Multifunctional isocyanate crosslinking modified perovskite solar cell and preparation method thereof

Abstract

The application provides a multifunctional isocyanate crosslinking modified perovskite solar cell and a preparation method thereof. The application adopts thiophosphoric acid triphenyl isocyanate (TPTI), the isocyanate of which can be subjected to nucleophilic addition with organic cations in PEAI, the triphenyl structure is subjected to strong pi-pi stacking with PEAI, and the isocyanate group is subjected to self-crosslinking under mild conditions to construct a chemical network, in-situ anchor easy migration ions, and realize interface defect passivation. Meanwhile, the P=S bond of TPTI is subjected to charge transfer with PCBM to form steric hindrance to inhibit PCBM self-aggregation, and is subjected to interaction with perovskite components to rebuild a surface termination layer, realizing synergistic passivation and stability. Through chemical bonding and crosslinking network, the application significantly strengthens the stability of the interface and the electron transport layer, effectively improves the photoelectric conversion efficiency and long-term stability of the perovskite solar cell, and solves technical pain points such as unstable cell interface and fast carrier recombination.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and in particular to a multifunctional isocyanate crosslinked modified perovskite solar cell and its preparation method. Background Technology

[0002] Currently, inverted single-junction perovskite solar cells (PINs) have become a research hotspot in the photovoltaic field due to their low fabrication cost, compatibility with flexible substrates, tandem solar cell capability, and excellent photothermal stability. Their certified power conversion efficiency (PCE) has exceeded 27%, gradually approaching the theoretical efficiency limit of single-junction perovskite cells. However, despite significant efficiency breakthroughs, the long-term stability of these devices remains limited by the upper interface (perovskite / electron transport layer). This interface, as a key hub for electron transport, requires the integration of multiple functional layers to achieve passivation, charge transport, interface modification, and other functions. It is prone to nonradiative recombination and a decrease in charge extraction efficiency, becoming a constraint on the device's VV. OC (Open circuit voltage) boost and J SC The core bottleneck is the loss of (short-circuit current density).

[0003] Firstly, there's the passivation of the upper interface. Currently, ammonium salt passivation is an effective strategy for improving the performance and stability of perovskite solar cells. Among them, phenylethyl ammonium iodide (PEAI) is considered to significantly improve the open-circuit voltage and fill factor (FF). However, PEA itself... + The cations exhibit high mobility under high temperatures or light exposure, allowing them to penetrate the perovskite phase and easily leading to defects such as short-circuit current density (JSC) loss and poor thermal stability. Secondly, PCBM ([6,6]-phenyl-C 61 PEAI (methyl butyrate) has become an indispensable electron transport material in inverted PSCs (perovskite solar cells) due to its excellent electron transport properties, good solubility and processability, and energy level matching advantages. However, under long-term high temperature and light exposure, PCBM molecules are prone to dimerization, increasing charge recombination loss and charge accumulation at the interface, and reducing the long-term stability of the device. To address these issues, researchers have tried various strategies, such as inserting polymer physical barrier layers or molecular modification to suppress ion migration, or doping with small molecules to regulate the stacking behavior of PCBM to suppress its self-aggregation. However, these strategies often rely on physical doping or simple molecular modification, making it difficult to maintain the structural stability of the interface and electron transport layer under long-term operating conditions. In addition, most current studies only optimize for single problems and lack synergistic strategies that can simultaneously suppress PEAI ion migration and PCBM dimerization. Summary of the Invention

