A composition of a zinc-lead halide quasi-two-dimensional green light perovskite and a preparation method and application thereof

Abstract

The application discloses a kind of zinc lead halide quasi two-dimensional green light perovskite composition and its preparation method and application, the preparation raw material of the zinc lead halide quasi two-dimensional green light perovskite composition includes: [bis (4-methoxyphenyl) phosphine oxide] tert-butyl carbamate and zinc bromide.The device prepared achieves the significant improvement of external quantum efficiency (EQE) from 7.1% to 21.5%, this leap means that the great leap of device in photoelectric conversion efficiency, provides more efficient selection for the application in relevant field.Meanwhile, the T 50 The life is also prolonged from short 0.86 hours to surprising 3.72 hours, is prolonged about 4.3 times, greatly improves the durability and reliability of product.

Description

Technical Field

[0001] This invention belongs to the field of microelectronic device technology, specifically relating to a composition of zinc lead halide quasi-two-dimensional green perovskite, its preparation method, and its application. Background Technology

[0002] Lead halide perovskite light-emitting diodes (PeLEDs), as a highly promising technological innovation, are gradually demonstrating their immeasurable application potential in display technology, the lighting industry, and communications. Since their electroluminescence properties were first revealed, PeLED technology has made rapid progress, successfully achieving high-efficiency light emission in the green, red, and even near-infrared spectral ranges. This achievement has undoubtedly injected new vitality into the optoelectronic field. Especially in the field of green PeLEDs, researchers have continuously explored and innovated, proposing a series of cutting-edge strategies such as multi-ligand passivation technology, fine interface engineering, and material structure optimization, aiming to significantly improve the radiative recombination efficiency of devices. Currently, the external quantum efficiency (EQE) of green PeLEDs has exceeded 30%. This research progress not only demonstrates a major leap in the practical application of perovskite materials but also heralds the imminent opening of a new chapter in their commercial applications. However, as a key component of these high-performance materials, the environmental exposure issues of lead cannot be ignored. Lead toxicity poses a serious challenge to the nervous system, children's cognitive and growth development, kidney function, immune system, and even the potential carcinogenic risk. These environmental problems and toxicity concerns severely restrict its market promotion and commercialization as a green and environmentally friendly emerging technology. Therefore, increasing investment in the research and development of environmentally friendly perovskite materials and accelerating their industrialization process is of immeasurable value and significance for promoting the sustainable development of the global optoelectronic industry and achieving harmonious coexistence between the economy, society, and the environment.

[0003] Currently, the core challenge facing perovskite PeLEDs lies in reducing their negative environmental impact, primarily due to the potential toxicity of APbX3 compounds, which are relied upon by many high-performance devices. Research indicates that the high symmetry of the APbX3 structure is related to the Pb 6s... 2 6p 0The unique electronic configuration is the cornerstone of its superior optoelectronic performance. Specifically, the lack of significant bonding-antibonding interactions between the conduction and valence bands in APbX3 leads to most intrinsic defects forming shallow transition levels, while only a few high-formation-energy defects can trigger deeper transition levels, thus endowing the material with excellent defect resistance. Furthermore, the band edge, mainly contributed by p orbitals, exhibits a larger effective mass compared to the more delocalized s orbital band edge. However, the strong spin-orbit coupling effect in APbX3 cleverly maintains a relatively small effective mass at the conduction band edge of the Pb 6p orbital. This characteristic helps achieve efficient balanced carrier transport, which is crucial for improving the performance of optoelectronic materials. Based on these characteristics, two common strategies for achieving efficient and environmentally friendly green APbX3 structures are: one is to partially replace Pb to create low-lead perovskite, retaining the optoelectronic advantages of Pb while reducing toxicity; the other is to completely replace Pb, pursuing lead-free perovskite, but this imposes more stringent conditions on the electronic structure of the substitute element. Because devices that completely replace Pb exhibit poor performance, researchers often employ a strategy of partial Pb substitution, introducing less toxic metal ions such as tin (Sn), germanium (Ge), and antimony (Sb) to partially replace the B-site Pb ions. However, despite the promising prospects of this approach, the external quantum efficiency (EQE) of lead-free green PeLEDs is generally low, becoming a bottleneck restricting their widespread application. Therefore, improving the photoelectric properties of lead-free perovskite materials and optimizing device structure and design to overcome this technical obstacle are key issues that urgently need to be addressed in current research. According to relevant research reports, in the innovative exploration of green PeLEDs, Ge was successfully introduced as a partial substitute for Pb, significantly reducing the toxicity risk of the material. The prepared Ge-Pb perovskite thin film achieved a photoluminescence quantum yield (PLQY) as high as 71%, representing a 34% improvement in efficiency compared to unsubstituted perovskite films. Furthermore, the EQE of Ge-Pb-based PeLEDs reached 13.1%, marking a significant advancement in the field of perovskite material modification at that time. Although PeLEDs that partially replace Pb have made significant progress in terms of efficiency, stability and spectral characteristics, a series of challenges and problems still need to be overcome to further improve the efficiency and stability of perovskite LEDs. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a zinc lead halide quasi-two-dimensional green perovskite composition, and the PeLED devices prepared therefrom exhibit excellent spectral stability.

