Perovskite light emitting diode and preparation method thereof

Abstract

The application relates to the field of semiconductor optoelectronic devices, in particular to a perovskite light-emitting diode and a preparation method thereof. The perovskite light-emitting diode comprises a substrate, a transparent conductive electrode arranged on the substrate, an organic hole transport layer arranged on the transparent conductive electrode and covering part of the transparent conductive electrode, so that another part of the transparent conductive electrode is exposed, a two-dimensional perovskite hole transport layer covering the organic hole transport layer, a spacer layer covering the two-dimensional perovskite hole transport layer, a perovskite light-emitting layer covering the spacer layer, an electron transport layer covering the perovskite light-emitting layer, and a metal conductive electrode covering the electron transport layer and comprising N electrode units arranged at intervals, wherein N is a positive integer. The two-dimensional perovskite replaces the traditional organic hole transport layer as a hole transport material, can improve the hole transport performance, effectively improve the brightness of the light-emitting diode, and realize better carrier injection balance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor optoelectronic devices, in particular to a perovskite light-emitting diode and a preparation method thereof. BACKGROUND

[0002] At present, the HOMO energy level of some light-emitting materials is deep, so a hole transport material with a suitable energy level is needed as the hole transport layer of the device, which is generally an organic semiconductor material. However, the commonly used organic hole transport layer has low mobility, which is not conducive to the injection of holes. Therefore, a hole transport material with suitable mobility and energy level is the key to further improving the performance of perovskite photodiode devices. SUMMARY

[0003] Based on this, the present application provides a perovskite light-emitting diode and a preparation method thereof, which has a deep HOMO energy level, is conducive to energy level matching in the device, further improves the hole injection capability, and realizes better carrier injection balance.

[0004] According to an aspect of the present application, a perovskite light-emitting diode is provided, comprising:

[0005] a substrate;

[0006] a transparent conductive electrode disposed on the substrate;

[0007] an organic hole transport layer disposed on the transparent conductive electrode and covering part of the area of the transparent conductive electrode, so that another part of the area of the transparent conductive electrode is exposed;

[0008] a two-dimensional perovskite hole transport layer covering the organic hole transport layer;

[0009] a spacer layer covering the two-dimensional perovskite hole transport layer;

[0010] a perovskite light-emitting layer covering the spacer layer;

[0011] an electron transport layer covering the perovskite light-emitting layer;

[0012] a metal conductive electrode covering the electron transport layer, comprising N spaced electrode units, N being a positive integer.

[0013] According to an embodiment of the present application, wherein,

[0014] The organic hole transport layer is a 3,4-vinyldioxylthiophene polymer and a polystyrene sulfonate sodium polystyrene sulfonate aqueous solution, and the thickness of the organic hole transport layer is 30-50 nm.

[0015] According to an embodiment of the present application, wherein,

[0016] The material of the transparent conductive electrode is indium tin oxide;

[0017] The material of the electron transport layer is one of tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene or 2,4,6-tris[3-(diphenylphosphoryl)phenyl]-1,3,5-triazole, and a mixture of lithium fluoride, and the thickness of the electron transport layer is 30 nm to 50 nm;

[0018] The thickness of the metal conductive electrode is 80 nm to 120 nm.

[0019] According to an embodiment of the present application, wherein,

[0020] The material of the spacer layer is polyvinylpyrrolidone with a molecular weight of 30,000 to 55,000 g / mol;

[0021] The thickness of the spacer layer is 1 nm to 3 nm.

[0022] According to an embodiment of the present application, wherein,

[0023] The material of the two-dimensional perovskite hole transport layer is one of phenylethylamine lead chloride, phenylethylamine lead bromide or phenylethylamine lead iodide; and the thickness of the two-dimensional perovskite hole transport layer is 20 nm to 40 nm.

[0024] The material of the perovskite light-emitting layer is quasi-two-dimensional perovskite, and the thickness of the perovskite light-emitting layer is 30 nm to 60 nm.