[0004] To address the aforementioned technical deficiencies, this invention provides a multifunctional isocyanate crosslinked modified perovskite solar cell and its preparation method. This invention utilizes a multifunctional isocyanate crosslinking agent—triphenyl thiophosphate (TPTI)—which can simultaneously "lock" interfacial ions and "stabilize" ETL materials. The isocyanate ion (-NCO) in TPTI exhibits high electrophilic reactivity, enabling it to react with excess organic cations in PEAI (such as PEA). + TPTI undergoes nucleophilic addition reactions, and the triphenyl structure within the TPTI molecule itself can form a strong π-π stacking interaction with PEAI. Its isocyanate groups can also undergo self-crosslinking under mild conditions, forming a robust chemical network that chemically "anchors" these easily migrating ions in situ. Furthermore, the P=S bonds in TPTI are rich in lone pair electrons, enabling charge transfer with PCBM. This chemical interaction disrupts the topological chemical arrangement conditions of [2+2] cycloaddition, creating steric hindrance and effectively suppressing self-aggregation between PCBM molecules. It also interacts with the organic and inorganic components of perovskite and reconstructs the perovskite surface termination layer, achieving synergistic passivation. Compared to traditional physical doping strategies, TPTI provides more stable and durable protection for the interface and ETL layer through chemical bonding and crosslinking networks. Based on this strategy, this invention successfully fabricated a perovskite solar cell with both high efficiency and high stability, providing a new chemical control approach for achieving long-lifetime operation of solar cells under thermal stress.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a multifunctional isocyanate crosslinked modified perovskite solar cell, comprising a conductive substrate layer, a hole transport layer, a hole side interface modification layer, a perovskite light absorption layer, a passivation layer, a multifunctional crosslinked modified layer, an electron transport layer, a hole blocking layer, a protective layer, and a metal electrode layer stacked sequentially.

[0007] The material of the multifunctional crosslinked modified layer is triphenyl isocyanate thiophosphate;

[0008] The passivation layer contains PEAI in its material;

[0009] The electron transport layer is made of PCBM.

[0010] Preferably, the conductive substrate layer is selected from any one of ITO, FTO, and AZO;

[0011] The hole transport layer is made of at least one of 4PADCB, CuI, CuSCN, PEDOT:PSS, and PTAA.

[0012] The material of the hole-side interface modification layer is at least one of Al2O3, SiO2, ZrO2, HfO2, and MgO;

[0013] The perovskite light-absorbing layer material is APbX3, wherein A is at least one of methylamine, formamidinium, and cesium, and X is at least one of chlorine, bromine, and iodine;

[0014] The passivation layer is made of PEAI and EDAI2; the hole blocking layer is made of C. 60 C 70 ICBA, PC 61 BM, PC 71 At least one of BM, ZnO, and SnO2;

[0015] The material of the protective layer is at least one of SnO2, ZnO, Al2O3, and HfO2;

[0016] The material of the metal electrode layer is at least one of Ag, Au, Cu, and Al.

[0017] Secondly, the present invention also provides a method for preparing the perovskite solar cell, comprising the following steps:

[0018] A hole transport layer, a hole side interface modification layer, and a perovskite light absorption layer are sequentially prepared on a conductive substrate layer.

[0019] A solution containing PEAI was prepared to obtain a PEAI solution; the PEAI solution was coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer;

[0020] Prepare a solution containing triphenyl isocyanate thiophosphate to obtain a triphenyl isocyanate thiophosphate solution; coat the triphenyl isocyanate thiophosphate solution onto the surface of the passivation layer, or immerse the passivation layer in the triphenyl isocyanate thiophosphate solution to form a multifunctional crosslinked modified layer on the surface of the passivation layer.

[0021] A solution containing PCBM was prepared to obtain a PCBM solution; the PCBM solution was coated on the surface of a multifunctional crosslinked modified layer and annealed to obtain an electron transport layer;

[0022] A hole blocking layer, a protective layer, and a metal electrode layer are sequentially fabricated on the electron transport layer to obtain a perovskite solar cell.

[0023] Preferably, triphenyl isocyanate thiophosphate is added to ethyl acetate to prepare a triphenyl isocyanate thiophosphate solution with a concentration of 0.01~2 mg / mL;

[0024] A triphenyl isocyanate solution of thiophosphate was spin-coated onto the surface of the passivation layer, wherein the spin-coating speed was 4000~4500 r / min and the spin-coating time was 30~60 s;

[0025] The passivation layer is immersed in a solution of triphenyl isocyanate thiophosphate for 1 to 60 seconds.

[0026] Preferably, PEAI and EDAI2 are added to isopropanol to obtain a PEAI solution; the concentration of PEAI in the PEAI solution is 1~2 mg / mL and the concentration of EDAI2 is 0.5~1 mg / mL;

[0027] PEAI solution was spin-coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer. The spin-coating speed was 4000~4500 r / min, the spin-coating time was 30~60 s, and the annealing temperature was 100~110℃ for 5~10 min.