[0005] The present invention also proposes a method for preparing a composition of zinc-lead halide quasi-two-dimensional green perovskite.

[0006] The present invention also proposes a perovskite thin film prepared from the composition of the zinc-lead halide quasi-two-dimensional green perovskite.

[0007] The present invention also proposes a perovskite light-emitting diode, comprising an anode conductive glass layer, a hole transport layer, an interface modification layer, a perovskite light-emitting layer, an electron transport layer, an electron injection layer, and a cathode layer stacked sequentially, wherein the perovskite light-emitting layer is the perovskite thin film.

[0008] According to a first aspect of the present invention, a composition of zinc-lead halide quasi-two-dimensional green perovskite is provided, wherein the raw materials for preparing the composition of zinc-lead halide quasi-two-dimensional green perovskite include: tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate and zinc bromide.

[0009] According to an embodiment of the first aspect of the present invention, at least the following beneficial effects are achieved:

[0010] This invention introduces the environmentally friendly element zinc (Zn), which successfully replaces a portion of lead (Pb), thereby significantly reducing environmental pollution during the production process. Furthermore, by innovatively incorporating the additive tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate (BPCA, CAS: 619333-95-8), not only is the overall performance of the device effectively enhanced, but a qualitative leap is achieved in several key indicators. Compared with industry benchmark research (Nat. Commun. 2021, 12, 4295), the significant advantage of this invention lies in the selection of Zn, which is more abundant and less expensive, as a substitute material. Compared to the traditionally used germanium (Ge), this shift not only reduces production costs but also broadens the diversity of material sources. More importantly, the zinc-to-lead substitution ratio has been significantly increased from 10% to 15%, demonstrating higher environmental benefits and substitution potential. In terms of performance, this invention achieves a significant improvement in external quantum efficiency (EQE) from 7.1% to 21.5%. This leap forward signifies a substantial increase in the device's photoelectric conversion efficiency, providing a more efficient option for applications in related fields. Simultaneously, the device's T... 50 Lifespan (the time required for brightness to drop to 50% of initial brightness) has also been extended from a mere 0.86 hours to an impressive 3.72 hours, an increase of approximately 4.3 times, significantly improving the product's durability and reliability. Furthermore, the repeatability of this invention has been significantly enhanced, ensuring the stability of the production process and the consistency of product quality, laying a solid foundation for large-scale commercial application.

[0011] In some embodiments of the present invention, the raw materials for preparing the zinc-lead halide quasi-two-dimensional green perovskite composition further include: cesium bromide, lead bromide, zinc bromide, and phenylbutylamine bromide.

[0012] In some embodiments of the present invention, the molar ratio of cesium bromide, lead bromide, zinc bromide, phenylbutylammonium bromide, and tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate is: 1–1.2: 1–x: x: 0.4–0.8: 0.1–0.5; where x is 0–30%.

