Display panel

Abstract

The embodiment of the present application discloses a display panel, which comprises a first electrode layer, a light-emitting structure and a second electrode layer. The light-emitting structure comprises a first light-emitting unit, a second light-emitting unit and a third light-emitting unit which are sequentially stacked, the first light-emitting unit, the second light-emitting unit and the third light-emitting unit are independently selected from red light-emitting units, green light-emitting units and blue light-emitting units, and the light-emitting colors of the first light-emitting unit, the second light-emitting unit and the third light-emitting unit are different from each other. The light-emitting structure is provided with a light conversion layer, the light conversion layer is arranged on the side of the green light-emitting unit and / or the blue light-emitting unit close to the light-emitting surface of the light-emitting structure, and the light conversion layer is doped with red photoluminescence particles. In the present application, the light conversion layer is arranged in the light-emitting structure, the color rendering index of the white light display panel is improved, and the performance of the white light display panel is improved.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a display panel. Background Technology

[0002] With the rapid development of LED technology and the gradual improvement of LED luminous efficacy, the application of LEDs will become increasingly widespread. Currently, white LED devices achieve white light emission by mixing red, green, and blue materials in different proportions. These three materials, after being processed by solution treatment, spin-coating, or inkjet printing, are integrated into the LED device and can serve as effective exciton radiative recombination centers.

[0003] White light-emitting diode (LED) devices require the injection of electrons and holes to operate. The simplest white LED device consists of a cathode, an electron transport layer, an emissive layer, a hole transport layer, and an anode. In a white LED device, the emissive layer is located between the electron transport layer and the hole transport layer. When a forward bias voltage is applied across the LED device, electrons and holes enter the emissive layer through the electron transport layer and the hole transport layer, respectively, and then recombine to emit light within the emissive layer.

[0004] However, current white light-emitting diode devices still suffer from a low color rendering index, resulting in low color fidelity.

[0005] Therefore, there is an urgent need for a white light-emitting diode device with a high color rendering index. Summary of the Invention

[0006] This application provides a display panel to solve the problem of low color rendering index in existing white light display panels.

[0007] This application provides a display panel, including:

[0008] First electrode layer;

[0009] A light-emitting structure is disposed on a first electrode layer. The light-emitting structure includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked sequentially. The first, second, and third light-emitting units are independently selected from red, green, and blue light-emitting units, respectively. The first, second, and third light-emitting units emit different colors. The light-emitting structure includes a light conversion layer disposed on the side of the green and / or blue light-emitting units near the light-emitting surface of the light-emitting structure. The light conversion layer is doped with red photoluminescent particles.

[0010] The second electrode layer is disposed on the side of the light-emitting structure away from the first electrode layer.

[0011] Optionally, in some embodiments of this application, the red photoluminescent particles are used to receive light emitted by the green and / or blue light-emitting units and emit red light, while the light-emitting structure emits white light.

[0012] Optionally, in some embodiments of this application, the red photoluminescent particles are selected from CdSe-based quantum dot materials, CdZnSe-based quantum dot materials, InP-based quantum dot materials, and ZnSe-based quantum dot materials.

[0013] Optionally, in some embodiments of this application, the doping concentration of the red photoluminescent particles in the light conversion layer is 10%-35%.

[0014] Optionally, in some embodiments of this application, the first light-emitting unit includes a first light-emitting layer, a first electron transport layer, and a first hole transport layer, wherein the light conversion layer, the first hole transport layer, the first light-emitting layer, and the first electron transport layer are sequentially stacked on the first electrode layer.

[0015] Optionally, in some embodiments of this application, the light conversion layer material is selected from poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, polyaniline, and polythiophene.

[0016] Optionally, in some embodiments of this application, the first light-emitting unit includes a first hole injection layer, a first light-emitting layer, and a first electron transport layer, wherein the first hole injection layer, the light conversion layer, the first light-emitting layer, and the first electron transport layer are sequentially stacked on the first electrode layer.

[0017] Optionally, in some embodiments of this application, the light conversion layer material is selected from poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine and 4,4′-bis(9-carbazole)biphenyl.

[0018] Optionally, in some embodiments of this application, the first light-emitting unit includes a first hole injection layer, a first hole transport layer, and a first light-emitting layer, wherein the first hole injection layer, the first hole transport layer, the first light-emitting layer, and the light conversion layer are sequentially stacked on the first electrode layer.

[0019] Optionally, in some embodiments of this application, the light conversion layer material is selected from ZnO, Zn x Mg y O, Znm1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1.

[0020] Optionally, in some embodiments of this application, the light conversion layer is disposed between the first light-emitting unit and the second light-emitting unit, or between the second light-emitting unit and the third light-emitting unit. Optionally, in some embodiments of this application, the light conversion layer material is selected from indium tin oxide, indium zinc oxide, zinc aluminum oxide, indium gallium zinc oxide, zinc oxide, and zinc manganese oxide.

[0021] Optionally, in some embodiments of this application, the second light-emitting unit includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, and a second electron transport layer stacked sequentially; the third light-emitting unit includes a third hole injection layer, a third hole transport layer, a third light-emitting layer, and a third electron transport layer stacked sequentially; the display panel further includes a first transparent conductive layer disposed between the first light-emitting unit and the second light-emitting unit and / or a second transparent conductive layer disposed between the second light-emitting unit and the third light-emitting unit.