[0028] Preferably, PCBM is added to chlorobenzene to obtain a PCBM solution; the concentration of PCBM in the PCBM solution is 10~15 mg / mL;

[0029] The PCBM solution was spin-coated onto the surface of the multifunctional crosslinked modified layer and then annealed to obtain the electron transport layer. The spin-coating speed was 7000~8000 r / min, the spin-coating time was 30~60s, and the annealing temperature was 75~85℃ for 5~10min.

[0030] Preferably, the perovskite light-absorbing layer material is FA. 0.95 Cs 0.05 PbI3;

[0031] The perovskite light-absorbing layer is prepared by adding CsI, FAI, PbI2, and MACl to a solvent to obtain a perovskite precursor solution.

[0032] The perovskite precursor solution was spin-coated onto the surface of the hole-side interface modification layer and annealed to obtain the perovskite light-absorbing layer. The spin-coating speed was 2000~4000 r / min, the spin-coating time was 10~60s, and chlorobenzene was added during spin-coating. The annealing temperature was 100~110℃ and the time was 30~35 min.

[0033] Preferably, the hole transport layer material is 4PADCB, and the method for preparing the hole transport layer is as follows:

[0034] 4PADCB was added to ethanol to obtain a 4PADCB solution with a concentration of 0.5~1 mg / mL;

[0035] A 4PADCB solution was spin-coated onto the surface of a conductive substrate and then annealed to obtain a hole transport layer. The spin-coating speed was 3000~4000 r / min and the spin-coating time was 30~60s. The annealing temperature was 100~110℃ and the annealing time was 10~15 min.

[0036] Preferably, the material of the hole-side interface modification layer is Al2O3;

[0037] Al2O3 was added to isopropanol to obtain an Al2O3 solution with a concentration of 0.02~1 mg / mL;

[0038] Al2O3 solution was spin-coated onto the surface of the hole transport layer and annealed to obtain a hole-side interface modification layer. The spin-coating speed was 5000~5500 r / min and the spin-coating time was 30~60s. The annealing temperature was 100~110℃ and the annealing time was 5~10 min.

[0039] Preferably, a hole blocking layer is prepared on the surface of the electron transport layer by thermal evaporation, wherein the evaporation rate is 0.05~0.1 Å / s;

[0040] A protective layer was deposited on the surface of the hole-blocking layer using atomic layer deposition (ALD).

[0041] A metal electrode layer was prepared on the surface of the protective layer by thermal evaporation, wherein the evaporation rate was 0.1~1 Å / s.

[0042] The multifunctional isocyanate crosslinked modified perovskite solar cell and its preparation method of the present invention have the following advantages compared with the prior art:

[0043] The multifunctional isocyanate crosslinked modified perovskite solar cell of the present invention uses a multifunctional isocyanate crosslinking agent—triphenyl thiophosphate (TPTI), which can simultaneously "lock" interfacial ions and "stabilize" ETL materials. The isocyanate (-NCO) in triphenyl thiophosphate (TPTI) has high electrophilic reactivity and can react with excess organic cations in PEAI (such as PEA). +TPTI undergoes nucleophilic addition reactions, and the triphenyl structure contained in the TPTI molecule itself can form a strong π-π stacking interaction with PEAI. Its isocyanate groups can also undergo self-crosslinking under mild conditions to form a robust chemical network, which in situ chemically "anchors" these easily migrating ions. In addition, the P=S bonds in TPTI are rich in lone pair electrons, which can achieve charge transfer with PCBM. This chemical interaction can disrupt the topological chemical arrangement conditions of [2+2] cycloaddition, form steric hindrance, effectively inhibit the self-aggregation between PCBM molecules, and interact with the organic and inorganic components of perovskite to rebuild the perovskite surface termination layer, achieving synergistic passivation. Compared with traditional physical doping strategies, TPTI provides more stable and durable protection for the interface and ETL layer through chemical bonding and crosslinking networks. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the perovskite solar cell structure of the present invention;