[0013] According to a second aspect of the present invention, a method for preparing the zinc-lead halide quasi-two-dimensional green perovskite composition is provided, comprising the following steps: mixing cesium bromide, lead bromide, zinc bromide, phenylbutylamine bromide and tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate in solution and heating to react, thereby obtaining the composition.

[0014] In some embodiments of the present invention, the heating temperature is 30 to 60°C, and the heating time is not less than 6 hours.

[0015] In some embodiments of the present invention, Pb in the solution state 2+ With Zn 2+ The sum of their concentrations is 0.04–0.06 mol / L.

[0016] According to a second aspect of the present invention, a perovskite thin film is provided, said perovskite thin film being prepared from the composition of the zinc lead halide quasi-two-dimensional green perovskite.

[0017] According to a third aspect of the present invention, a perovskite light-emitting diode is provided, comprising an anode conductive glass layer, a hole transport layer, an interface modification layer, a perovskite light-emitting layer, an electron transport layer, an electron injection layer, and a cathode layer sequentially stacked thereon, wherein the perovskite light-emitting layer is the perovskite thin film.

[0018] In some embodiments of the present invention, the method for fabricating the perovskite light-emitting diode includes the following steps:

[0019] S1: After patterning the conductive glass using laser etching, the conductive glass is ultrasonically cleaned sequentially using acetone, ethanol and deionized water.

[0020] S2: The cleaned conductive glass is dried in an oven to obtain a conductive glass layer, and then immediately placed in an environment filled with an inert atmosphere (which can be N2);

[0021] S3: The hole transport layer solution is deposited on a conductive glass substrate by spin coating, followed by annealing to obtain the hole transport layer;

[0022] S4: The interface modification layer is deposited on the hole transport layer by vacuum evaporation to obtain an interface modification layer film.

[0023] S5: The prepared perovskite precursor solution is deposited on the electron transport layer by spin coating, followed by annealing to obtain the perovskite luminescent layer.

[0024] S6: The electron transport layer is deposited on the light-emitting layer film by vacuum evaporation to obtain the electron transport layer film;

[0025] S7: The electron injection layer is deposited on the electron transport layer film by vacuum evaporation to obtain the electron injection layer film;

[0026] S8: The metal electrode layer is deposited on the electrode modification layer film by vacuum evaporation to obtain the metal electrode.

[0027] In some embodiments of the present invention, the conductive glass substrate includes a glass substrate with an indium tin oxide (ITO) deposited on its surface.

[0028] In some embodiments of the present invention, in step S1, the ultrasonic cleaning time is not less than 10 minutes.

[0029] In some embodiments of the present invention, in step S2, the drying time is 5-30 minutes and the drying temperature is 100-150°C.

[0030] In some embodiments of the present invention, in step S3, the material of the hole transport layer includes poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine).

[0031] In some embodiments of the present invention, the concentration of poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) in solution is 4 to 8 mg / ml.

[0032] In some embodiments of the present invention, the solvent in the poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) solution is chlorobenzene.

[0033] In some embodiments of the present invention, in step S3, the spin coating parameters are: rotation speed 3000-5000 rpm, spin coating time 30-120 s.

[0034] In some embodiments of the present invention, in step S3, the annealing temperature is 100–200°C and the annealing time is 10–30 min.

[0035] In some embodiments of the present invention, in step S4, the parameters of the vacuum evaporation are: pressure of 5 × 10⁻⁶. -5 ~5×10 -4 Pa, coating thickness 1-5 nm, rate

[0036] In some embodiments of the present invention, in step S5, the spin coating speed is 3000-5000 rpm, and the spin coating time is 30-200 s.

[0037] In some embodiments of the present invention, in step S5, the annealing temperature is 60-100°C and the annealing time is 30-300s.

[0038] In some embodiments of the present invention, the material of the electron transport layer includes at least one selected from 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-o-phenanthroline, and 4-biphenyl-di(2-methyl-8-hydroxyquinoline)aluminum.

[0039] In some embodiments of the present invention, the material of the interface modification layer includes at least one of lithium fluoride and oxyacid lithium salt.

