Perovskite light emitting diode based on PVP interface modification layer and preparation method thereof

Abstract

The invention discloses a perovskite light-emitting diode based on a PVP interface modification layer and a preparation method of the perovskite light-emitting diode, and the PVP modification layer with an interface regulation and control function is introduced between a hole injection layer and a perovskite light-emitting layer, so that the crystallization quality and the interface stability of a thin film are remarkably improved. The interface modification layer not only optimizes the hydrophobicity of the surface of the substrate and promotes uniform film formation of a precursor solution and ordered growth of crystal grains, but also effectively passivates interface defects, inhibits acid erosion, and greatly improves the luminous efficiency and the service life of the luminescent device. The preparation method provided by the invention is simple in process and low in cost, has a remarkable application value, and meets the requirements of the current field of photoelectric devices on industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite light-emitting diodes, and in particular to a perovskite light-emitting diode based on a PVP interface modification layer and a preparation method thereof. Background Art

[0002] Perovskite materials have been widely used in optoelectronic devices such as solar cells and light-emitting diodes (LEDs) due to their excellent optoelectronic properties. However, the stability and performance of perovskite films are limited by defects and interface mismatches formed during their preparation, resulting in low device efficiency and shortened life. In perovskite optoelectronic devices, the choice of hole injection layer (HIL) is crucial to device performance. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is often used as HIL due to its good conductivity and transparency. However, the hydrophilicity and surface roughness of PEDOT:PSS may cause uneven crystallization when perovskite films grow on it, increase defect density, and reduce device performance. In addition, the acidity of PEDOT:PSS may corrode the perovskite light-emitting layer, further affecting the stability of the device.

[0003] In order to solve the above problems, researchers have tried to introduce an interface modification layer on the PEDOT:PSS substrate. However, some interface modification layer materials may be incompatible with PEDOT:PSS or perovskite, resulting in poor interface contact or the introduction of new defects. In addition, the preparation of some interface modification layers requires complex process steps, which increases production costs and is not conducive to large-scale production. Therefore, it is urgent to find a simple and efficient interface modification layer material and introduction method to significantly improve the quality of perovskite films and device performance. Summary of the invention

[0004] In order to solve the above technical problems, the primary purpose of the present invention is to provide a perovskite light-emitting diode based on a PVP interface modification layer and a preparation method thereof. The PVP interface modification layer is introduced into the perovskite light-emitting diode, which optimizes charge injection, improves interface stability, and effectively reduces the effect of the acidity of PEDOT:PSS on the perovskite light-emitting layer, thereby improving the environmental stability, luminous efficiency and service life of the device.

[0005] The present invention is achieved through the following technical solutions:

[0006] A perovskite light-emitting diode based on a PVP interface modification layer comprises an anode substrate, a hole injection layer, a PVP interface modification layer, a perovskite light-emitting layer, an electron injection layer, an intermediate layer and a cathode electrode which are sequentially arranged on one side of the anode substrate, wherein the material of the hole injection layer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS), and the material of the PVP interface modification layer is polyvinyl pyrrolidone (PVP), and the molecular weight of the polyvinyl pyrrolidone is 20000-30000.

[0007] The PVP interface modification layer provided by the present invention is between the hole injection layer and the perovskite light-emitting layer (i.e., the perovskite film). As a non-ionic polymer, PVP has good film-forming properties and chemical stability, can improve the physical and chemical properties of the substrate surface, form a smooth transition interface between PEDOT:PSS and the perovskite light-emitting layer, reduce interface defects, promote uniform nucleation and growth of the perovskite film, and improve the film quality. In addition, the hydrophobicity of PVP helps to increase the contact angle of the substrate and promote the uniform spreading and film formation of the perovskite precursor solution on the substrate.