[0022] This application discloses a display panel comprising a first electrode layer, a light-emitting structure, and a second electrode layer. The light-emitting structure is disposed on the first electrode layer and includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked sequentially. The first, second, and third light-emitting units are independently selected from red, green, and blue light-emitting units, respectively, and each unit emits a different color. A light conversion layer is provided in the light-emitting structure, located on the side of the green and / or blue light-emitting units closest to the light-emitting surface of the light-emitting structure. The light conversion layer is doped with red photoluminescent particles, causing the light-emitting structure to emit white light. The second electrode layer is located on the side of the light-emitting structure furthest from the first electrode layer. In this application, by providing a light conversion layer in the light-emitting structure, the color rendering index of the white light display panel is improved, thereby enhancing the performance of the white light display panel. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the first structure of the display panel provided in the embodiments of this application.

[0025] Figure 2 This is a schematic diagram of a second structure of the display panel provided in an embodiment of this application.

[0026] Figure 3 This is a schematic diagram of a third structure of the display panel provided in the embodiments of this application.

[0027] Figure 4 This is a schematic diagram of the fourth structure of the display panel provided in the embodiments of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0029] This application provides a display panel. The details are described below.

[0030] Please see Figure 1 , Figure 1 This is a schematic diagram of a first structure of a display panel provided in an embodiment of this application. This application provides a display panel 10. The display panel 10 includes a first electrode layer 100, a light-emitting structure 200, and a second electrode layer 300.

[0031] In one embodiment, the display panel 10 further includes a substrate 400. The substrate 400 can be a rigid substrate or a flexible substrate. The flexible substrate can be a polyimide substrate. The rigid substrate can be a glass substrate.

[0032] The first electrode layer 100 is disposed on the substrate 400.

[0033] In one embodiment, the first electrode layer 100 is an anode or a cathode. In this embodiment, the first electrode layer 100 is an anode.

[0034] In one embodiment, the material of the first electrode layer 100 includes one or a combination of indium tin oxide, indium zinc oxide, aluminum zinc oxide, and indium gallium zinc oxide. In this embodiment, the material of the first electrode layer 100 is indium tin oxide.

[0035] In one embodiment, the thickness H1 of the first electrode layer 100 is 50 nanometers to 1000 nanometers. Specifically, the thickness H1 of the first electrode layer 100 can be 50 nanometers, 500 nanometers, 750 nanometers, 900 nanometers, or 1000 nanometers, etc. In this embodiment, the thickness H1 of the first electrode layer 100 is 600 nanometers.

[0036] In this embodiment, the thickness H1 of the first electrode layer 100 is set to 50 nanometers-1000 nanometers. Within this thickness range, the resistance of the first electrode layer 100 is low, resulting in minimal resistance to current flow and thus improving its conductivity. If the thickness H1 of the first electrode layer 100 is less than 50 nanometers, the resistance of the first electrode layer 100 becomes too low, causing damage to the display panel 10. If the thickness H1 of the first electrode layer 100 is greater than 1000 nanometers, the resistance of the first electrode layer 100 becomes too high, affecting its conductivity and preventing the display panel 10 from displaying properly.

[0037] The light-emitting structure 200 is disposed on the side of the first electrode layer 100 away from the substrate 400. The light-emitting structure 200 includes a first light-emitting unit 210, a second light-emitting unit 220, and a third light-emitting unit 230 stacked sequentially, wherein the first light-emitting unit 210, the second light-emitting unit 220, and the third light-emitting unit 230 are independently selected from red light-emitting units, green light-emitting units, and blue light-emitting units, respectively. The first light-emitting unit 210, the second light-emitting unit 220, and the third light-emitting unit 230 emit different colors. The light-emitting structure 200 is provided with a light conversion layer 240. The light conversion layer 240 is disposed on the side of the green light-emitting unit and / or the blue light-emitting unit near the light-emitting surface of the light-emitting structure. The light conversion layer 240 is doped with red photoluminescent particles 241.

[0038] The first light-emitting unit 210 includes a first hole transport layer 211, a first light-emitting layer 212, and a first electron transport layer 213. The light conversion layer 240, the first hole transport layer 211, the first light-emitting layer 212, and the first electron transport layer 213 are sequentially stacked on the first electrode layer 100.

[0039] In this embodiment, red photoluminescent particles 241 are doped into the light conversion layer 240. These red photoluminescent particles 241 receive light emitted by the green and / or blue light-emitting units and emit red light, thus enabling the light conversion layer 240 to have a light conversion effect. The light-emitting structure 200 emits white light, improving the low color rendering index of the display panel 10 and enhancing its performance. The light conversion layer 240 is disposed between the first electrode layer 100 and the first hole transport layer 211. This allows the light conversion layer 240 to serve as the first hole injection layer for the first light-emitting unit 210. Furthermore, because the energy level, mobility, and optical properties of the first electrode layer 100 are similar to those of the light conversion layer 240, the conversion effect of the light conversion layer 240 is further improved, enhancing the color rendering index of the display panel 10. The color rendering index is improved, thereby enhancing the performance of the display panel 10. Red photoluminescent particles 241 are doped into the light conversion layer 240, meaning that red photoluminescent particles 241 are doped into the first hole injection layer. This allows the first hole injection layer to simultaneously function as both a light conversion layer and a hole injection layer, eliminating the need for a separate light conversion layer 240 and reducing the thickness of the display panel 10, thus achieving a thinner and lighter design. The light conversion layer 240 is disposed on the first electrode layer 100, meaning that red photoluminescent particles 241 are doped into the hole injection layer on the first electrode layer 100 near the light-emitting side to form the light conversion layer 240. This allows for a wider range of choices for the thickness W1 of the light conversion layer 240, thereby improving the conversion effect of the light conversion layer 240 and ultimately increasing the color rendering index of the display panel.