[0046] Figure 2 TPTI, PEAI, and a mixture of both TPTI and PEAI. 1 H nuclear magnetic resonance spectrum;

[0047] Figure 3 TPTI, formamidine hydroiodide (FAI), and a mixture of TPTI and FAI. 1 H nuclear magnetic resonance spectrum;

[0048] Figure 4 Infrared spectra of TPTI, PEAI, and their mixtures;

[0049] Figure 5 High-resolution mass spectra of undoped PCBM and TPTI-doped PCBM;

[0050] Figure 6 The current density-voltage (JV) graphs are shown for the perovskite solar cells prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the 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 protection of the present invention.

[0052] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0053] This application provides a multifunctional isocyanate crosslinked modified perovskite solar cell, such as... Figure 1 As shown, it includes a conductive substrate layer 1, a hole transport layer 2, a hole side interface modification layer 3, a perovskite light absorption layer 4, a passivation layer 5, a multifunctional crosslinking modification layer 6, an electron transport layer 7, a hole blocking layer 8, a protective layer 9, and a metal electrode layer 10, which are stacked in sequence.

[0054] Among them, the material of the multifunctional crosslinked modified layer 6 is triphenyl isocyanate thiophosphate;

[0055] The material of passivation layer 5 contains PEAI;

[0056] The material of electron transport layer 7 is PCBM.

[0057] The triphenyl isocyanate thiophosphate (TPTI) of this invention has the chemical formula: C 21 H 12 N3O6PS, chemical structural formula is: The triphenyl isocyanate thiophosphate used in this invention can simultaneously "lock" interfacial ions and "stabilize" ETL (electron transport layer) materials. The isocyanate (-NCO) group in triphenyl isocyanate thiophosphate (TPTI) has high electrophilic reactivity and can react with PEAI (phenylethyl ammonium iodide, chemical formula C8H). 12 Excess organic cations (such as PEA) in IN)+ TPTI undergoes nucleophilic addition reactions, and the triphenyl structure contained in the TPTI molecule itself can form a strong π-π stacking interaction with PEAI. Its isocyanate groups can also undergo self-crosslinking under mild conditions to form a robust chemical network, chemically "anchoring" these easily migrating ions in situ. In addition, the P=S bond in TPTI is rich in lone pair electrons, which can react with PCBM ([6,6]-phenyl-C 61 Charge transfer is achieved between methyl butyrate (-butyrate), and this chemical action can disrupt the topological chemical arrangement conditions of [2+2] cycloaddition (i.e., the chemical reaction in which two double bonds each give up 2 π electrons to form a four-membered ring), forming steric hindrance, effectively inhibiting the self-aggregation between PCBM molecules, interacting with the organic and inorganic components of perovskite and rebuilding the perovskite surface termination layer to achieve synergistic passivation; compared with the traditional physical doping strategy, TPTI provides more stable and durable protection for the interface and ETL layer through chemical bonding and cross-linking network.

[0058] In some embodiments, the conductive substrate 1 is selected from any one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO);

[0059] The material of hole transport layer 2 is at least one of 4PADCB ([4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid), CuI, CuSCN, PEDOT:PSS, and PTAA;

[0060] The material of the hole-side interface modification layer 3 is at least one of Al2O3, SiO2, ZrO2, HfO2, and MgO;

[0061] The perovskite light-absorbing layer 4 is made of APbX3, wherein A is at least one of methylamine, formamidinium, and cesium, and X is at least one of chlorine, bromine, and iodine;

[0062] The materials of passivation layer 5 include PEAI and EDAI2 (ethylenediamine dihydroiodide, C2H9IN2); the material of hole blocking layer is C 60 C 70 ICBA, PC 61 BM, PC 71 At least one of BM, ZnO, and SnO2;

[0063] The material of the protective layer 9 is at least one of SnO2, ZnO, Al2O3, and HfO2;

[0064] The metal electrode layer 10 is arranged in an array on the surface of the protective layer 9, and the material of the metal electrode layer 10 is at least one of Ag, Au, Cu and Al.