[0008] Compared with other commonly used hole injection layers (such as NiO x Compared with PTAA or PTAA, the performance improvement of PVP interface modification layer on PEDOT:PSS is more obvious. x On the substrate, due to the different surface chemical properties, the modification effect of PVP is limited to physical hydrophobicity regulation, but lacks significant acid neutralization effect; on the PTAA substrate, due to its relatively hydrophobic nature, the PVP modification layer mainly improves the crystal uniformity but the gain effect is limited. Therefore, the present invention introduces a PVP interface modification layer on PEDOT:PSS, giving full play to the synergistic advantages of the two, not only effectively passivating interface defects, significantly improving the quality of the perovskite film, but also greatly improving the photoelectric performance and stability of the device, showing an effect superior to other hole injection layers.

[0009] Furthermore, the material of the electron injection layer is 4,7-diphenyl-1,10-phenanthroline (Bphen), the material of the intermediate layer is lithium fluoride (LiF), and the cathode electrode includes a silver (Ag) electrode.

[0010] A method for preparing the above-mentioned perovskite light-emitting diode based on the PVP interface modification layer comprises the following steps:

[0011] S1. Preparing a hole injection layer on an anode substrate;

[0012] S2. Preparing a PVP interface modification layer on the hole injection layer described in S1;

[0013] S3. Preparing a perovskite light-emitting layer on the PVP interface modification layer described in S2;

[0014] S4. Preparing an electron injection layer on the perovskite light-emitting layer described in S3;

[0015] S5. An intermediate layer and a cathode electrode are sequentially prepared on the electron injection layer described in S4 to obtain the perovskite light-emitting diode based on the PVP interface modification layer.

[0016] The PVP interface modification layer provided by the present invention can improve the crystallinity of the film, and as a crystal nucleus template, can promote the orderly growth of perovskite grains, reduce grain boundary defects, enhance interface stability, reduce the acidity of the hole injection layer from corroding the perovskite light-emitting layer, and improve the stability of the device. The preparation method provided by the present invention is simple and easy, low in cost, and feasible for large-scale production.

[0017] Furthermore, in step S1, the anode substrate includes an indium tin oxide (ITO) substrate.

[0018] In a specific implementation, the ITO substrate is cleaned, dried, and subjected to plasma treatment to remove impurities on the surface.

[0019] Furthermore, in step S1, the hole injection layer solution is spin-coated on the anode substrate, and the hole injection layer is obtained after annealing.

[0020] Furthermore, the spin coating speed is 4000-5000 rpm, the spin coating time is 30-40 s, the annealing temperature is 140-150° C., and the annealing time is 15-20 min.

[0021] Furthermore, in step S2, the preparation of the PVP interface modification layer comprises the following steps: coating a polyvinyl pyrrolidone solution on the hole injection layer, wherein the concentration of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution is 0.04-0.12 mg / mL, preferably 0.07-0.09 mg / mL.

[0022] When the concentration of PVP solution is too high, it affects the transmission of carriers inside the device; when the concentration is too low, the interface modification layer formed is uneven, which affects the film formation of perovskite film.

[0023] Furthermore, the preparation method of the polyvinyl pyrrolidone solution is: dissolving polyvinyl pyrrolidone in an organic solvent to obtain the polyvinyl pyrrolidone solution.

[0024] Furthermore, the organic solvent is N,N-dimethylformamide (DMF).

[0025] Furthermore, in step S2, a polyvinyl pyrrolidone solution is spin-coated on the hole injection layer, and the PVP interface modification layer is obtained after annealing.

[0026] Furthermore, the spin coating speed is 5500-6000 rpm, the spin coating time is 30-40 s, the annealing temperature is 100-110° C., and the annealing time is 5-8 min.

[0027] Furthermore, in step S3, the preparation of the perovskite light-emitting layer includes the following steps: cesium bromide (CsBr) and lead bromide (PbBr 2 ) is dissolved in an organic solvent to react to obtain a perovskite precursor (CsPbBr 3 ) solution; coating the perovskite precursor solution on the PVP interface modification layer.

[0028] Furthermore, the organic solvent is dimethyl sulfoxide (DMSO).