[0040] The color rendering index (CRI) refers to the effect of a test light source on the color appearance of an object compared to a standard light source; in other words, the fidelity of the colors. A higher CRI indicates that the object's color is closer to its true color under the test light source.

[0041] In one embodiment, the light conversion layer 240 material comprises poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, polyaniline, and polythiophene. In this embodiment, the first hole injection layer material is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0042] In one embodiment, the red photoluminescent particle 241 has a core-shell structure with a shell covering the core. The core material is selected from CdSe-based quantum dot materials, CdZnSe-based quantum dot materials, InP-based quantum dot materials, and ZnSe-based quantum dot materials, and the shell material is selected from CdS and ZnS. In this embodiment, the core layer is an InP-based quantum dot material, and the shell is CdS and ZnS.

[0043] In this embodiment, the red photoluminescent particles 241 adopt a core-shell structure with a shell covering the core layer. Since the band gap of the shell layer is larger than that of the core layer, the light conversion layer 240 expands the range of photon collection spectrum while avoiding the influence of defects in the core layer on the light emission of the light conversion layer 240. Furthermore, the coupling characteristics of the core layer can be avoided by adjusting the thickness of the shell layer, thereby improving the stability of the display panel 10.

[0044] In one embodiment, the core layer material is selected from CdSe-based quantum dot materials, CdZnSe-based quantum dot materials, InP-based quantum dot materials, and ZnSe-based quantum dot materials, while the shell layer material is selected from CdS and ZnS. Furthermore, the particle size of the red photoluminescent particles 241 is set to 7-8 nanometers. In this embodiment, the light conversion layer 240 material has a particle size of 8 nanometers, causing the red photoluminescent particles to emit red light.

[0045] In one embodiment, the photoluminescence wavelength of the light conversion layer 240 material is 600 nm to 630 nm.

[0046] In one embodiment, the full width at half maximum (FWHM) of the photoluminescence of the red photoluminescent particle 241 is 40 nm to 90 nm. Specifically, the FWHM of the photoluminescence of the red photoluminescent particle 241 can be 40 nm, 50 nm, 60 nm, 75 nm, 80 nm, or 90 nm, etc.

[0047] Half-peak width refers to the width of a chromatographic peak at half its height. It is the distance between two points where a straight line drawn through the midpoint of the peak height intersects the two sides of the peak.

[0048] In one embodiment, a spectrum with continuous light and a wide half-width at half maximum (WHM) is selected, i.e., the WHM of the photoluminescence of the red photoluminescent particles 241 is 40 nm to 90 nm, thereby improving the color rendering index of the white light display panel 10 and thus improving the performance of the display panel.

[0049] The photoluminescence mechanism is that when quantum dots are irradiated by external light, they gain energy, become excited, and emit light.

[0050] In one embodiment, the doping concentration of the red photoluminescent particles 241 in the light conversion layer 240 is 10%-35%. Specifically, the doping concentration of the red photoluminescent particles 241 can be 10%, 12%, 14%, 25%, 30%, or 35%, etc. In this embodiment, the doping concentration of the red photoluminescent particles 241 is 28%.

[0051] In this embodiment, the doping concentration of the red photoluminescent particles 241 in the light conversion layer 240 is set to 10%-35% to improve the color rendering index of the display panel 10. If the doping concentration of the red photoluminescent particles 241 in the light conversion layer 240 is set to less than 10%, the light conversion layer 240 needs to be made sufficiently thick to ensure the color rendering index of the display panel 10, which increases the film thickness of the device and is not conducive to achieving a thin and light design. If the doping concentration of the red photoluminescent particles 241 in the light conversion layer 240 is set to greater than 35%, the high concentration of red photoluminescent particles 241 causes phase separation between the red photoluminescent particles 241 and the organic matter therein, affecting the color rendering index of the display panel 10.

[0052] Phase separation refers to the phenomenon where a multi-component system sometimes separates into several phases with different compositions and structures when external conditions such as temperature and pressure change. In one embodiment, the thickness W1 of the light conversion layer 240 is 50 nm to 500 nm. Specifically, the thickness W1 of the light conversion layer 240 can be 50 nm, 80 nm, 160 nm, 240 nm, 300 nm, 400 nm, 480 nm, or 500 nm, etc. In this embodiment, the thickness W1 of the light conversion layer 240 is 200 nm.

[0053] In one embodiment, setting the thickness W1 of the light conversion layer 240 to 50 nanometers-500 nanometers improves the light conversion effect of the light conversion layer 240. Setting the thickness W1 of the light conversion layer 240 to less than 50 nanometers reduces the light conversion efficiency of the light conversion layer 240, affecting the color rendering index of the display panel 10. Setting the thickness W1 of the light conversion layer 240 to greater than 500 nanometers results in a higher proportion of light other than red being converted to red, which is detrimental to the white light emitted by the display panel 10.

[0054] In one embodiment, the material of the first hole transport layer 211 includes one or a combination of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine, and 4,4′-bis(9-carbazole)biphenyl. In this embodiment, the material of the first hole transport layer 211 is 4,4′-bis(9-carbazole)biphenyl.

[0055] In one embodiment, the thickness D1 of the first hole transport layer 211 is 15 nanometers to 40 nanometers. Specifically, the thickness D1 of the first hole transport layer 211 can be 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, or 40 nanometers, etc. In this embodiment, the thickness D1 of the first hole transport layer 211 is 20 nanometers.