[0025] According to another aspect of the present application, a method for preparing the perovskite light-emitting diode described above is provided, comprising:

[0026] Preparation of a transparent conductive electrode on the substrate;

[0027] Spin coating of the organic hole transport layer on the transparent conductive electrode and annealing;

[0028] Preparation of the two-dimensional perovskite hole transport layer on the organic hole transport layer by spin coating and annealing;

[0029] Spin coating of the spacer layer on the two-dimensional perovskite hole transport layer;

[0030] Spin coating of the perovskite light-emitting layer on the spacer layer and annealing;

[0031] Evaporation of the electron transport layer on the perovskite light-emitting layer;

[0032] Evaporation of the metal conductive electrode on the electron transport layer;

[0033] The organic hole transport layer covers a portion of the transparent conductive electrode, and the organic hole transport layer is removed from another portion of the transparent conductive electrode, exposing the other portion of the transparent conductive electrode.

[0034] According to an embodiment of the present invention, the preparation of the two-dimensional perovskite hole transport layer by spin-coating on the organic hole transport layer, followed by annealing, includes:

[0035] Dissolve one of phenethylamine lead chloride, phenethylamine lead bromide, or phenethylamine lead iodide in dimethyl sulfoxide to form a first mixed solution;

[0036] Spin-coat the first mixed solution onto the organic hole transport layer.

[0037] The first mixed solution was thermally annealed in a glove box under a nitrogen atmosphere to obtain the two-dimensional perovskite hole transport layer.

[0038] The concentration of lead ions in the above mixed solution is between 0.15M and 0.25M.

[0039] According to an embodiment of the present invention, the spin-coating of the spacer layer onto the two-dimensional perovskite hole transport layer comprises:

[0040] The above-mentioned polyvinylpyrrolidone was dissolved in chlorobenzene to form a second mixed solution;

[0041] The mixed solution was spin-coated onto the surface of the two-dimensional perovskite hole transport layer to obtain the spacer layer.

[0042] According to an embodiment of the present invention, the process of spin-coating a perovskite light-emitting layer onto the spacer layer and annealing includes:

[0043] The above-mentioned quasi-two-dimensional perovskite was prepared;

[0044] The aforementioned quasi-two-dimensional perovskite was spin-coated onto the aforementioned spacer layer;

[0045] Chlorobenzene is added dropwise during the spin coating process described above;

[0046] The aforementioned quasi-two-dimensional perovskite was thermally annealed in a glove box under a nitrogen atmosphere to obtain the perovskite luminescent layer.

[0047] According to an embodiment of the present invention, the preparation of the above-mentioned quasi-two-dimensional perovskite includes:

[0048] Phenethylamine iodide, cesium iodide, and lead iodide were dissolved in dimethyl sulfoxide solution to obtain a third mixed solution;

[0049] Stir the above third mixed solution at room temperature and let it stand until the precipitate in the above third mixed solution has completely precipitated, to obtain a clear liquid on the surface and a precipitate in the lower layer.

[0050] The quasi-two-dimensional perovskite is obtained by filtering the above-mentioned surface layer supernatant.

[0051] As can be seen from the above technical solutions, the perovskite light-emitting diode and the preparation method thereof provided by the present application have the following beneficial effects:

[0052] The perovskite light-emitting diode and the preparation method thereof provided by the present application use two-dimensional perovskite as a hole transport layer, and replace the traditional organic hole transport layer with two-dimensional perovskite PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 as a hole transport material. Firstly, the hole transport performance can be improved, and the hole mobility of the two-dimensional perovskite is about 10 cm 2 / (V·s), which is much higher than the hole mobility of the traditional organic hole transport material, thereby effectively improving the brightness of the light-emitting diode. Secondly, the two-dimensional perovskite has a deeper HOMO energy level, which is beneficial to the energy level matching in the device, further improves the hole injection capacity, and realizes better carrier injection balance. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 FIG. 1 is a structure schematic diagram of the perovskite light-emitting diode of the embodiment of the present application;

[0054] Figure 2 FIG. 2 is a preparation flowchart of the perovskite light-emitting diode of the embodiment of the present application;

[0055] Figure 3 FIG. 3 is a current density and voltage relationship curve of the two-dimensional perovskite hole transport layer of the embodiment of the present application using PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or the traditional organic hole transport material TFB;

[0056] Figure 4 FIG. 4 is a brightness and voltage relationship curve of the two-dimensional perovskite hole transport layer of the embodiment of the present application using PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or the traditional organic hole transport material TFB;

[0057] Figure 5 FIG. 5 is an external quantum efficiency and current density relationship curve of the two-dimensional perovskite hole transport layer of the embodiment of the present application using PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or the traditional organic hole transport material TFB.