[0040] In some embodiments of the present invention, in step S6, the parameters of the vacuum evaporation are: pressure of 5 × 10⁻⁶. -5 ~5×10 -4 Pa, coating thickness of 20–50 nm, rate

[0041] In some embodiments of the present invention, the material of the electron injection layer includes lithium fluoride.

[0042] In some embodiments of the present invention, in step S7, the parameters of the vacuum evaporation are: pressure of 5 × 10⁻⁶. -4 ~8×10 -4 Pa, coating thickness of 1-2 nm, rate

[0043] In some embodiments of the present invention, in step S8, the parameters of the vacuum evaporation are: pressure of 5 × 10⁻⁶. -5 ~5×10 -4 Pa, coating thickness of 100–200 nm, rate

[0044] In some embodiments of the present invention, the method for fabricating the perovskite light-emitting diode further includes encapsulating the fabricated perovskite light-emitting diode.

[0045] In some embodiments of the present invention, the encapsulation process includes bonding the glass sheet to the obtained device with UV-curable adhesive, and then curing it by irradiating it with a 365nm UV lamp for 30-40 seconds. Attached Figure Description

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0047] Figure 1 The perovskite light-emitting diode device structure diagram prepared for the example is shown below;

[0048] Figure 2 PL spectra of the light-emitting layer films with different substitution ratios in the embodiments and comparative examples;

[0049] Figure 3 The transient fluorescence lifetime spectra of the luminescent layer films of Example 1 and Comparative Example 1 are shown.

[0050] Figure 4 PLQY statistical graphs of the light-emitting layer films of Example 1 and Comparative Example 1;

[0051] Figure 5 The current density-voltage-brightness graphs of the PeLED devices in the examples and comparative examples are shown.

[0052] Figure 6 The current density versus EQE graphs for the PeLED devices in the examples and comparative examples are shown.

[0053] Figure 7 The EL spectra of PeLED devices in the examples and comparative examples;

[0054] Figure 8 The PeLED devices of Example 1 and Comparative Example 1 were run for T 50 Lifetime diagram;

[0055] Figure 9 Two-dimensional contour pseudocolor maps of the spectral stability of PeLED devices at different voltages for the examples and comparative cases;

[0056] Figure 10 The diagram shows the PeLED current density versus external quantum efficiency (EQE) for Example 1 and Comparative Example 2. Detailed Implementation

[0057] The terms "preferred," "more preferably," etc., used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0058] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0059] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present invention.

[0060] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0061] Example 1

[0062] This embodiment provides a method for preparing a zinc-lead halide quasi-two-dimensional green perovskite composition and a perovskite light-emitting diode, specifically:

[0063] The preparation method of the zinc-lead halide quasi-two-dimensional green perovskite composition is as follows:

[0064] CsBr, PbBr, ZnBr, PBABr, and BPCA were dissolved in DMSO in a ratio of 1.15:0.85:0.15:0.5:0.2 and mixed to ensure that Pb in the precursor was present. 2+ With Zn 2+ The sum of the concentrations of the two was 0.05 mol / L. The mixed solution was then placed on a hot plate at 40°C and stirred overnight for more than 6 hours to obtain a composition of zinc lead halide quasi-two-dimensional green perovskite (perovskite precursor solution).

[0065] The fabrication method of perovskite light-emitting diodes is as follows:

[0066] S1: The bottom electrode patterning process of the ITO conductive glass substrate is performed by laser etching. The etched ITO conductive glass is ultrasonically cleaned with acetone, ethanol and deionized water for no less than 15 minutes.

[0067] S2: Dry the cleaned conductive glass substrate in an oven at 150°C for at least 10 minutes to remove moisture from the substrate surface, and then immediately transfer it into a glove box filled with inert gas (N2).

[0068] S3: Spin-coat a 4 mg / mL TFB solution onto an ITO conductive glass substrate at 3000 rpm for 30 s. Then anneal it on a 135 ℃ heating stage for 20 min. After cooling, a hole transport layer film is obtained.