[0065] In some embodiments, the thickness of the conductive substrate layer 1 is 80-200 nm, the thickness of the hole transport layer 2 is 2-20 nm, the thickness of the hole side interface modification layer 3 is 2-20 nm, the thickness of the perovskite light absorption layer 4 is 500-1000 nm, the thickness of the passivation layer 5 is 2-20 nm, the thickness of the multifunctional crosslinking modified layer 6 is 2-20 nm, the thickness of the electron transport layer 7 is 15-50 nm, the thickness of the hole blocking layer 8 is 10-20 nm, the thickness of the protective layer 9 is 10-30 nm, and the thickness of the metal electrode layer 10 is 100-200 nm.

[0066] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned perovskite solar cell, comprising the following steps:

[0067] S1. A hole transport layer, a hole side interface modification layer, and a perovskite light absorption layer are sequentially prepared on a conductive substrate layer.

[0068] S2. Prepare a solution containing PEAI to obtain a PEAI solution; coat the PEAI solution onto the surface of the perovskite light-absorbing layer, anneal, and obtain a passivation layer;

[0069] S3. Prepare a solution containing triphenyl isocyanate thiophosphate to obtain a triphenyl isocyanate thiophosphate solution; coat the triphenyl isocyanate thiophosphate solution onto the surface of the passivation layer, or immerse the passivation layer in the triphenyl isocyanate thiophosphate solution to form a multifunctional crosslinked modified layer on the surface of the passivation layer.

[0070] S4. Prepare a solution containing PCBM to obtain a PCBM solution; coat the PCBM solution onto the surface of the multifunctional crosslinked modified layer, and anneal to obtain an electron transport layer;

[0071] S5. A hole blocking layer, a protective layer, and a metal electrode layer are sequentially fabricated on the electron transport layer to obtain a perovskite solar cell.

[0072] In some embodiments, triphenyl isocyanate thiophosphate is added to ethyl acetate to prepare a triphenyl isocyanate thiophosphate solution with a concentration of 0.01~2 mg / mL;

[0073] A triphenyl isocyanate solution of thiophosphate was spin-coated onto the surface of the passivation layer. The spin-coating speed was 4000~4500 r / min, the spin-coating time was 30~60 s, and the acceleration was 2000~3000 rpm / min.

[0074] The passivation layer is immersed in a solution of triphenyl isocyanate thiophosphate for 1 to 60 seconds.

[0075] In the above embodiments, the multifunctional crosslinked modified layer can be prepared by immersion or spin coating; wherein, immersion is preferred, as it ensures that TPTI molecules can be uniformly and isotropically modified on a large-area bulk film, overcoming the inherent limitation of the traditional spin coating method: the coffee ring effect.

[0076] In some embodiments, PEAI and EDAI2 are added to isopropanol to obtain a PEAI solution; the concentration of PEAI in the PEAI solution is 1~2 mg / mL and the concentration of EDAI2 is 0.5~1 mg / mL.

[0077] PEAI solution was spin-coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer. The spin-coating speed was 4000~4500 r / min, the spin-coating time was 30~60 s, the acceleration was 2000~3000 rpm / min, the annealing temperature was 100~110℃, and the annealing time was 5~10 min.

[0078] In some embodiments, PCBM is added to chlorobenzene to obtain a PCBM solution; the concentration of PCBM in the PCBM solution is 10~15 mg / mL.

[0079] The PCBM solution was spin-coated onto the surface of the multifunctional crosslinked modified layer and annealed to obtain the electron transport layer. The spin-coating speed was 7000~8000 r / min, the spin-coating time was 30~60s, the acceleration was 3000~4000 rpm / min, the annealing temperature was 75~85℃, and the annealing time was 5~10min.