[0058] In the figure:

[0059] 10-substrate;

[0060] 20-transparent conductive electrode;

[0061] 30-organic hole transport layer;

[0062] 40 - two-dimensional perovskite hole transport layer;

[0063] 50 - spacer layer;

[0064] 60 - perovskite light emitting layer;

[0065] 70 - electron transport layer;

[0066] 80 - metal conductive electrode. DETAILED DESCRIPTION

[0067] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to specific embodiments and the accompanying drawings.

[0068] At present, the HOMO energy level of some light emitting materials is deep, so a hole transport material with suitable energy level is needed as the hole transport layer of the device, which is generally an organic semiconductor material. However, the commonly used organic hole transport layer has low mobility, which is not conducive to the injection of holes. Therefore, a hole transport material with suitable mobility and energy level is the key to further improve the performance of perovskite photodiode devices.

[0069] The quasi-two-dimensional perovskite material has high exciton binding energy due to its self-organizing quantum well. In addition, it also has adjustable optical band gap, high photoluminescence quantum yield, narrow half-height width of light emitting peak, and low-cost solution processing, which has broad prospects in the field of light emitting diodes and displays.

[0070] According to the overall inventive concept of one aspect of the present application, a perovskite light emitting diode is provided, which comprises a substrate 10, a transparent conductive electrode 20, an organic hole transport layer 30, a two-dimensional perovskite hole transport layer 40, a spacer layer 50, a perovskite light emitting layer 60, an electron transport layer 70 and a metal conductive electrode 80.

[0071] The transparent conductive electrode 20 is arranged on the substrate 10 and serves as a support and as a positive electrode of the device.

[0072] The organic hole transport layer 30 is arranged on the transparent conductive electrode 20 and covers part of the area of the transparent conductive electrode 20, so that another part of the area of the transparent conductive electrode 20 is exposed.

[0073] The two-dimensional perovskite hole transport layer 40 is arranged on the organic hole transport layer 30.

[0074] The organic hole transport layer 30 and the two-dimensional perovskite hole transport layer 40 are used for transporting holes.

[0075] The spacer layer 50 is covered on the two-dimensional perovskite hole transport layer 40, and is used to separate the upper and lower perovskites to prevent mutual solubility of the solutions during preparation.

[0076] The perovskite light-emitting layer 60 is covered on the spacer layer 50, and is used for carrier radiation recombination and light emission.

[0077] The electron transport layer 70 is covered on the perovskite light-emitting layer 60, and is used for electron transport.

[0078] The metal conductive electrode 80 is covered on the electron transport layer 70, and is used as a device cathode, and includes N electrode units arranged at intervals, where N is a positive integer.

[0079] The application provides a perovskite light-emitting diode with a two-dimensional perovskite as a hole transport layer and a preparation method thereof. The two-dimensional perovskite PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 is used to replace a conventional organic hole transport layer 30 as a hole transport material, so that the hole transport performance can be improved. The three-dimensional perovskite has a high mobility (10-10 2 cm 2 / (V·s)) due to the particularity of the structure. The carrier mobility is anisotropic, and the carrier mobility is the highest on the (100), (010) and (001) planes.

[0080] The structure of the two-dimensional perovskite is that the (100) plane of the three-dimensional perovskite is sandwiched between two organic molecules, so that the hole mobility is slightly lower than that of the three-dimensional perovskite, about 10 cm 2 / (V·s), but is still much higher than the hole mobility (about 10 -3 cm 2 / (V·s)) of the conventional organic hole transport material, so that the brightness of the light-emitting diode is effectively improved.

[0081] Secondly, the two-dimensional perovskite has a spontaneous quantum well structure, so that the HOMO energy level is deep, which is beneficial to the energy level matching in the device, further improves the hole injection capacity, and realizes better carrier injection balance.

[0082] According to the embodiment of the application, the material of the substrate 10 can be glass.

[0083] According to the embodiment of the application, the organic hole transport layer 30 is a 3,4-vinyldioxylthiophene polymer and a polystyrene sulfonate sodium polystyrene sulfonate aqueous solution (m-PEDOT: PSS), and the thickness of the organic hole transport layer 30 is 30 nm to 50 nm.

[0084] According to the embodiment of the application, wherein,

[0085] The transparent conductive electrode 20 is made of indium tin oxide (ITO).

[0086] The electron transport layer 70 is made of one of the following materials: tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane (3TPYMB / LiF), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (PO-T2T / LiF), or 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazole (TPBi / LiF), mixed with lithium fluoride. The thickness of the electron transport layer 70 is 30 nm to 50 nm.

