、0.08eV、0.12eV、0.15eV、0.18eV或0.2eV中的任意一者。从而减小相邻的有机膜层间的势垒，进一步提高显示面板100的发光效率。
在一些实施例中，显示面板100还包括薄膜晶体管结构层，薄膜晶体管结构层设置在衬底101上，薄膜晶体管结构层用于驱动显示面板100发光。
在一些实施例中，第一电极102为阳极，第一电极102的材料为氧化铟锡、银和氧化铟锡的叠层材料。第二电极106为阴极，第二电极106的材料为镁和银合金材料。
相应的，本申请实施例还提供一种显示面板的制作方法，显示面板100的制作方法包括以下步骤：
步骤B001：提供衬底。
步骤B002：在衬底上形成第一电极，其中，第一电极为氧化铟锡、银和氧化铟锡的叠层材料。
步骤B003：在第一电极上形成第一发光层。其中，第一发光层包括依次层叠设置的第一空穴注入子层、第一空穴传输子层、第一发光子层、第一电子传输子层、第一电子注入子层。其中，第一空穴传输子层的材料可以是NPB(N,N′-二(1-萘基)-N,N′-二苯基-1,1′-联苯-4-4′-二胺)，其厚度介于10纳米至60纳米。在一具体的实施例中，第一空穴传输子层的厚度可以是20纳米。第一发光子层为有机发光材料，其掺杂的有机发光材料的浓度小于2％。发光子层的蒸镀速率小于等于1.5埃/秒。在一实施例中，第一发光子层的蒸镀速率为1.0埃/秒。其中，有机发光材料的主体材料可以是DCB、CBP、CDBP、CBPE、mCP、BCzph、CzC、4CzPBP、TPBi、BCzTPM、BCPPA、NPB、TAPC、 和Irpic中的至少一种。第一发光子层的厚度可以介于10纳米至30纳米。在一具体的实施例中，第一发光子层的厚度可以是20纳米。
在一些实施例中，在第一电极上形成第一发光层的步骤包括在第一空穴传输子层上形成第一电子阻挡层，第一电子阻挡层的材料可以是TAPC(4,4'-环己基二[N,N-二(4-甲基苯基)苯胺])。第一电子阻挡层的厚度为可以介于2纳米至10纳米。在一具体的实施例中，第一电子阻挡层的厚度可以是5纳米。
步骤B004：在第一发光层上形成电荷生成层，电荷生成层包括第一电荷生成层和第二电荷生成层。第一电荷生成层为n-型电荷生成层，第二电荷生成层为p-型电荷生成层。
在一些实施例中，第一电荷生成层包括n型电荷生成材料，例如TPBi掺杂5％的Yb，其厚度为100nm，第二电荷生成层包括p型电荷生成材料，例如NPB掺杂5％的HATCN(2,3,6,7,10,11-六氰基-1,4,5,8,9,12-六氮杂苯并菲)，其厚度为100nm。
步骤B004：在电荷生成层上形成第二发光层，其中，第二发光层包括依次层叠设置的第二空穴注入子层、第二空穴传输子层、第二发光子层、第二电子传输子层、第二电子注入子层。其中，第二空穴传输子层的材料可以是NPB(N,N′-二(1-萘基)-N,N′-二苯基-1,1′-联苯-4-4′-二胺)，其厚度介于10纳米至60纳米。在一具体的实施例中，第二空穴传输子层的厚度可以是20纳米。第而发光子层为有机发光材料，其掺杂的有机发光材料的浓度小于2％。发光子层的蒸镀速率小于等于1.5埃/秒。在一实施例中，第二发光子层的蒸镀速率为1.0埃/秒。其中，有机发光材料的主体材料可以是DCB、CBP、CDBP、CBPE、mCP、BCzph、CzC、4CzPBP、TPBi、BCzTPM、BCPPA、NPB、TAPC、和Firpic中的至少一种。第二发光子层的厚度可以介于10纳米至30纳米。在一具体的实施例中，第二发光子层的厚度可以是20纳米。
在一些实施例中，第二空穴传输子层为NPB，其厚度为20nm。第二电子传输子层的材料为TPBi，其厚度为35nm。第二电子注入子层Yb(镱)且厚度为1nm。