[0056] In this embodiment, the thickness D1 of the first hole transport layer 211 is set between 15 nanometers and 40 nanometers to ensure the transmission efficiency of holes in the first hole transport layer 211, thereby ensuring the normal display of the display panel 10.

[0057] The first light-emitting layer 212 is disposed on the side of the first hole transport layer 211 away from the first electrode layer 100.

[0058] In one embodiment, the first light-emitting layer 212 includes one of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. In this embodiment, the first light-emitting layer 212 is a blue light-emitting layer, that is, the first light-emitting unit 210 is a blue light-emitting unit.

[0059] In one embodiment, the first light-emitting layer 212 is a core-shell structure with a shell covering the core layer. The band gap of the shell layer is larger than that of the core layer.

[0060] In one embodiment, the core material includes at least one selected from CdSe, CdZnSe, InP, and ZnSe. The shell material includes one or a combination of CdS and ZnS. In this embodiment, the core material is ZnSe, and the shell material is CdS.

[0061] In one embodiment, the particle size of the first light-emitting layer 212 material is 1 nanometer to 2 nanometers. In this embodiment, the particle size of the first light-emitting layer 212 material is 2 nanometers.

[0062] In this application, CdSe, CdZnSe, InP and ZnSe are used as core layer materials, and CdS and ZnS are used as shell layer materials. The particle size of the first light-emitting layer 212 material is set to 1 nanometer-2 nanometers, so that the first light-emitting layer 212 emits blue light.

[0063] In one embodiment, the photoluminescence wavelength of the first light-emitting layer 212 material is 465 nm to 480 nm.

[0064] In one embodiment, the thickness T1 of the first light-emitting layer 212 is 10 nanometers to 40 nanometers. Specifically, the thickness T1 of the first light-emitting layer 212 can be 10 nanometers, 12 nanometers, 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, or 40 nanometers, etc. In this embodiment, the thickness T1 of the first light-emitting layer 212 is 20 nanometers.

[0065] In this embodiment, the thickness T1 of the first light-emitting layer 212 is set to 10 nanometers-40 nanometers, so that the first light-emitting layer 212 can emit light normally, thereby enabling the display panel 10 to display normally.

[0066] In one embodiment, the material of the first electron transport layer 213 is selected from ZnO and Zn. x Mg yO, Zn m1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1. In this embodiment, the first electron transport layer 213 is made of Zn. 0.95 Mg 0.05 O.

[0067] In one embodiment, the thickness h1 of the first electron transport layer 213 is 20 nanometers to 60 nanometers. Specifically, the thickness h1 of the first electron transport layer 213 can be 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, 40 nanometers, 50 nanometers, 54 nanometers, or 60 nanometers, etc. In this embodiment, the thickness h1 of the first electron transport layer 213 is 30 nanometers.

[0068] In this embodiment, the thickness h1 of the first electron transport layer 213 is set to 20 nanometers-60 nanometers to ensure the electron transport performance of the first electron transport layer 213, thereby ensuring the normal display of the display panel 10.

[0069] In one embodiment, the display panel 10 includes a first transparent conductive layer 500. The first transparent conductive layer 500 is disposed on the side of the first electron transport layer 213 away from the first electrode layer 100.

[0070] In one embodiment, the material of the first transparent conductive layer 500 is selected from indium tin oxide, indium zinc oxide, zinc aluminum oxide, indium gallium zinc oxide, zinc oxide, and zinc manganese oxide. In this embodiment, the material of the first transparent conductive layer 500 is indium zinc oxide.

[0071] In one embodiment, the thickness R1 of the first transparent conductive layer 500 is 50 nanometers to 1000 nanometers. Specifically, the thickness R1 of the first transparent conductive layer 500 can be 50 nanometers, 500 nanometers, 750 nanometers, 900 nanometers, or 1000 nanometers, etc. In this embodiment, the thickness R1 of the first transparent conductive layer 500 is 100 nanometers.

[0072] In this embodiment, the thickness R1 of the first transparent conductive layer 500 is set to 50 nm-1000 nm to avoid the influence of the subsequent second hole injection layer 221 on the first electron transport layer 213, thereby ensuring the injection and electron transport of the first electron transport layer 213, and thus ensuring the normal display of the display panel 10. If the thickness R1 of the first transparent conductive layer 500 is set to less than 50 nm, the second hole injection layer 221 will affect the electron injection and transport efficiency of the first electron transport layer 213, which is not conducive to the normal display of the display panel 10. If the thickness R1 of the first transparent conductive layer 500 is set to 1000 nm, the resistance of the first transparent conductive layer 500 is increased, which reduces the conductivity of the first transparent conductive layer 500, thereby affecting the display performance of the display panel 10.

[0073] The second light-emitting unit 220 includes a second hole injection layer 221, a second hole transport layer 222, a second light-emitting layer 223, and a second electron transport layer 224, which are sequentially stacked on the first transparent conductive layer 500.

[0074] In one embodiment, the material of the second hole injection layer 221 is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, polyaniline, and polythiophene. In this embodiment, the material of the second hole injection layer 221 is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate.

[0075] In one embodiment, the thickness W2 of the second hole injection layer 221 is 15 nanometers to 50 nanometers. Specifically, the thickness W2 of the second hole injection layer 221 can be 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, 40 nanometers, 48 ​​nanometers, or 50 nanometers, etc. In this embodiment, the thickness W2 of the second hole injection layer 221 is 25 nanometers.