[0029] Furthermore, the CsBr and PbBr 2 The molar ratio is (1-1.5):1.

[0030] Furthermore, the organic solvent contains CsBr and PbBr 2 The total concentration is 100-150 mg / mL.

[0031] Furthermore, an additive may be added to the organic solvent, and the additive is polyethylene glycol (PEG) or methoxy polyethylene glycol (mPEG).

[0032] Furthermore, the concentration of the additive in the organic solvent is 3-5 mg / mL, which can make the perovskite grains uniform and reduce interface defects.

[0033] Furthermore, in step S3, the perovskite precursor solution is spin-coated on the PVP interface modification layer, and the perovskite light-emitting layer is obtained after annealing.

[0034] Furthermore, the spin coating speed is 1500-2000 rpm, the spin coating time is 60-70 s, the annealing temperature is 80-90° C., and the annealing time is 8-10 min.

[0035] Furthermore, in step S4, the electron injection layer is prepared by spin coating, the spin coating speed is 2000-3000 rpm, and the spin coating time is 40-50 s.

[0036] Furthermore, in step S5, the intermediate layer and the cathode electrode are prepared in sequence by thermal evaporation deposition.

[0037] Furthermore, the thickness of the hole injection layer is 20-30 nm, the thickness of the PVP interface modification layer is 10-20 nm, the thickness of the perovskite light-emitting layer is 100-200 nm, the thickness of the electron injection layer is 20-30 nm, the thickness of the intermediate layer is 1-5 nm, and the thickness of the cathode electrode is 100-110 nm.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention aims to provide a method for introducing a PVP interface modification layer on a hole injection layer PEDOT:PSS to improve the growth and performance of a perovskite film, enhance the crystallization quality and optoelectronic performance of the film, and enhance the stability of the device. By spin coating a layer of PVP solution on PEDOT:PSS, a uniform PVP interface modification layer is formed, the hydrophobicity of the substrate is improved, and the uniform spreading and film formation of the perovskite precursor solution on the substrate are promoted. The PVP interface modification layer can also serve as a crystal nucleus template to promote the orderly growth of perovskite grains, reduce grain boundary defects, and improve the crystallinity of the film. In addition, the PVP interface modification layer reduces the erosion of the acidity of PEDOT:PSS on the perovskite light-emitting layer, thereby improving the stability of the device.

[0040] The present invention successfully improves the growth environment of the perovskite film, improves the crystal quality and optoelectronic performance of the film, and enhances the stability of the device. The preparation method provided by the present invention has simple process, low cost, significant application value, and meets the current demand for industrialized production in the field of optoelectronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Graphs of water contact angles of the PEDOT:PSS layer in Example 1 and the PEDOT:PSS layer with a PVP interface modification layer; wherein (a) is the PEDOT:PSS layer, and (b) is the PEDOT:PSS layer with a PVP interface modification layer.

[0042] Figure 2 is CsPbBr in Example 1 and Comparative Example 1 3 XRD patterns of the layers.

[0043] Figure 3 is CsPbBr in Example 1 and Comparative Example 1 3 TRPL decay curve of the layer.

[0044] Figure 4 is CsPbBr in Example 1 and Comparative Example 1 3 PL curve of the layer.

[0045] Figure 5This is a JVL curve diagram of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1-3.

[0046] Figure 6 This is a JVL curve diagram of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1 and the perovskite light-emitting diode prepared in Comparative Example 1.

[0047] Figure 7 This is a CE-V curve of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1-3.

[0048] Figure 8 CE-V curves of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1 and the perovskite light-emitting diode prepared in Comparative Example 1.

[0049] Fig. 9 This is an EL spectrum curve of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1-3.

[0050] Fig.10 EL spectrum curves of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1 and the perovskite light-emitting diode prepared in Comparative Example 1.