[0087] The thickness of the metal conductive electrode 80 is 80 nm to 120 nm.

[0088] According to an embodiment of the present invention, wherein,

[0089] The spacer layer 50 is made of polyvinylpyrrolidone (PVP) with a molecular weight of 30,000 to 55,000 g / mol;

[0090] The thickness of the spacer layer 50 is 1 nm to 3 nm.

[0091] The spacer layer 50 serves two purposes: firstly, it protects the lower two-dimensional perovskite hole transport layer 40, preventing DMSO from dissolving the lower two-dimensional perovskite layer during spin coating to prepare the upper perovskite luminescent layer 60; secondly, it passivates defects in the two-dimensional perovskite layer, reduces non-radiative recombination centers, and improves radiative recombination efficiency.

[0092] According to an embodiment of the present invention, wherein,

[0093] The two-dimensional perovskite hole transport layer 40 is made of one of phenylethylamine lead chloride (PEA2PbCl4), phenylethylamine lead bromide (PEA2PbBr4), or phenylethylamine lead iodide (PEA2PbI4); the thickness of the two-dimensional perovskite hole transport layer 40 is 20 nm to 40 nm.

[0094] The perovskite luminescent layer 60 is made of quasi-two-dimensional perovskite (PEA2(CsPbI3)PbI4), and the thickness of the perovskite luminescent layer 60 is 30nm to 60nm.

[0095] According to another aspect of the present invention, a method for fabricating a perovskite light-emitting diode is provided, comprising:

[0096] S100: A transparent conductive electrode 20 is fabricated on the substrate 10;

[0097] S200: Spin-coating an organic hole transport layer 30 onto the transparent conductive electrode 20 and then annealing it;

[0098] S300: spin-coating a two-dimensional perovskite hole transport layer 40 on the organic hole transport layer 30 and annealing;

[0099] S400: spin-coating a spacer layer 50 on the two-dimensional perovskite hole transport layer 40;

[0100] S500: spin-coating a perovskite light-emitting layer 60 on the spacer layer 50 and annealing;

[0101] S600: evaporating an electron transport layer 70 on the perovskite light-emitting layer 60;

[0102] S700: evaporating a metal conductive electrode 80 on the electron transport layer 70;

[0103] S800: covering part of the transparent conductive electrode 20 with the organic hole transport layer 30, removing the organic hole transport layer 30 from another part of the transparent conductive electrode 20, and exposing the other part of the transparent conductive electrode 20.

[0104] The perovskite light-emitting diode with a two-dimensional perovskite as a hole transport layer and the preparation method thereof provided by the present application use a two-dimensional perovskite PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 to replace the conventional organic hole transport layer 30 as a hole transport material, which can improve the hole transport performance. 2 cm 2 The carrier mobility of the two-dimensional perovskite is anisotropic, and the carrier mobility is highest on the (100), (010) and (001) planes.

[0105] The structure of the two-dimensional perovskite is that a (100) plane of a three-dimensional perovskite is sandwiched between two organic molecules, so the hole mobility of the two-dimensional perovskite is slightly lower than that of the three-dimensional perovskite, about 10 cm 2 / (V·s), but still much higher than the hole mobility (about 10 -3 cm 2 / (V·s)) of the conventional organic hole transport material, thereby effectively improving the brightness of the light-emitting diode.

[0106] Secondly, the two-dimensional perovskite has a spontaneous quantum well structure, so it has a deeper HOMO energy level, which is beneficial to the energy level matching in the device, further improves the hole injection capacity, and realizes better carrier injection balance.

[0107] According to the embodiment of the present application, the step S200 specifically comprises:

[0108] S201: dissolving one of phenylethylamine lead chloride, phenylethylamine lead bromide or phenylethylamine lead iodide in dimethyl sulfoxide (DMSO) to form a first mixed solution;

[0109] S202: spin-coating the first mixed solution on the organic hole transport layer 30;

[0110] S203: performing thermal annealing on the first mixed solution in a glove box under a nitrogen atmosphere to obtain the two-dimensional perovskite hole transport layer 40;

[0111] According to an embodiment of the present application, the concentration of lead ions in the mixed solution in S201 is between 0.15M and 0.25M.

[0112] According to an embodiment of the present application, S202 specifically includes spin-coating the mixed solution on the organic hole transport layer 30 and performing thermal annealing in a glove box filled with high-purity nitrogen, wherein the content of water and oxygen in the glove box is less than 0.1ppm, the annealing temperature is between 80 and 100℃, and the annealing time is between 10 and 30min.