[0076] In this embodiment, the thickness W2 of the second hole injection layer 221 is set to 15 nanometers-50 nanometers to ensure the hole injection efficiency of the second hole injection layer 221, thereby ensuring the normal display of the display panel 10.

[0077] The first electron transport layer 213, the first transparent conductive layer 500, and the second hole injection layer 221 constitute the first charge layer 600 of the light-emitting structure 200. The first charge layer 600 is used to provide the holes and electrons required by the light-emitting structure 200.

[0078] In this embodiment, the first charge layer 600 is composed of a first electron transport layer 213, a first transparent conductive layer 500, and a second hole injection layer 221. Since the first transparent conductive layer 500 is an n-type semiconductor and the second hole injection layer 221 is a p-type semiconductor, the two form a pn junction when they come into contact. When the conduction band of the first transparent conductive layer 500 is equal to or less than the highest occupied molecular orbital (HOMO) energy level of the second hole injection layer 221, electrons and holes are generated at the pn junction when an external electric field is applied. Electrons are injected into the light-emitting unit through the first transparent conductive layer 500, and holes are also injected into another light-emitting unit. That is, the first charge layer 600 can generate enough electrons and holes, thereby avoiding the problem of energy transfer caused by the stacked arrangement of the light-emitting units of the display panel 10, avoiding the problem of uneven display of the display panel 10, and thus improving the stability of the display panel 10.

[0079] In this embodiment, red photoluminescent particles 241 are doped into the light conversion layer 240, so that the light conversion layer 240 serves as the hole injection layer of the first light-emitting unit 210 while also having a light conversion effect, thereby improving the color rendering index of the white light display panel 10 and thus improving the performance of the white light display panel.

[0080] In one embodiment, the second hole transport layer 222 is made of one or a combination of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine, and 4,4′-bis(9-carbazole)biphenyl. In this embodiment, the second hole transport layer 222 is made of polyvinylcarbazole.

[0081] In one embodiment, the thickness D2 of the second hole transport layer 222 is 15 nanometers to 40 nanometers. Specifically, the thickness D2 of the second hole transport layer 222 can be 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, or 40 nanometers, etc. In this embodiment, the thickness D2 of the second hole transport layer 222 is 25 nanometers.

[0082] In this embodiment, the thickness D2 of the second hole transport layer 222 is set to 15 nanometers-40 nanometers to ensure the transmission efficiency of holes in the second hole transport layer 222, thereby ensuring the normal display of the display panel 10.

[0083] In one embodiment, the second light-emitting layer 223 includes one of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. In this embodiment, the second light-emitting layer 223 is a green light-emitting layer, that is, the second light-emitting unit 220 is a green light-emitting unit.

[0084] In one embodiment, the second luminescent layer 223 is a core-shell structure with a shell covering the core layer. The core layer material includes one of CdSe, CdZnSe, InP, and ZnSe, and the shell layer material includes one or a combination of CdS and ZnS. In this embodiment, the core layer material is CdZnSe, and the shell material is CdS.

[0085] In one embodiment, the particle size of the second light-emitting layer 223 material is 3 nanometers to 6 nanometers. In this embodiment, the particle size of the second light-emitting layer 223 material is 5 nanometers.

[0086] In this embodiment, CdSe, CdZnSe, InP and ZnSe are used as core layer materials, and CdS and ZnS are used as shell layer materials. The particle size of the second light-emitting layer 223 material is set to 3 nanometers-6 nanometers, so that the second light-emitting layer 223 emits green light.

[0087] In one embodiment, the photoluminescence wavelength of the second light-emitting layer 223 material is 535 nm to 555 nm. In one embodiment, the thickness T2 of the second light-emitting layer 223 is 10 nm to 40 nm. Specifically, the thickness T2 of the second light-emitting layer 223 can be 10 nm, 12 nm, 15 nm, 20 nm, 24 nm, 34 nm, 38 nm, or 40 nm, etc. In this embodiment, the thickness T2 of the second light-emitting layer 223 is 15 nm.

[0088] In this embodiment, the thickness T2 of the second light-emitting layer 223 is set to 10 nanometers-40 nanometers, so that the second light-emitting layer 223 can emit light normally, thereby enabling the display panel 10 to display normally.

[0089] In one embodiment, the material of the second electron transport layer 224 is selected from ZnO and Zn. x Mg y O, Zn m1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1.

[0090] In one embodiment, the material of the second electron transport layer 224 may be Zn. 0.98 Al 0.02 O, Zn 0.9 Mg 0.05 Li 0.05 O, Zn 0.9 Mg 0.1 O or Zn 0.88 Mg 0.12 O, etc. In this embodiment, the material of the second electron transport layer 224 is Zn.0.95 Mg 0.05 O.

[0091] In one embodiment, the thickness h2 of the second electron transport layer 224 is 20 nanometers to 60 nanometers. Specifically, the thickness h2 of the second electron transport layer 224 can be 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, 40 nanometers, 50 nanometers, 54 nanometers, or 60 nanometers, etc. In this embodiment, the thickness h2 of the second electron transport layer 224 is 38 nanometers.

[0092] In this embodiment, the thickness h2 of the second electron transport layer 224 is set to 20 nanometers-60 nanometers to ensure the electron transport performance of the second electron transport layer 224, thereby ensuring the normal display of the display panel 10.

[0093] In one embodiment, the display panel 10 further includes a second transparent conductive layer 700. The second transparent conductive layer 700 is disposed on the second electron transport layer 224.