[0051] Fig.11 This is a brightness attenuation curve diagram of the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1 and the perovskite light-emitting diode prepared in Comparative Example 1. DETAILED DESCRIPTION

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0053] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0054] The experimental methods used in the following examples are conventional methods unless otherwise specified, and the materials and reagents used are commercially available unless otherwise specified. PEDOT:PSS was purchased from Heraeus, model number Clevious P VPAl 4083.

[0055] The molecular weight of polyvinyl pyrrolidone in the following examples and comparative examples is 25,000.

[0056] All measurements in the following test examples were performed at room temperature and without additional packaging.

[0057] Example 1

[0058] A perovskite light-emitting diode based on PVP interface modification layer ITO / PEDOT:PSS / PVP / CsPbBr 3 / Bphen / LiF / Ag, comprising an ITO substrate, a PEDOT:PSS layer, a PVP interface modification layer, a CsPbBr 3 The layer, Bphen layer, LiF layer and Ag electrode are prepared by the following method:

[0059] S1. Prepare a 25nm PEDOT:PSS layer on an ITO substrate: Use glass cleaner, deionized water and alcohol to clean the ITO substrate, ultrasonically clean it for at least 30 minutes in each step, then blow dry the surface of the ITO substrate with nitrogen, and treat it with plasma for 90 seconds to remove surface impurities. Spin coat the PEDOT:PSS solution on the clean ITO substrate at a speed of 4000rpm for 40 seconds, anneal at 150°C for 15 minutes to remove the solvent residue, and obtain a PEDOT:PSS layer.

[0060] S2. Prepare a 15 nm PVP interface modification layer on the PEDOT:PSS layer described in S1: dissolve PVP in DMF, stir at room temperature for 12 hours to obtain a 0.08 mg / mL PVP solution, spin coat the PVP solution on the PEDOT:PSS layer at a rotation speed of 6000 rpm for 30 seconds, and anneal at 100°C for 5 minutes to obtain the PVP interface modification layer.

[0061] S3. Preparation of 150 nm CsPbBr on the PVP interface modification layer described in S2 3 Layer: CsBr, PbBr 2 and PEG were dissolved in DMSO, where CsBr and PbBr 2 The molar ratio of CsBr and PbBr is 1.1:1. 2 The total concentration of 100 mg / mL and the concentration of PEG were 3 mg / mL, and stirred on a heating plate at 60 °C for at least 3 hours to prepare CsPbBr 3 Precursor solution. Preparation of CsPbBr by one-step spin coating on PVP interface modification layer 3 Layer, add 70 μL CsPbBr 3The precursor solution was dropped onto the PVP interface modification layer, and spin coating was started immediately without standing. The speed was 1500 rpm, the spin coating was performed for 70 seconds, and the annealing treatment was performed at 80 °C for 10 minutes to promote the growth of perovskite crystals to obtain CsPbBr 3 layer.

[0062] S4. CsPbBr as described in S3 3 Prepare a 25 nm Bphen layer on the CsPbBr layer: Dissolve Bphen in chlorobenzene and stir at room temperature for more than one hour to fully dissolve it to prepare a 10.7 mg / mL Bphen solution. 3 50 μL of Bphen solution was dropped onto the CsPbBr layer and spin coated at 2000 rpm for 40 s. 3 A Bphen layer was deposited on the layer and then placed in a glove box for 10 min.

[0063] S5. Sequentially prepare a LiF layer and an Ag electrode on the Bphen layer described in S4: under vacuum conditions (about 4×10 -4 Pa), a 1nm LiF layer and a 100nm Ag electrode were prepared in sequence by thermal evaporation deposition to obtain a perovskite light-emitting diode based on a PVP interface modification layer.

[0064] Example 2

[0065] A perovskite light-emitting diode based on PVP interface modification layer ITO / PEDOT:PSS / PVP / CsPbBr 3 / Bphen / LiF / Ag, comprising an ITO substrate, a PEDOT:PSS layer, a PVP interface modification layer, a CsPbBr 3 The preparation method of the Ag electrode is basically the same as that of Example 1, except that in step S2, the concentration of the PVP solution is 0.04 mg / mL.