[0080] In some embodiments, the perovskite light-absorbing layer material is FA. 0.95 Cs 0.05 PbI3;

[0081] The perovskite light-absorbing layer is prepared as follows: CsI, FAI (formamidinium hydroiodide, HC(NH2)2I), PbI2, and MACl (methylamine hydrochloride, CH3NH3Cl) are added to a solvent to obtain a perovskite precursor solution; wherein the solvent includes DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide), and the volume ratio of DMF to DMSO is (4~6):1; the concentration of the perovskite precursor solution is 1~2 mol / L based on PbI2; the perovskite precursor solution is spin-coated onto the surface of the hole-side interface modification layer and annealed to obtain the perovskite light-absorbing layer; wherein the spin-coating speed is 2000~4000 r / min, the spin-coating time is 10~60s, the acceleration is 2000~3000 rpm / min, and chlorobenzene is added during spin-coating (as an anti-solvent to induce rapid crystallization of perovskite); the annealing temperature is 100~110℃ and the time is 30~35min.

[0082] In some embodiments, the hole transport layer material is 4PADCB, and the method for preparing the hole transport layer is as follows:

[0083] 4PADCB was added to ethanol to obtain a 4PADCB solution with a concentration of 0.5~1 mg / mL;

[0084] A 4PADCB solution was spin-coated onto the surface of a conductive substrate and then annealed to obtain a hole transport layer. The spin-coating speed was 3000~4000 r / min, the spin-coating time was 30~60s, and the acceleration was 1000~2000 rpm / min. The annealing temperature was 100~110℃ and the annealing time was 10~15 min.

[0085] In some embodiments, the material of the hole-side interface modification layer is Al2O3;

[0086] Al2O3 was added to isopropanol to obtain an Al2O3 solution with a concentration of 0.02~1 mg / mL;

[0087] Al2O3 solution was spin-coated onto the surface of the hole transport layer and annealed to obtain a hole-side interface modification layer. The spin-coating speed was 5000~5500 r / min, the spin-coating time was 30~60s, and the acceleration was 2000~3000 rpm / min. The annealing temperature was 100~110℃ and the annealing time was 5~10 min.

[0088] In some embodiments, a hole-blocking layer is prepared on the surface of the electron transport layer by thermal evaporation, wherein the evaporation rate is 0.05~0.1 Å / s; 1 Å = 10 -10 rice.

[0089] A protective layer was deposited on the surface of the hole-blocking layer using atomic layer deposition (ALD).

[0090] A metal electrode layer was prepared on the surface of the protective layer by thermal evaporation, wherein the evaporation rate was 0.1~1 Å / s.

[0091] Specifically, if the protective layer material is SnO2, its specific preparation method is as follows: using tetratetra(dimethylamino)tin (TDMASn) as the tin source and deionized water (H2O) as the oxygen source, the protective layer is prepared by alternating pulse-purge cycles of tin source / water source on the surface of the hole blocking layer through atomic layer deposition; wherein, the deposition cycle number is controlled at 50~300 cycles, the deposition temperature at 80~150℃, and the pulse / purge time at 0.01~1 s and 5~10 s, respectively.

[0092] In some embodiments, before the hole transport layer is prepared on the surface of the conductive substrate, the conductive substrate is further cleaned, specifically by placing the conductive substrate in water and ethanol in sequence for ultrasonic treatment.

[0093] The following detailed embodiments further illustrate the multifunctional isocyanate crosslinked modified perovskite solar cell and its preparation method. This section, in conjunction with specific embodiments, further explains the content of the invention, but should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in the art.

[0094] Example 1

[0095] This embodiment provides a method for preparing a multifunctional isocyanate crosslinked modified perovskite solar cell, including the following steps:

[0096] S1. Using ITO-coated glass (with an average ITO thickness of 100 nm) as the conductive substrate, the ITO glass is ultrasonically treated three times in deionized water for 10 min each time, and then ultrasonically treated in ethanol for 10 min. After being dried with nitrogen, it is ready for use.

[0097] S2. Add 4PADCB to ethanol to obtain a 4PADCB solution with a concentration of 0.5 mg / mL.

[0098] A 4PADCB solution was spin-coated onto an ITO surface and annealed to obtain a hole transport layer (average thickness of 10 nm). The spin-coating speed was 3000 r / min, the spin-coating time was 30 s, and the acceleration was 1000 rpm / min. The annealing temperature was 100℃ and the annealing time was 10 min.