[0094] In one embodiment, the material of the second transparent conductive layer 700 is selected from indium tin oxide, indium zinc oxide, zinc aluminum oxide, indium gallium zinc oxide, zinc oxide, and zinc manganese oxide. In this embodiment, the material of the second transparent conductive layer 700 is indium zinc oxide.

[0095] In one embodiment, the thickness R2 of the second transparent conductive layer 700 is 50 nanometers to 1000 nanometers. Specifically, the thickness R2 of the second transparent conductive layer 700 can be 50 nanometers, 500 nanometers, 750 nanometers, 900 nanometers, or 1000 nanometers, etc. The thickness R2 of the second transparent conductive layer 700 is 500 nanometers.

[0096] In this embodiment, the thickness R2 of the second transparent conductive layer 700 is set to 50 nm-1000 nm to avoid the influence of the subsequent third hole injection layer 231 on the second electron transport layer 224, thereby ensuring the injection and electron transport of the second electron transport layer 224, and thus ensuring the normal display of the display panel 10. If the thickness R2 of the second transparent conductive layer 600 is set to less than 50 nm, the third hole injection layer 231 will affect the electron injection and transport efficiency of the second electron transport layer 224, which is not conducive to the normal display of the display panel 10. If the thickness R2 of the second transparent conductive layer 600 is set to 1000 nm, the resistance of the second transparent conductive layer 600 is increased, which reduces the conductivity of the second transparent conductive layer 600, thereby affecting the display performance of the display panel 10.

[0097] The third light-emitting unit 230 includes a third hole injection layer 231, a third hole transport layer 232, a third light-emitting layer 233 and a third electron transport layer 234, which are sequentially stacked on the second transparent conductive layer 700.

[0098] In one embodiment, the material of the third hole injection layer 231 is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, polyaniline, and polythiophene. In this embodiment, the material of the third hole injection layer 231 is polythiophene.

[0099] In one embodiment, the thickness W3 of the third hole injection layer 231 is 15 nanometers to 50 nanometers. Specifically, the thickness W3 of the third hole injection layer 231 can be 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, 40 nanometers, 48 ​​nanometers, or 50 nanometers, etc. In this embodiment, the thickness W3 of the third hole injection layer 231 is 39 nanometers.

[0100] In this embodiment, the thickness W3 of the third hole injection layer 231 is set to 15 nanometers-50 nanometers to ensure the hole injection efficiency of the third hole injection layer 231, thereby ensuring the normal display of the display panel 10.

[0101] The second electron transport layer 224, the second transparent conductive layer 700, and the third hole injection layer 231 constitute the second charge layer 800 of the light-emitting structure 200. The second charge layer 800 is used to provide the holes and electrons required by the light-emitting structure 200.

[0102] In this embodiment, the second charge layer 800 is composed of a second electron transport layer 224, a second transparent conductive layer 700, and a third hole injection layer 231. Since the second transparent conductive layer 700 is an n-type semiconductor and the third hole injection layer 231 is a p-type semiconductor, the two form a pn junction when they come into contact. When the conduction band of the second transparent conductive layer 700 is equal to or less than the highest occupied molecular orbital (HOMO) energy level of the third hole injection layer 231, electrons and holes are generated at the pn junction when an external electric field is applied. Electrons are injected into the light-emitting unit through the second transparent conductive layer 700, and holes are also injected into another light-emitting unit. That is, the second charge layer 800 can generate enough electrons and holes, thereby avoiding the problem of energy transfer caused by the stacked arrangement of the light-emitting units of the display panel 10, avoiding the problem of uneven display of the display panel 10, and thus improving the stability of the display panel 10.

[0103] In one embodiment, the third hole transport layer 232 material comprises one or a combination of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine, and 4,4′-bis(9-carbazole)biphenyl. In this embodiment, the third hole transport layer 232 material is poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine).

[0104] In one embodiment, the thickness D3 of the third hole transport layer 232 is 15 nanometers to 40 nanometers. Specifically, the thickness D3 of the third hole transport layer 232 can be 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, or 40 nanometers, etc. In this embodiment, the thickness D3 of the third hole transport layer 232 is 18 nanometers.

[0105] In this embodiment, the thickness D3 of the third hole transport layer 232 is set to 15 nanometers-40 nanometers to ensure the transmission efficiency of holes in the third hole transport layer 232, thereby ensuring the normal display of the display panel 10.

[0106] In one embodiment, the third light-emitting layer 233 includes one of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. In this embodiment, the third light-emitting layer 233 is a red light-emitting layer, that is, the third light-emitting unit 230 is a red light-emitting unit.

[0107] In one embodiment, the third luminescent layer 233 is a core-shell structure with a shell covering the core layer. The core layer material includes one of CdSe, CdZnSe, InP, and ZnSe. The shell material includes one or a combination of CdS and ZnS. In this embodiment, the core layer material is ZnSe, and the shell material is CdS and ZnS.

[0108] In one embodiment, the particle size of the third light-emitting layer 233 material is 7-8 nanometers. In this embodiment, the particle size of the third light-emitting layer 233 material is 8 nanometers.

[0109] In this embodiment, CdSe, CdZnSe, InP and ZnSe are used as core layer materials, and CdS and ZnS are used as shell layer materials. The particle size of the third light-emitting layer 233 material is set to 7-8 nanometers, so that the third light-emitting layer 233 emits red light.