[0069] S4: Place the ITO substrate coated with TFB on a surface with a pressure of 5 × 10⁻⁶. -4 ~8×10 -4 Vacuum evaporation was performed under Pa conditions using a square mask, with LiF as the evaporation material, resulting in a film thickness of 2.5 nm and a deposition rate of [missing information]. A thin film of interface modification layer was obtained;

[0070] S5: Spin-coat the perovskite precursor solution onto the interface modification layer film at a spin speed of 5000 rpm for 80 s. Immediately after spin-coating, anneal the film at a temperature of 90 ℃ for 60 s. After cooling, a zinc lead halide quasi-two-dimensional green light perovskite film is obtained.

[0071] S6: At a pressure of 5×10 -4 Evaporation was performed under Pa conditions using a square mask, with TPBi as the electron transport layer material, a film thickness of 40 nm, and a deposition rate of [missing information].

[0072] S7: At a pressure of 5×10 -4 Evaporation was performed under Pa conditions using a square mask. The electron injection layer was made of LiF, the film thickness was 1 nm, and the deposition rate was approximately [missing information].

[0073] S8: At a pressure of 5×10 -4 Evaporation was performed under Pa conditions using a strip mask, with Al as the cathode material, a film thickness of 150 nm, and a deposition rate of [missing information].

[0074] Finally, the perovskite light-emitting diodes are packaged. After bonding the glass sheet with UV-curable adhesive, they are then irradiated with a 365nm UV lamp for about 30 seconds to cure, thus completing the packaging and obtaining the perovskite light-emitting diode device.

[0075] Example 2

[0076] The difference between this embodiment and Example 1 is that the Pb substitution ratio in the perovskite luminescent layer is 10%. Specifically, CsBr, PbBr, ZnBr, PBABr and BPCA are dissolved in DMSO in a ratio of 1.15:0.9:0.1:0.5:0.2 and mixed, while the rest remain unchanged.

[0077] Example 3

[0078] The difference between this embodiment and Example 1 is that the Pb substitution ratio in the perovskite luminescent layer is 20%. Specifically, CsBr, PbBr, ZnBr, PBABr and BPCA are dissolved in DMSO in a ratio of 1.15:0.8:0.2:0.5:0.2 and mixed, while the rest remain unchanged.

[0079] Example 4

[0080] The difference between this embodiment and Example 1 is that the Pb substitution ratio in the perovskite luminescent layer is 30%. Specifically, CsBr, PbBr, ZnBr, PBABr and BPCA are dissolved in DMSO in a ratio of 1.15:0.7:0.3:0.5:0.2 and mixed, while the rest remain unchanged.

[0081] Comparative Example 1

[0082] The difference between this embodiment and Example 1 is that the Pb substitution ratio in the perovskite luminescent layer is 0. Specifically, CsBr, PbBr, ZnBr, PBABr and BPCA are dissolved in DMSO in a ratio of 1.15:1:0:0.5:0.2 and mixed, while the rest remain unchanged.

[0083] Comparative Example 2

[0084] The difference between this embodiment and Example 1 is that potassium p-aminobenzoate (CAS: 138-84-1) is used to replace bis(4-methoxyphenyl)phosphoxy[tert-butyl]carbamate in the preparation of the perovskite luminescent layer, while the rest remains unchanged.

[0085] Test case

[0086] Figure 1 This is a structural diagram of a zinc-lead halide quasi-two-dimensional green perovskite light-emitting diode device. From bottom to top, the components are: anode conductive glass, hole transport layer, interface modification layer, perovskite light-emitting layer, electron transport layer, electron injection layer, and cathode.