[0113] According to an embodiment of the present application, step S400 specifically includes:

[0114] S401: dissolving polyvinylpyrrolidone in chlorobenzene to form a second mixed solution;

[0115] S402: spin-coating the mixed solution on the surface of the two-dimensional perovskite hole transport layer 40 to obtain the spacer layer 50.

[0116] According to an embodiment of the present application, S401 specifically includes dissolving the spacer layer 50 material polyvinylpyrrolidone (PVP) with a molecular weight of 30000 to 55000g / mol in chlorobenzene at a concentration of 2mg / ml to form the mixed solution.

[0117] According to an embodiment of the present application, step S500 specifically includes:

[0118] S501: preparing a quasi-two-dimensional perovskite;

[0119] S502: spin-coating the quasi-two-dimensional perovskite on the spacer layer 50;

[0120] S503: dropping chlorobenzene during the spin-coating process;

[0121] S504: performing thermal annealing on the quasi-two-dimensional perovskite in a glove box under a nitrogen atmosphere to obtain the perovskite light-emitting layer 60.

[0122] According to an embodiment of the present application, step S501 specifically includes:

[0123] dissolving phenethylamine iodide (PEAI), cesium iodide (Csl) and lead iodide (Pbl2) in a dimethyl sulfoxide solution to obtain a third mixed solution;

[0124] The third mixed solution is stirred at room temperature, and after the precipitates in the third mixed solution are completely precipitated, a supernatant and a lower layer precipitate are obtained.

[0125] The supernatant is filtered to obtain a quasi-two-dimensional perovskite.

[0126] According to an embodiment of the present application, in step S501, phenethylamine iodide (PEAI), cesium iodide (Csl) and lead iodide (PbI2) are dissolved in a dimethyl sulfoxide (DMSO) solution according to a molar ratio of 4:3:4.

[0127] According to an embodiment of the present application, in step S501, the concentration of Pb ions is between 0.45 and 0.55 M, and Csl is in excess according to a molar ratio of 1.5:1.

[0128] According to an embodiment of the present application, in step S501, the precipitates in the third mixed solution are impurities introduced in the process of configuring the solution.

[0129] A 0.45 μm filter is used to filter the supernatant to remove impurities in the supernatant, thereby obtaining a clean quasi-two-dimensional perovskite solution.

[0130] According to an embodiment of the present application, S502 specifically includes spin coating the quasi-two-dimensional perovskite of the perovskite light-emitting layer 60 on a polyvinylpyrrolidone (PVP) of the spacer layer 50 at a rotation speed of 6000 revolutions per minute (rpm) for 1 minute, and dropping chlorobenzene on the film for extraction at 15 s to make the quasi-two-dimensional perovskite crystallize quickly, thereby obtaining a quasi-two-dimensional perovskite film with good crystallization quality and high density.

[0131] According to an embodiment of the present application, S504 specifically includes performing thermal annealing on the perovskite light-emitting layer 60 in a glove box filled with high-purity nitrogen, wherein the content of water and oxygen in the glove box is less than 0.1 ppm, the annealing temperature is between 70 and 90 ℃, and the annealing time is between 10 and 30 minutes.

[0132] The technical solutions of the present application are described in detail below by preferred embodiments. It should be noted that the specific embodiments below are only used for illustration and do not limit the present application.

[0133] Embodiment 1: Preparation of a sample.

[0134] The substrate 10 of glass and the transparent conductive electrode 20 of indium tin oxide (ITO) are sequentially ultrasonically cleaned with a cleaning solution, acetone, isopropyl alcohol, ethanol, etc., the patterned transparent conductive electrode 20 is an anode of a light-emitting diode, and the sheet resistance thereof is about 15 ohms per square (Ω / □).

[0135] The sheet resistance is also called the thin layer resistance, which is defined as the resistance of a square semiconductor thin layer in the current direction, and the unit is ohms per square.