[0099] S3. Add Al2O3 to isopropanol to obtain an Al2O3 solution with a concentration of 0.02 mg / mL;

[0100] Al2O3 solution was spin-coated onto the surface of the hole transport layer and annealed to obtain a hole-side interface modification layer (average thickness of 10 nm). The spin-coating speed was 5000 r / min, the spin-coating time was 30 s, and the acceleration was 2000 rpm / min. The annealing temperature was 100℃ and the annealing time was 5 min.

[0101] S4. 19.5 mg CsI, 245.06 mg FAI, 712.2 mg PbI2, and 10.12 mg MACl were added to a solvent to obtain a perovskite precursor solution; wherein the solvent included DMF and DMSO in a volume ratio of 4:1; the concentration of the perovskite precursor solution was 1.5 mol / L based on PbI2.

[0102] The perovskite precursor solution was spin-coated onto the surface of the hole-side interface modification layer, and then annealed to obtain the perovskite light-absorbing layer FA. 0.95 Cs 0.05 PbI3 (average thickness 800 nm); the process involved two-stage spin coating. In the first stage, the spin coating speed was 2000 r / min, the spin coating time was 10 s, and the acceleration was 2000 rpm / min. In the second stage, the spin coating speed was 4000 r / min, the spin coating time was 40 s, and the acceleration was 2000 rpm / min. 150 μL of chlorobenzene was added dropwise at the last 8 s, i.e., at 42 s.

[0103] The annealing temperature was 100℃ and the time was 30 min;

[0104] S5. Add PEAI and EDAI2 to isopropanol to obtain a PEAI solution; the concentration of PEAI in the PEAI solution is 1 mg / mL and the concentration of EDAI2 is 0.5 mg / mL.

[0105] PEAI solution was spin-coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer (average thickness of 10 nm); wherein the spin-coating speed was 4000 r / min, the spin-coating time was 30 s, the acceleration was 2000 rpm / min, the annealing temperature was 100℃, and the annealing time was 5 min.

[0106] S6. Add triphenyl thiophosphate (TPTI) to ethyl acetate to prepare a triphenyl thiophosphate solution with a concentration of 1 mg / mL.

[0107] The ITO with the passivation layer was immersed in a triphenyl isocyanate thiophosphate solution for 50 seconds to form a multifunctional cross-linked modified layer (average thickness of 10 nm) on the surface of the passivation layer.

[0108] S7. Add PCBM to chlorobenzene to obtain a PCBM solution; the concentration of PCBM in the PCBM solution is 10 mg / mL;

[0109] The PCBM solution was spin-coated onto the surface of the multifunctional crosslinked modified layer and annealed to obtain an electron transport layer (average thickness of 30 nm). The spin-coating speed was 7000 r / min, the spin-coating time was 30 s, the acceleration was 3000 rpm / min, and the annealing temperature was 75℃ for 5 min.

[0110] S8. A hole blocking layer C is prepared on the surface of the electron transport layer by thermal evaporation. 60 The process involves first depositing at 0.05 Å / s to 5 nm, and then depositing at 0.1 Å / s to 20 nm.

[0111] S9. A protective SnO2 layer was deposited on the surface of the hole-blocking layer using atomic layer deposition (ALD). The specific preparation method is as follows: using tetratetra(dimethylamino)tin (TDMASn) as the tin source and deionized water (H2O) as the oxygen source, alternating pulse-purge cycles of tin source / water source were performed on the surface of the hole-blocking layer using ALD to prepare a SnO2 protective layer with an average thickness of 20 nm. The deposition cycle number was controlled at 200 cycles, the deposition temperature at 120℃, and the pulse / purge times were 0.3 s and 8 s, respectively.

[0112] S10. A metal electrode layer Ag is prepared on the surface of the protective layer by thermal evaporation, wherein the electrode layer is first deposited at 0.1 Å / s to 10 nm, then at 0.2 Å / s to 30 nm, then at 0.4 Å / s to 50 nm, and then at 1 Å / s to 100 nm.

[0113] Comparative Example 1

[0114] This comparative example provides a method for preparing a perovskite solar cell, which is the same as in Example 1, except that it does not contain a multifunctional crosslinking modification layer, and the electron transport layer is prepared directly on the surface of the passivation layer. All other aspects are the same as in Example 1.