[0087] Figure 2The photoluminescence (PL) spectra of the luminescent layer films of Example 1 (15% substitution), Comparative Example 1 (0% substitution), Example 2 (10% substitution), Example 3 (20% substitution), and Example 4 (30% substitution) are shown. According to the test results, the photoluminescence (PL) spectra of films prepared by gradually substituting PbBr2 with ZnBr2 at different ratios showed a stable trend without significant changes. Specifically, when the substitution ratio of ZnBr2 gradually increased from 0% to 30%, the PL peak wavelength of the film only underwent a slight blue shift. Specifically, the PL peak of the unsubstituted (0% ZnBr2) film was at 505 nm, and remained at 505 nm after 10% substitution, showing good stability. When further substituted to 15%, the PL peak slightly blue-shifted to 504 nm; when the substitution ratio reached 20%, the blue shift was more pronounced, and the PL peak dropped to 503 nm; however, even when the substitution ratio increased to 30%, the PL peak slightly rebounded to 504 nm, but still did not show a significant change. In-depth analysis of this series of PL test results shows that the partial substitution of PbBr2 by ZnBr2 did not significantly affect the fluorescence properties of the film, especially in the visible light band, the fluorescence emission of the film maintained high stability and consistency.

[0088] Figure 3 The transient fluorescence lifetime spectra of the luminescent layer films of Example 1 (15% substitution) and Comparative Example 1 (0% substitution) are shown. According to the test results, the film prepared by replacing 15% of PbBr2 with ZnBr2 exhibits a significantly extended fluorescence decay lifetime. This finding directly proves that the exciton lifetime inside the substituted film is effectively extended. Specifically, the extended exciton lifetime means that excitons formed by electrons and holes can exist more stably in the film, reducing energy loss due to non-radiative recombination pathways. This improved stability directly promotes the efficiency of the radiative recombination process, allowing more excitons to release energy through luminescence rather than dissipating it as heat or other non-radiative forms. Furthermore, the extended exciton lifetime also facilitates efficient energy transport within the film. During the longer exciton lifetime, excitons have more time to migrate within the film, searching for more suitable recombination sites, thereby improving the efficiency and directionality of energy transport.

[0089] Figure 4The graph shows the photoluminescence quantum yield (PLQY) of the luminescent layer films in Example 1 (15% substitution) and Comparative Example 1 (0% substitution). According to the test results, the film prepared by replacing 15% of PbBr2 with ZnBr2 exhibits a significantly improved PLQY, specifically a PLQY as high as 92.1%, which is extremely excellent among similar materials. In contrast, the film without ZnBr2 substitution (0% substitution, i.e., PbBr2 content remains 100%) has a PLQY of only 60.5%. This stark contrast strongly illustrates that by precisely controlling the partial substitution of PbBr2 with ZnBr2 (15% in this example), not only is the luminescence efficiency of the film significantly improved, but its ability to effectively convert absorbed energy into light radiation is also greatly enhanced. This significant improvement in PLQY indicates, on the one hand, that the introduction of ZnBr2 may have optimized the crystal structure of the thin film, reducing non-radiative recombination centers and thus promoting the radiative recombination process of excitons; on the other hand, it may also be related to the fact that ZnBr2 improves the band structure of the thin film, promoting the efficient recombination of electrons and holes. In summary, the thin film using ZnBr2 to replace 15% of PbBr2 not only achieved a new level of luminous efficiency but also exhibited superior energy conversion efficiency, providing strong experimental evidence and a theoretical foundation for developing high-performance light-emitting devices, improving energy utilization efficiency, and expanding the application fields of optoelectronic materials.

[0090] Figure 5 The current density-voltage-luminance curves for PeLEDs in Example 1 (15% substitution), Comparative Example 1 (0% substitution), Example 2 (10% substitution), Example 3 (20% substitution), and Example 4 (30% substitution) are shown. According to the test results, the prepared PeLEDs exhibited significant luminance variations under different ZnBr2 substitution ratios for PbBr2. Particularly noteworthy is that when the ZnBr2 substitution ratio for PbBr2 reached 15%, the prepared PeLED achieved the highest luminance, specifically 7172 cd / m². 2 This result far exceeds that of no replacement (0% replacement, brightness 5926 cd / m²). 2 ) and other substitution ratios (e.g., brightness is 6078 cd / m² when 10% is substituted) 2 When 20% is replaced, the brightness drops to 5479 cd / m². 2 When 30% is replaced, the brightness further decreases to 3497 cd / m². 2PeLEDs using ZnBr2 instead of 15% PbBr2 exhibit higher brightness, meaning they can convert more electrical energy into light energy with extremely high efficiency during electroluminescence. This improved conversion efficiency not only reflects the optimization of the electron-hole recombination mechanism within the PeLED but also indicates that adjustments to the material structure and bandgap arrangement help reduce non-radiative recombination losses, allowing more energy to be released in the form of photons.