[0066] Example 3

[0067] A perovskite light-emitting diode based on PVP interface modification layer ITO / PEDOT:PSS / PVP / CsPbBr 3 / Bphen / LiF / Ag, comprising an ITO substrate, a PEDOT:PSS layer, a PVP interface modification layer, a CsPbBr 3 The preparation method of the Ag electrode is basically the same as that of Example 1, except that in step S2, the concentration of the PVP solution is 0.12 mg / mL.

[0068] Comparative Example 1

[0069] A perovskite light-emitting diode ITO / PEDOT:PSS / CsPbBr 3 / Bphen / LiF / Ag, comprising an ITO substrate, a PEDOT:PSS layer, a CsPbBr 3 The layer, Bphen layer, LiF layer and Ag electrode are prepared by the following method:

[0070] S1. Prepare a 25nm PEDOT:PSS layer on an ITO substrate: Use glass cleaner, deionized water and alcohol to clean the ITO substrate, ultrasonically clean it for at least 30 minutes in each step, then blow dry the surface of the ITO substrate with nitrogen, and treat it with plasma for 90 seconds to remove surface impurities. Spin coat the PEDOT:PSS solution on the clean ITO substrate at a speed of 4000rpm for 40 seconds, anneal at 150°C for 15 minutes to remove the solvent residue, and obtain a PEDOT:PSS layer.

[0071] S2. Prepare 150nm CsPbBr on the PEDOT:PSS layer described in S1 3 Layer: CsBr, PbBr 2 and PEG were dissolved in DMSO, where CsBr and PbBr 2 The molar ratio of CsBr and PbBr is 1.1:1. 2 The total concentration of 100 mg / mL and the concentration of PEG were 3 mg / mL, and stirred on a heating plate at 60 °C for at least 3 hours to prepare CsPbBr 3 Precursor solution. Preparation of CsPbBr by one-step spin coating on PEDOT:PSS layer 3 Layer, add 70 μL CsPbBr 3 The precursor solution was dropped onto the PEDOT:PSS layer and spin-coated immediately without standing. The speed was 1500 rpm for 70 seconds and annealed at 80°C for 10 minutes to promote the growth of perovskite crystals to obtain CsPbBr 3 layer.

[0072] S3. CsPbBr as described in S2 3 Prepare a 25 nm Bphen layer on the CsPbBr layer: Dissolve Bphen in chlorobenzene and stir at room temperature for more than one hour to fully dissolve it to prepare a 10.7 mg / mL Bphen solution. 3 50 μL of Bphen solution was dropped onto the CsPbBr layer and spin coated at 2000 rpm for 40 s. 3 A Bphen layer was deposited on the layer and then placed in a glove box for 10 min.

[0073] S4. Sequentially prepare a LiF layer and an Ag electrode on the Bphen layer described in S3: under vacuum conditions (about 4×10 -4 Pa), and a 1nm LiF layer and a 100nm Ag electrode were prepared in sequence by thermal evaporation deposition to obtain a perovskite light-emitting diode.

[0074] Test Case

[0075] The water contact angles of the PEDOT:PSS layer in Example 1 and the PEDOT:PSS layer with a PVP interface modification layer were tested. The test results are shown in FIG. Figure 1 As shown in the figure, the water contact angle of the PEDOT:PSS layer is 53.9°, and the water contact angle after adding the PVP interface modification layer is 62.9°. The higher contact angle indicates that the hydrophobicity of the substrate is enhanced, which helps to form a perovskite film with larger grains and reduce defects at the grain boundaries.

[0076] For CsPbBr in Example 1 and Comparative Example 1 3 The layer was subjected to X-ray diffraction (XRD) analysis, and the analysis results were as follows Figure 2 As shown in the figure, the introduction of the PVP interface modification layer increases the diffraction peak intensity of the perovskite film on the (110) crystal plane and reduces the half-height width. This indicates that the crystallinity of the perovskite film is improved, the grain size is increased, and the grain boundary defects are reduced, which is conducive to the radiative recombination of carriers in the light-emitting layer.