[0110] In one embodiment, the photoluminescence wavelength of the third light-emitting layer 233 material is 615 nm to 625 nm.

[0111] In one embodiment, the thickness T3 of the third light-emitting layer 233 is 10 nanometers to 40 nanometers. Specifically, the thickness T3 of the third light-emitting layer 233 can be 10 nanometers, 12 nanometers, 15 nanometers, 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, or 40 nanometers, etc. In this embodiment, the thickness T3 of the third light-emitting layer 233 is 22 nanometers.

[0112] In this embodiment, the thickness T3 of the third light-emitting layer 233 is set to 10 nanometers-40 nanometers, so that the third light-emitting layer 233 can emit light normally, thereby enabling the display panel 10 to display normally.

[0113] In one embodiment, the material of the third electron transport layer 234 is selected from ZnO and Zn x Mg y O, Zn m1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1. In this embodiment, the material of the third electron transport layer 234 is Zn. 0.85 Mg 0.05 Li 0.1 O.

[0114] In one embodiment, the thickness h3 of the third electron transport layer 234 is 20 nanometers to 60 nanometers. Specifically, the thickness h3 of the third electron transport layer 234 can be 20 nanometers, 24 nanometers, 34 nanometers, 38 nanometers, 40 nanometers, 50 nanometers, 54 nanometers, or 60 nanometers, etc. In this embodiment, the thickness h3 of the third electron transport layer 234 is 54 nanometers.

[0115] In one embodiment, the display panel 10 further includes a second electrode layer 300. The second electrode layer 300 is disposed on the side of the third electron transport layer 234 away from the first electrode layer 100.

[0116] In one embodiment, the material of the second electrode layer 300 includes gold, silver, aluminum, and their alloys. In this embodiment, the material of the second electrode layer 300 is gold.

[0117] In one embodiment, the thickness H2 of the second electrode layer 300 is 80 nm to 500 nm. Specifically, the thickness H2 of the second electrode layer 300 can be 80 nm, 120 nm, 340 nm, 480 nm, or 500 nm, etc. In this embodiment, the thickness H2 of the second electrode layer 300 is 100 nm. In this embodiment, the thickness H2 of the second electrode layer 300 is 490 nm. The second electrode layer 300 is an anode or a cathode; in this embodiment, the second electrode layer 300 is a cathode.

[0118] This application provides a display panel that provides a light conversion layer doped with red photoluminescent particles between a first electrode layer and a first hole transport layer. Specifically, a first hole injection layer doped with red photoluminescent particles is provided between the first electrode layer and the first hole transport layer. This allows the first hole injection layer to have a light conversion effect without affecting its own performance, thereby improving the color rendering index of the white light display panel and thus improving the performance of the white light display panel.

[0119] Please see Figure 2 , Figure 2This is a schematic diagram of a second structure of the display panel provided in an embodiment of this application. It should be noted that the second structure differs from the first structure in that:

[0120] The light conversion layer 240 is disposed between the first hole injection layer 211 and the first light emission layer 212.

[0121] In one embodiment, the light conversion layer 240 material is selected from one or a combination of several of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine, and 4,4′-bis(9-carbazole)biphenyl. In this embodiment, the light conversion layer 240 material is 4,4′-bis(9-carbazole)biphenyl.

[0122] In this embodiment, a light conversion layer 240 is disposed between the first hole injection layer 211 and the first light-emitting layer 212, so that the light conversion layer 240 can serve as the first hole transport layer of the first light-emitting unit 210. Red photoluminescent particles are doped into the first hole transport layer, so that the first hole transport layer has the performance of a hole transport layer while also having a light conversion effect. This avoids the problem of low color rendering index of the display panel 10 due to the absorption of red light by other light, thereby improving the color rendering index of the display panel 10 and thus improving the display performance of the display panel 10.

[0123] Please see Figure 3 , Figure 3 This is a schematic diagram of a third structure of the display panel provided in an embodiment of this application. It should be noted that the third structure differs from the first structure in that:

[0124] The light conversion layer 240 is disposed between the first light-emitting layer 212 and the first transparent conductive layer 500.

[0125] In one embodiment, the light conversion layer material is selected from ZnO and Zn x Mg y O, Zn m1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1. In this embodiment, the light conversion layer material is Zn. 0.92 Mg 0.08 O.

[0126] In this embodiment, a light conversion layer 240 is disposed between the first light-emitting layer 212 and the first transparent conductive layer 500, so that the light conversion layer 240 can serve as the first electron transport layer of the first light-emitting unit 210. Red photoluminescent particles are not doped into the first hole injection layer 213, but are doped into the first electron transport layer. This allows the first electron transport layer to have both the performance of an electron transport layer and the light conversion effect, avoiding the problem of low color rendering index of the display panel 10 due to the absorption of red light by other light, thus improving the color rendering index of the display panel 10 and thereby improving the display performance of the display panel 10.

[0127] Please see Figure 4 , Figure 4 This is a schematic diagram of a fourth structure of the display panel provided in an embodiment of this application. It should be noted that the fourth structure differs from the first structure in that:

[0128] The light conversion layer 240 is disposed between the first electron transport layer 213 and the second hole injection layer 221 or between the second electron transport layer 224 and the third hole injection layer 231.

[0129] In one embodiment, the light conversion layer 240 material is selected from indium tin oxide, indium zinc oxide, zinc aluminum oxide, indium gallium zinc oxide, zinc oxide, and zinc manganese oxide.