在一些实施例中，在电荷生成层上形成第二发光层的步骤包括在第二空穴 传输子层上形成第二电子阻挡层，第二电子阻挡层的材料可以是TAPC(4,4'-环己基二[N,N-二(4-甲基苯基)苯胺])。第二电子阻挡层的厚度为可以介于2纳米至10纳米。在一具体的实施例中，第二电子阻挡层的厚度可以是5纳米。
步骤B005：在第二发光层能远离电荷生成层的一面蒸镀第二电极。其中，第二电极的材料可以包括银和镁。第二电极的蒸镀速率小于或等于3埃/秒，在一实施例中，第二电极的蒸镀速率可以是2埃/秒。第二电极的厚度介于10纳米至50纳米，例如，第二电极的厚度可以是13.2纳米。
在一些实施例中，第二电极的Mg掺杂浓度为9％。
综上所述，虽然本申请已以优选实施例揭露如上，但上述优选实施例并非用以限制本申请，本领域的普通技术人员，在不脱离本申请的精神和范围内，均可作各种更动与润饰，因此本申请的保护范围以权利要求界定的范围为准。

Claims (20)

  1. 一种显示面板，其包括：
    衬底，
    第一电极，设置在所述衬底上；
    发光功能层，设置在所述第一电极远离所述衬底的一面，所述发光功能层包括依次设置在所述第一电极上的第一发光层、电荷生成层和第二发光层，所述第一发光层包括第一发光子层，所述第二发光层包括第二发光子层；
    第二电极，设置在所述第二发光层远离所述电荷生成层的一面；
    其中，所述第一发光子层具有第一薄膜致密性参数，所述第一薄膜致密性参数大于或等于第一阈值，所述第二发光子层具有第二薄膜致密性参数，所述第二薄膜致密性参数大于或等于第二阈值，所述第一薄膜致密性参数和所述第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定。
  2. 根据权利要求1所述的显示面板，其中，所述第一薄膜致密性参数和所述第二薄膜致密性参数由薄膜的厚度方向上，单位受力条件下，薄膜的受力部分产生的厚度形变量决定。
  3. 根据权利要求2所述的显示面板，其中，所述第一薄膜致密性参数可以由如下公式计算得到：
    X1＝ΔF1/ΔH1；
    其中，ΔF1为薄膜的厚度方向上的不同作用力的差值；ΔH1为薄膜的受力部分在不同作用力下的厚度差值；
    所述第二薄膜致密性参数可以由如下公式计算得到：
    X2＝ΔF2/ΔH2；
    其中，ΔF2为薄膜的厚度方向上的不同作用力的差值；ΔH2为薄膜的受力部分在不同作用力下的厚度差值。
  4. 根据权利要求3所述的显示面板，其中，所述第一阈值为-1.7，所述第一薄膜致密性参数小于0；
    所述第二阈值为-1.7，且所述第二薄膜致密性参数小于0。
  5. 根据权利要求1所述的显示面板，其中，所述显示面板通电工作状态 下，所述发光功能层的尺寸形变幅度与所述发光功能层原有形状尺寸之间的比值小于或等于7.5％。
  6. 根据权利要求5所述的显示面板，其中，所述显示面板通电工作状态下，所述发光功能层的厚度膨胀幅度与所述发光功能层原有厚度之间的比值小于或等于7.5％。
  7. 根据权利要求1所述的显示面板，其中，所述显示面板在加热状态下，所述发光功能层的尺寸形变幅度与所述发光功能层原有形状尺寸之间的比值小于或等于13％。
  8. 根据权利要求7所述的显示面板，其中，所述显示面板在加热状态下，所述发光功能层的厚度膨胀幅度与所述发光功能层原有厚度之间的比值小于或等于13％。
  9. 根据权利要求1所述的显示面板，其中，所述电荷生成层包括第一电荷生成层和第二电荷生成层，所述第一电荷生成层设置在所述第一发光层远离所述第一电极的一面，所述第一电荷生成层包括n-型电荷生成材料，所述第二电荷生成层设置在所述第一电荷生成层远离所述第一发光层的一面，所述第二电荷生成层包括p-型电荷生成材料。