[0077] For CsPbBr in Example 1 and Comparative Example 1 3 The transient fluorescence (TRPL) decay test is performed on the layer. The test results are as follows Figure 3 As shown, the carrier lifetime of the perovskite film with the PVP interface modification layer increased from 21.8 ns in comparative example 1 to 37.5 ns. The extension of the carrier lifetime indicates that non-radiative recombination is reduced, the film quality is improved, and it is beneficial to improve the luminous efficiency of the device.

[0078] For CsPbBr in Example 1 and Comparative Example 1 3 The photoluminescence (PL) test was performed on the layer, and the test results were as follows Figure 4 As shown in the figure, the introduction of the PVP interface modification layer increases the PL intensity and keeps the luminescence peak stable. The higher PL intensity indicates that the introduction of the PVP interface modification layer effectively passivates the interface defects and reduces the non-radiative recombination, thereby significantly improving the radiative recombination efficiency and optical quality of the film. The higher PL intensity further reflects the improvement of the exciton emission efficiency, indicating that the perovskite light-emitting layer is more efficient in converting the injected charge carriers into photons, which has a positive effect on improving the current efficiency (CE) and brightness of the light-emitting device.

[0079] The perovskite light-emitting diodes based on the PVP interface modification layer prepared in Examples 1-3 and the perovskite light-emitting diode prepared in Comparative Example 1 were tested for current density-voltage-brightness (JVL) performance. The test results are as follows: Figure 5 and Figure 6 As shown in the figure, the current density of the perovskite light-emitting diode of Example 1 is significantly higher than that of Comparative Example 1, especially at the same voltage, indicating that the PVP interface modification layer improves the charge injection and transfer efficiency, and the device brightness increases from 4800.9 cd / m 2 Increased to 17782cd / m 2 The perovskite light-emitting diode based on the PVP interface modification layer of Example 1 of the present invention has a lower turn-on voltage, and the V on The drop from 2.8V to 2.6V is related to the optimization of interface energy level matching. PVP-modified surface can promote hole injection at the interface.

[0080] The perovskite light-emitting diodes based on the PVP interface modification layer prepared in Examples 1-3 and the perovskite light-emitting diode prepared in Comparative Example 1 were tested for current efficiency-voltage (CE-V). The test results are as follows: Figure 7 and Figure 8 As shown, after using PVP, the device efficiency of Example 1 of the present invention is improved from 0.48cd / A to 2.59cd / A. The device efficiency of the present invention is higher than that of Comparative Example 1 in the entire current density range, indicating that the interface modification significantly improves the luminous efficiency of the light-emitting layer. At low voltage, the device of the present invention exhibits higher current efficiency, indicating that PVP effectively alleviates the problem of interface charge accumulation and improves the injection of interface carriers.

[0081] The electroluminescence (EL) spectrum test was performed on the perovskite light-emitting diodes based on the PVP interface modification layer prepared in Examples 1-3 and the perovskite light-emitting diode prepared in Comparative Example 1. The test results are as follows: Fig. 9 and Fig.10 As shown, the EL peak position of the device of the present invention has no obvious shift, indicating that the PVP interface modification layer has little effect on the optical band gap of the perovskite, and its main function is interface optimization and defect passivation. In addition, there is good green light emission at 523nm, and the full width at half maximum (FWHM) of the EL spectrum is about 21.5nm.

[0082] The EL life test was carried out on the perovskite light-emitting diode based on the PVP interface modification layer prepared in Example 1 and the perovskite light-emitting diode prepared in Comparative Example 1. When the initial brightness was ~100 cd / m 2 The brightness decay curve is recorded below, such as Fig.11As shown, the EL lifetime of the device containing the PVP interface modification layer is extended from 1.06 hours in comparative example 1 to 15.56 hours. The extension of the device lifetime indicates that the PVP interface modification layer effectively improves the stability of the device and reduces interface degradation.