[0130] In this embodiment, the light conversion layer 240 is disposed between the first electron transport layer 213 and the second hole injection layer 221 or between the second electron transport layer 224 and the third hole injection layer 231, so that the light conversion layer 240 can serve as the first transparent conductive layer or the second transparent conductive layer of the light-emitting structure 200. Red photoluminescent particles are doped into the first transparent conductive layer or the second transparent conductive layer, so that the first transparent conductive layer or the second transparent conductive layer has the performance of a transparent conductive layer while having a light conversion effect. This avoids the problem of low color rendering index of the display panel 10 due to the absorption of red light by other light, improves the color rendering index of the display panel 10, and thus improves the display performance of the display panel 10.

[0131] In one embodiment, the red photoluminescent particles 241 may also be doped into the film layers of the second light-emitting unit 220 and the third light-emitting unit 230 to form a light conversion layer 240. For example, a second hole injection layer 221, a second electron transport layer 224, or a third hole injection layer 231, etc., and the light conversion layer 240 is disposed on the side of the green light-emitting layer and / or the blue light-emitting layer near the light-emitting surface of the light-emitting structure 200.

[0132] In one embodiment, the films in the first light-emitting unit 210, the second light-emitting unit 220 and the third light-emitting unit 230, except for the first light-emitting layer 212, the second light-emitting layer 223 and the third light-emitting layer 233, are all doped with a small amount of red photoluminescent particles 241, and the light conversion layer 240 is disposed on the side of the green light-emitting layer and / or the blue light-emitting layer near the light-emitting surface of the light-emitting structure 200.

[0133] The display panel 10 of this application can be a white quantum dot light-emitting diode display panel or a white organic light-emitting diode display panel.

[0134] The display panel 10 of this application can be a photoluminescent display panel or an electroluminescent display panel.

[0135] This application discloses a display panel, which includes a first electrode layer, a light-emitting structure, and a second electrode layer. The light-emitting structure is disposed on the first electrode layer and includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked sequentially. The first, second, and third light-emitting units are independently selected from red, green, and blue light-emitting units, respectively, and each unit emits a different color. The light-emitting structure includes a light conversion layer doped with red light-emitting particles, and this light conversion layer is disposed on the side of the green and / or blue light-emitting units near the light-emitting surface of the light-emitting structure. The second electrode layer is disposed on the first electrode layer of the light-emitting structure. In this application, by incorporating a light conversion layer in the light-emitting structure, the color rendering index of the white light display panel is improved, thereby enhancing the performance of the white light display panel.

[0136] The above provides a detailed description of a display panel provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A display panel, characterized in that, include: First electrode layer; A light-emitting structure is disposed on a first electrode layer. The light-emitting structure includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked sequentially. The first, second, and third light-emitting units are independently selected from red, green, and blue light-emitting units, respectively. The first, second, and third light-emitting units emit different colors. The light-emitting structure includes a light conversion layer disposed on the side of the green and / or blue light-emitting units near the light-emitting surface of the light-emitting structure. The light conversion layer is made of a material doped with red photoluminescent particles, where the red photoluminescent particles are core-shell materials, and the doping concentration of the red photoluminescent particles in the light conversion layer is 10%-35%. A second electrode layer is disposed on the side of the light-emitting structure away from the first electrode layer; The first light-emitting unit includes a first hole transport layer, a first light-emitting layer, and a first electron transport layer arranged sequentially, with the light conversion layer located between the first electrode layer and the first hole transport layer; the light conversion layer material is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, polyaniline, and polythiophene; or, The first light-emitting unit includes a first hole injection layer, a first light-emitting layer, and a first electron transport layer arranged sequentially, with the light conversion layer located between the first hole injection layer and the first light-emitting layer; the light conversion layer material is selected from poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), poly(N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine), polyvinylcarbazole, 4,4′,4″-tris(carbazole-9-yl)triphenylamine, and 4,4′-bis(9-carbazole)biphenyl; or, The first light-emitting unit includes a first hole injection layer, a first hole transport layer, and a first light-emitting layer disposed sequentially, wherein the first light-emitting layer is located between the first hole transport layer and the light conversion layer; the light conversion layer material is selected from ZnO and Zn. x Mg y O, Zn m1 Al m2 O and Zn n1 Mg n2 Li n3 O, where x+y=1, m1+m2=1, n1+n2+n3=1; or, The light conversion layer is disposed between the first light-emitting unit and the second light-emitting unit or between the second light-emitting unit and the third light-emitting unit; the material of the light conversion layer is selected from indium tin oxide, indium zinc oxide, zinc aluminum oxide, indium gallium zinc oxide, zinc oxide, and zinc manganese oxide.

2. The display panel according to claim 1, characterized in that, The red photoluminescent particles are used to receive the light emitted by the green light-emitting unit and / or the blue light-emitting unit and emit red light, while the light-emitting structure emits white light.

3. The display panel according to claim 1, characterized in that, The red photoluminescent particles are selected from CdSe-based quantum dot materials, CdZnSe-based quantum dot materials, InP-based quantum dot materials, and ZnSe-based quantum dot materials.

4. The display panel according to any one of claims 1 to 3, characterized in that, The second light-emitting unit includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, and a second electron transport layer stacked sequentially; the third light-emitting unit includes a third hole injection layer, a third hole transport layer, a third light-emitting layer, and a third electron transport layer stacked sequentially. The display panel further includes a first transparent conductive layer disposed between the first light-emitting unit and the second light-emitting unit and / or a second transparent conductive layer disposed between the second light-emitting unit and the third light-emitting unit.

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