[0136] A layer of m-PEDOT:PSS is spin-coated on the cleaned transparent conductive electrode 20 as an organic hole transport layer 30 for hole transport. The m-PEDOT:PSS is prepared by mixing PEDOT:PSS and PSS-Na aqueous solution with a certain volume ratio, and then annealed on a hot plate with a temperature of 140-160°C for 15-20 minutes. The thickness of the organic hole transport layer 30 is 30-50 nm:

[0137] A layer of PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 is spin-coated on the organic hole transport layer 30 as a two-dimensional perovskite hole transport layer 40. The annealing is performed in a glove box filled with high-purity nitrogen with a water and oxygen content of less than 0.1 ppm, at a temperature of 80-100°C for 10-30 minutes. The thickness of the two-dimensional perovskite hole transport layer 40 is 20-40 nm:

[0138] A layer of organic polymer polyvinylpyrrolidone (PVP) is spin-coated on the two-dimensional perovskite hole transport layer 40 as a spacer layer 50. The molecular weight of PVP is 30000-55000 g / mol, and the thickness is 1-3 nm. The next step is directly performed without annealing;

[0139] A previously prepared quasi-two-dimensional perovskite (PEA2(CsPbI3)PbI4) solution is spin-coated on the surface of the spacer layer 50 to prepare a perovskite light-emitting layer 60. The rotation speed is 6000 rpm, and the spin-coating time is 1 minute. Chlorobenzene is dropped on the film for extraction at 15 s to make it crystallize quickly, so as to obtain a quasi-two-dimensional perovskite film with good crystalline quality and high density. After spin-coating, the annealing is performed in a glove box filled with high-purity nitrogen with a water and oxygen content of less than 0.1 ppm, at an annealing temperature of 70-90°C for 10-30 minutes. The prepared perovskite light-emitting layer 60 has a thickness of 30-60 nm;

[0140] The wafer with the spin-coated perovskite light-emitting layer 60 is placed in a thermal evaporation chamber, and 3TPYMB or PO-T2T or TPBi is evaporated on the wafer to a thickness of 30-50 nm under a pressure of 2×10 -4 A 1 nm layer of LiF is evaporated on the wafer in the evaporation chamber after replacing the mask, as an electron transport layer 70.

[0141] Aluminum is evaporated on the electron transport layer 70 to a thickness of 80-120 nm as a metal conductive electrode 80.

[0142] After taking the above prepared device out of the evaporation chamber, the part of the material on the transparent conductive electrode 20 is scraped off with a blade, and part of the width is removed to expose the transparent conductive electrode 20 for testing, and sample 1, sample 2 and sample 3 with PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 two-dimensional perovskite hole transport layer 40 are obtained respectively.

[0143] Example 2: Detection of samples.

[0144] Figure 3 The current density and voltage relationship curve of PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or traditional organic hole transport material TFB at the two-dimensional perovskite hole transport layer 40 of the embodiment of the application.

[0145] Figure 4 The luminance and voltage relationship curve of PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or traditional organic hole transport material TFB at the two-dimensional perovskite hole transport layer 40 of the embodiment of the application.

[0146] Figure 5 The external quantum efficiency and current density relationship curve of PEA2PbCl4, PEA2PbBr4, PEA2PbI4 or traditional organic hole transport material TFB at the two-dimensional perovskite hole transport layer 40 of the embodiment of the application.

[0147] The sample 1, sample 2 and sample 3 with PEA2PbCl4, PEA2PbBr4 or PEA2PbI4 two-dimensional perovskite hole transport layer 40 prepared in Example 1 are taken as the experimental group, and the device prepared by the traditional organic transport layer TFB is taken as the control group, and the effect of current density and voltage on the above samples is determined, and the results are shown in Figure 3 、 Figure 4 and Figure 5

[0148] As shown in Figure 3 、 Figure 4 and Figure 5 , it can be shown that the current injection in the device composed of the traditional organic transport layer material TFB is poor, resulting in low brightness of the device, while the hole mobility of the two-dimensional perovskite is high, which is beneficial to the current injection of the device, so the brightness of the device is high, and the deeper HOMO energy level is beneficial to the energy level matching of the device, further improving the hole injection ability, realizing better carrier injection balance, and improving the external quantum efficiency of the device from 5.4% to 8.1%.

[0149] ​The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above-described is only a specific embodiment of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A perovskite light-emitting diode, comprising: Substrate; A transparent conductive electrode is disposed on the substrate; An organic hole transport layer is disposed on the transparent conductive electrode and covers a portion of the transparent conductive electrode, leaving another portion of the transparent conductive electrode exposed. A two-dimensional perovskite hole transport layer is provided on top of the organic hole transport layer, wherein the material of the two-dimensional perovskite hole transport layer is one of phenylethylamine lead chloride, phenylethylamine lead bromide, or phenylethylamine lead iodine. A spacer layer covers the two-dimensional perovskite hole transport layer; A perovskite light-emitting layer covers the spacer layer; An electron transport layer covers the perovskite luminescent layer; A metallic conductive electrode, covering the electron transport layer, comprises N spaced-apart electrode units, where N is a positive integer.