[0083] In summary, the present invention significantly improves the performance and stability of perovskite light-emitting diodes (PeLEDs) by introducing a PVP interface modification layer on a PEDOT:PSS substrate, and has the following advantages: 1. Improved film crystallinity: The PVP interface modification layer promotes uniform nucleation and growth of perovskite films by regulating the physical and chemical properties of the PEDOT:PSS surface, improves the crystallization quality of the film, and reduces grain boundary defects. 2. Significantly improved device performance: The PVP interface modification layer effectively passivates defects and improves carrier injection efficiency and luminescence efficiency. 3. Enhanced interface stability: The PVP interface modification layer effectively reduces the acidity of PEDOT:PSS from corroding perovskite, forms a stable interface, prolongs the working life of the device, and improves environmental tolerance. 4. Simple and economical process: The preparation method of the present invention is simple, the PVP material cost is low, and no complex equipment or process is required, and it is easy to mass produce. 5. Wide applicability: The method is applicable to a variety of perovskite light-emitting devices, including visible and near-infrared range light-emitting applications, and has strong versatility and market potential.

[0084] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A perovskite light-emitting diode based on a PVP interface modification layer, characterized in that: The invention comprises an anode substrate, a hole injection layer, a PVP interface modification layer, a perovskite light-emitting layer, an electron injection layer, an intermediate layer and a cathode electrode which are sequentially arranged on one side of the anode substrate. The material of the hole injection layer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), the material of the PVP interface modification layer is polyvinyl pyrrolidone, and the molecular weight of the polyvinyl pyrrolidone is 20000-30000.

2. The perovskite light-emitting diode based on the PVP interface modification layer according to claim 1, characterized in that: The material of the electron injection layer is 4,7-diphenyl-1,10-phenanthroline.

3. A method for preparing a perovskite light-emitting diode based on a PVP interface modification layer according to claim 1 or 2, characterized in that: The following steps are involved: S1. Preparing a hole injection layer on an anode substrate; S2. Preparing a PVP interface modification layer on the hole injection layer described in S1; S3. Preparing a perovskite light-emitting layer on the PVP interface modification layer described in S2; S4. Preparing an electron injection layer on the perovskite light-emitting layer described in S3; S5. An intermediate layer and a cathode electrode are sequentially prepared on the electron injection layer described in S4 to obtain the perovskite light-emitting diode based on the PVP interface modification layer.

4. The preparation method according to claim 3, characterized in that: In step S1, a hole injection layer solution is spin-coated on the anode substrate, and the hole injection layer is obtained after annealing.

5. The preparation method according to claim 4, characterized in that: The rotation speed of the spin coating is 4000-5000 rpm, the spin coating time is 30-40s, and the temperature of the annealing treatment is 140-150°C.

6. The preparation method according to claim 3, characterized in that: In step S2, the preparation of the PVP interface modification layer comprises the following steps: coating a polyvinyl pyrrolidone solution on the hole injection layer, wherein the concentration of the polyvinyl pyrrolidone solution is 0.04-0.12 mg / mL.

7. The preparation method according to claim 6, characterized in that: In step S2, a polyvinyl pyrrolidone solution is spin-coated on the hole injection layer, and the PVP interface modification layer is obtained after annealing.

8. The preparation method according to claim 7, characterized in that: The rotation speed of the spin coating is 5500-6000 rpm, and the spin coating time is 30-40 s.

9. The preparation method according to claim 7, characterized in that: The annealing treatment is carried out at a temperature of 100-110°C.

10. The preparation method according to claim 3, characterized in that: The preparation of the perovskite light-emitting layer comprises the following steps: dissolving cesium bromide and lead bromide in an organic solvent to react to obtain a perovskite precursor solution; and coating the perovskite precursor solution on the PVP interface modification layer.

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