  10. 根据权利要求9所述的显示面板，其中，所述第一发光层包括依次层叠设置的第一空穴注入子层、第一空穴传输子层、所述第一发光子层、第一电子传输子层和第一电子注入子层；
    所述第二发光层包括依次层叠设置的第二空穴注入子层、第二空穴传输子层、所述第二发光子层、第二电子传输子层和第二电子注入子层。
  11. 根据权利要求10所述的显示面板，其中，所述第一所述空穴传输子层、所述第一发光子层和所述第一电子传输子层的最高占据轨道的能级和最低空轨道的能级依次减小，所述第二所述空穴传输子层、所述第二发光子层和所述第二电子传输子层的最高占据轨道的能级和最低空轨道的能级依次减小。
  12. 根据权利要求11所述的显示面板，其中，所述第一空穴传输子层和所述第一发光子层的最高占据轨道的能级差小于或等于0.2eV，所述第一电子传输子层和所述第一发光子层的最低空轨道的能级差小于等于0.2 eV；
    所述第二空穴传输子层和所述第二发光子层的最高占据轨道的能级差小于或等于0.2eV，所述第二电子传输子层和所述第二发光子层的最低空轨道的能级差小于等于0.2eV。
  13. 根据权利要求1所述的显示面板，其中，所述第一发光子层包括蓝色磷光发光材料或蓝色荧光发光材料，所述第二发光子层包括蓝色磷光发光材料或蓝色荧光发光材料。
  14. 根据权利要求1所述的显示面板，其中，所述第一发光子层和所述第二发光子层包括红色磷光发光材料或红色荧光发光材料。
  15. 根据权利要求1所述的显示面板，其中，所述第一发光子层和所述第二发光子层包括绿色磷光发光材料或绿色荧光发光材料。
  16. 根据权利要求1所述的显示面板，其中，所述第一电极为阳极，所述第二电极为阴极。
  17. 一种显示面板，其包括：
    衬底，
    第一电极，设置在所述衬底上；
    发光功能层，设置在所述第一电极远离所述衬底的一面，所述发光功能层包括依次设置在所述第一电极上的第一发光层、电荷生成层和第二发光层，所述第一发光层包括第一发光子层，所述第二发光层包括第二发光子层；
    第二电极，设置在所述第二发光层远离所述电荷生成层的一面；
    其中，所述第一发光子层具有第一薄膜致密性参数，所述第一薄膜致密性参数大于或等于第一阈值，所述第二发光子层具有第二薄膜致密性参数，所述第二薄膜致密性参数大于或等于第二阈值，所述第一薄膜致密性参数和所述第二薄膜致密性参数由单位受力条件下薄膜产生的形变量决定，其中，所述薄膜致密性参数通过原子力显微镜表征。
  18. 根据权利要求17所述的显示面板，其中，所述第一薄膜致密性参数和所述第二薄膜致密性参数由薄膜的厚度方向上，单位受力条件下，薄膜的受力部分产生的厚度形变量决定。
  19. 根据权利要求18所述的显示面板，其中，所述第一薄膜致密性参数 可以由如下公式计算得到：
    X1＝ΔF1/ΔH1；
    其中，ΔF1为薄膜的厚度方向上的不同作用力的差值；ΔH1为薄膜的受力部分在不同作用力下的厚度差值；
    所述第二薄膜致密性参数可以由如下公式计算得到：
    X2＝ΔF2/ΔH2；
    其中，ΔF2为薄膜的厚度方向上的不同作用力的差值；ΔH2为薄膜的受力部分在不同作用力下的厚度差值。
  20. 根据权利要求19所述的显示面板，其中，所述第一阈值为-1.7，所述第一薄膜致密性参数小于0；
    所述第二阈值为-1.7，且所述第二薄膜致密性参数小于0。
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