[0091] Figure 6 The current density-external quantum efficiency (EQE) graphs for PeLEDs in Example 1 (15% substitution), Comparative Example 1 (0% substitution), Example 2 (10% substitution), Example 3 (20% substitution), and Example 4 (30% substitution) are shown. According to the test results, the prepared PeLEDs exhibited significant EQE changes under different ratios of ZnBr2 substitution for PbBr2. Specifically, when the ZnBr2 substitution ratio for PbBr2 was 15%, the prepared PeLED exhibited the highest EQE value, reaching 21.5%. This value far exceeds that of PeLEDs without substitution (i.e., 0% substitution, EQE 7.1%) and other substitution ratios (e.g., 10% substitution, EQE 12.7%; 20% substitution, EQE decreasing to 8.4%; and 30% substitution, further decreasing to 5.0%). This result fully demonstrates that the substitution of PbBr2 with ZnBr2 at an appropriate ratio can significantly improve the luminous efficiency of PeLEDs and optimize their photoelectric conversion performance. Replacing 15% of ZnBr2 may have effectively adjusted the band structure of PeLEDs, promoting electron and hole injection and recombination, and reducing nonradiative recombination losses, thus achieving a significant improvement in EQE. Furthermore, with further increases in the ZnBr2 substitution ratio (such as 20% and 30%), the EQE actually decreased. This may be because the excessive introduction of ZnBr2 disrupted the internal structure of the PeLED, increasing defect states and nonradiative recombination centers, thereby affecting luminous efficiency and photoelectric performance.

[0092] Figure 7The electroluminescence (EL) spectra of PeLED devices from Examples 1 (15% substitution), Comparative Example 1 (0% substitution), Example 2 (10% substitution), Example 3 (20% substitution), and Example 4 (30% substitution) are shown. According to the test results, as the substitution ratio of ZnBr2 to PbBr2 increased, the EL spectra of the prepared devices underwent subtle but clear changes. Specifically, the EL peak wavelength of the unsubstituted device (0% substitution) was 510 nm, while when the substitution ratio increased to 10%, the EL peak wavelength slightly decreased to 508 nm. Further increasing the substitution ratio to 15%, the EL peak wavelength continued to decrease slightly to 507 nm, showing a blue shift trend. However, when the substitution ratio reached 20% and 30%, the EL peak wavelength stabilized at 508 nm and no longer decreased. This spectral change indicates that the introduction of ZnBr2 has a significant impact on the luminescent properties of PeLEDs. The differences in crystal structure, band structure, and electronic transition energy levels between ZnBr2 and PbBr2 can lead to an increase in the band gap of the luminescent material as the substitution ratio increases, resulting in a blue shift in the emission spectrum towards shorter wavelengths. However, when the substitution ratio exceeds a certain limit (e.g., 15%), the blue shift trend may saturate. This is likely because the stability of the internal structure of the material begins to dominate, limiting further bandgap adjustments. Furthermore, the fact that the EL peak wavelength no longer changes after the substitution ratio exceeds 15% also indicates that although the introduction of ZnBr2 alters the luminescence characteristics of PeLEDs to some extent, excessively high substitution ratios may not always be beneficial for obtaining superior performance.

[0093] Figure 8 The chart shows the operating lifetime of the PeLED devices in Example 1 (replacement of 15%) and Comparative Example 1 (replacement of 0%). Based on the test results, at an initial luminance of 100 cd / m²... 2 Under these conditions, PeLED devices fabricated by replacing 15% of PbBr2 with ZnBr2 exhibited significantly enhanced operational stability, with their T... 50 The lifetime reached 3.72 hours, compared to the lifetime T of the unreplaced PeLED device. 50The lifetime was only 0.86 hours. This significant increase in lifetime demonstrates that appropriate substitution of ZnBr2 has a positive effect on improving the durability of PeLED devices. The longer device lifetime can be attributed to several factors: First, the introduction of ZnBr2 may optimize the crystal structure and bandgap arrangement of the material, reducing non-radiative recombination processes, thereby improving luminous efficiency and device stability. Second, the interaction between ZnBr2 and PbBr2 may improve the thermal and chemical stability of the material, allowing the device to maintain good performance under high temperature or long-term operating conditions. Furthermore, the substitution of ZnBr2 may also affect the charge transport and balance within the device, promoting more efficient carrier injection and recombination processes, further extending the device lifetime.