2. The perovskite light-emitting diode according to claim 1, wherein, The organic hole transport layer is an aqueous solution of sodium polystyrene sulfonate in the form of a polymer of 3,4-ethylenedioxythiophene and polystyrene sulfonate, and the thickness of the organic hole transport layer is 30 nm to 50 nm.

3. The perovskite light-emitting diode according to claim 1, wherein, The transparent conductive electrode is made of indium tin oxide (ITO). The electron transport layer is made of one of the following materials: tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene or 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazole, mixed with lithium fluoride, and the thickness of the electron transport layer is 30 nm to 50 nm. The thickness of the metal conductive electrode is 80 nm to 120 nm.

4. The perovskite light-emitting diode according to claim 1, wherein, The spacer layer is made of polyvinylpyrrolidone with a molecular weight of 30,000 to 55,000 g / mol; The thickness of the spacer layer is 1 nm to 3 nm.

5. The perovskite light-emitting diode according to claim 1, wherein, The thickness of the two-dimensional perovskite hole transport layer is 20 nm to 40 nm. The perovskite luminescent layer is made of quasi-two-dimensional perovskite, and the thickness of the perovskite luminescent layer is 30 nm to 60 nm.

6. A method for manufacturing a perovskite light-emitting diode according to any one of claims 1-5, comprising: A transparent conductive electrode is fabricated on the substrate; The organic hole transport layer is spin-coated onto the transparent conductive electrode and then annealed. The two-dimensional perovskite hole transport layer was prepared by spin-coating onto the organic hole transport layer and then annealed. A spacer layer is spin-coated onto the two-dimensional perovskite hole transport layer; The perovskite light-emitting layer is spin-coated onto the spacer layer and then annealed. An electron transport layer is deposited on the perovskite light-emitting layer; Metal conductive electrodes are deposited on the electron transport layer; The organic hole transport layer covers a portion of the transparent conductive electrode, and the organic hole transport layer is removed from another portion of the transparent conductive electrode, exposing the other portion of the transparent conductive electrode.

7. The method for fabricating a perovskite light-emitting diode according to claim 6, wherein, The preparation of the two-dimensional perovskite hole transport layer by spin-coating on the organic hole transport layer, followed by annealing, includes: Dissolve one of phenethylamine lead chloride, phenethylamine lead bromide, or phenethylamine lead iodide in dimethyl sulfoxide to form a first mixed solution; Spin-coat the first mixed solution onto the organic hole transport layer; The first mixed solution was thermally annealed in a glove box under a nitrogen atmosphere to obtain the two-dimensional perovskite hole transport layer. The concentration of lead ions in the mixed solution is between 0.15M and 0.25M.

8. The method for fabricating a perovskite light-emitting diode according to claim 6, wherein, The spin-coating of the spacer layer onto the two-dimensional perovskite hole transport layer includes: Polyvinylpyrrolidone is dissolved in chlorobenzene to form a second mixed solution; The second mixed solution is spin-coated onto the surface of the two-dimensional perovskite hole transport layer to obtain the spacer layer.

9. The method for fabricating a perovskite light-emitting diode according to claim 6, wherein, The process of spin-coating a perovskite light-emitting layer onto the spacer layer and annealing includes: Preparation of quasi-two-dimensional perovskites; The quasi-two-dimensional perovskite was spin-coated onto the spacer layer; Chlorobenzene is added dropwise during the spin coating process; The quasi-two-dimensional perovskite was thermally annealed in a glove box under a nitrogen atmosphere to obtain the perovskite luminescent layer.

10. The method for fabricating a perovskite light-emitting diode according to claim 9, wherein, The preparation of the quasi-two-dimensional perovskite includes: Phenethylamine iodide, cesium iodide, and lead iodide were dissolved in dimethyl sulfoxide solution to obtain a third mixed solution; The third mixed solution was stirred at room temperature and allowed to stand until the precipitate in the third mixed solution was completely precipitated, resulting in a clear surface liquid and a lower precipitate. The quasi-two-dimensional perovskite was obtained by filtering the surface clear liquid.

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