[0094] Figure 9 Two-dimensional contour pseudocolor maps of the spectral stability of PeLED devices from Examples 1 (15% substitution), Comparative Example 1 (0% substitution), Example 2 (10% substitution), and Example 3 (20% substitution) at different voltages are shown. According to the test results, these PeLED devices all exhibited excellent spectral stability with increasing ZnBr2 substitution for PbBr2. Regardless of whether the operating conditions were low or high voltage, the spectra of each device did not show significant shifts, which fully demonstrates that appropriate substitution of ZnBr2 did not adversely affect the spectral characteristics of the PeLED devices. On the contrary, the introduction of ZnBr2 may indirectly promote the improvement of spectral stability by improving the band structure of the material, reducing defect states, or optimizing charge transport paths.

[0095] Figure 10 The figures show the current density-external quantum efficiency (EQE) graphs for PeLEDs in Example 1 (with BPCA additive) and Comparative Example 2 (with PABP additive). According to the test results, when 15% of PbBr2 is replaced with ZnBr2, the PeLED device using BPCA additive exhibits a remarkable external quantum efficiency (EQE) of 21.5%, almost four times that of the device using PABP additive (EQE of 5.6%). This significant difference directly demonstrates the superior performance of BPCA additive in promoting exciton formation, reducing nonradiative recombination, and improving light extraction efficiency.

[0096] The above description provides a detailed account of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

Claims

1. A composition of zinc-lead halide quasi-two-dimensional green perovskite, characterized in that, The raw materials for preparing the zinc-lead halide quasi-two-dimensional green perovskite composition include: tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate and zinc bromide; the raw materials for preparing the zinc-lead halide quasi-two-dimensional green perovskite composition also include: cesium bromide, lead bromide, zinc bromide and phenylbutylamine bromide. Based on a molar ratio, the cesium bromide, lead bromide, zinc bromide, phenylbutylamine bromide, and tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate are in the following proportions: 1–1.2: 1–x: x: 0.4–0.8: 0.1–0.5; 0＜x≤30％。 2. A method for preparing the zinc-lead halide quasi-two-dimensional green perovskite composition as described in claim 1, characterized in that, The process includes the following steps: In solution, cesium bromide, lead bromide, zinc bromide, phenylbutylamine bromide and tert-butyl bis(4-methoxyphenyl)phosphoxy]carbamate are mixed and heated to react, thus obtaining the product.

3. The preparation method according to claim 2, characterized in that, In the solution state, Pb 2+ With Zn 2+ The sum of their concentrations is 0.04–0.06 mol / L.

4. A perovskite thin film, characterized in that, The perovskite film is prepared from the composition of the zinc-lead halide quasi-two-dimensional green perovskite according to claim 1.

5. A perovskite light-emitting diode, characterized in that, It includes an anode conductive glass layer, a hole transport layer, an interface modification layer, a perovskite light-emitting layer, an electron transport layer, an electron injection layer, and a cathode layer, which are stacked sequentially. The perovskite light-emitting layer is the perovskite thin film as described in claim 4.

6. The perovskite light-emitting diode according to claim 5, characterized in that, The electron transport layer is made of at least one of the following: 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene, 2,4,6-tris[3-(diphenylphosphoxy)phenyl]-1,3,5-triazole, 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline, and 4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine.

7. The perovskite light-emitting diode according to claim 5, characterized in that, The hole transport layer is made of poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine).

8. The perovskite light-emitting diode according to claim 5, characterized in that, The material of the interface modification layer includes at least one of lithium fluoride and oxyacid lithium salt.

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