[0115] Performance testing

[0116] Figure 2 It consists of TPTI, PEAI, and a mixture of both (in a 1:1 mass ratio). 1 H nuclear magnetic resonance spectrum;

[0117] Figure 3 It consists of TPTI, formamidine hydroiodide (FAI), and a mixture of TPTI and FAI (mass ratio 1:1). 1 H nuclear magnetic resonance spectrum;

[0118] use 1 H NMR was used to investigate the chemical reactions of TPTI with PEAI and the perovskite organic component FAI, such as Figures 2-3 As shown, the amino group of PEAI undergoes a nucleophilic addition reaction with the isocyanate group (-NCO) of TPTI to form a urea bond (-NH-CO-NH-, 8.62 ppm). Figure 2 PEAI's -NH3 + ( Figure 2The concentration of urea (7.74 ppm) disappeared, and a new characteristic peak of urea bonds appeared. Figure 2 (b, 8.62 ppm); FAI interacts with the carbonyl group of TPTI through hydrogen bonding. This interaction is FA + amino group in Figure 3 The presence of c (8.83 ppm) provided a unique chemical environment, resulting in 9.03 ppm ( Figure 3 The singlet of (e) and 8.67 ppm ( Figure 3 The two states in f). Meanwhile, in FA... + CH- ( Figure 3 The initial state of (d, 7.85 ppm) was a singlet state, which split into a multiply state ( Figure 3 (g). TPTI and FAI can undergo a nucleophilic addition reaction, and the reaction product further reacts with isocyanate groups to form a three-dimensional network structure and gel, resulting in the complete quenching of its NMR signal.

[0119] Figure 4 The infrared spectra of TPTI, PEAI and their mixture (mass ratio 1:1) are shown.

[0120] To demonstrate the crosslinking of TPTI, Fourier transform infrared spectroscopy (FTIR) tests were performed in this invention, such as... Figure 4 As shown, TPTI's -NCO (2274 cm⁻¹) -1 The disappearance of the characteristic peak indicates that -NCO was completely reacted, and TPTI reacted with PEAI to form a urea bond (1700 cm⁻¹). -1 Furthermore, TPTI itself is cross-linked (dimer or trimer), resulting in very high ring strain, which strongly restricts the vibration of the carbonyl group, significantly increasing the vibration frequency (the carbonyl peak shifts to the right). The absorption of the urea bond (-NH-CO-NH-) carbonyl group and the isocyanurate carbonyl group overlaps, resulting in a significantly broadened and asymmetrical absorption peak.

[0121] Figure 5 High-resolution mass spectra of undoped PCBM and TPTI-doped PCBM.

[0122] To evaluate the effect of TPTI in inhibiting PCBM dimer, a PCBM solution (obtained by adding PCBM to the solvent chlorobenzene CB) and a PCBM / TPTI mixed solution (obtained by adding PCBM and TPTI to the solvent chlorobenzene CB in a 1:1 mass ratio) were heated at 85°C for 120 h, and high-resolution mass spectrometry was performed. Figure 5 As shown. Figure 5In the equation, m / z = 911.1 is the characteristic mass-to-charge ratio of the PCBM monomer, and m / z = 1839.2 is the characteristic mass-to-charge ratio of the PCBM dimer. Figure 5 In the study, pure PCBM underwent a dimerization reaction after being aged in chlorobenzene solvent at 85°C for 120 hours, forming a dimer product with m / z = 1839.2. This dimer product was detected by mass spectrometry, demonstrating that high temperature is the key factor inducing PCBM dimerization. However, when TPTI coexisted with PCBM, no dimer signal was observed after high-temperature aging. The core reason is that the P=S bonds in TPTI are rich in lone pair electrons, enabling charge transfer with PCBM and blocking the active sites for dimerization in PCBM molecules. This inhibits the formation of PCBM dimers, fundamentally eliminating the dimer's mass spectrometric signal.

[0123] Figure 6 The current density-voltage (JV) plots of perovskite solar cells prepared for the control group (i.e., Comparative Example 1) and the TPTI-treated experimental group (i.e., Example 1) are shown.

[0124] Perovskite solar cells were prepared according to the methods in Example 1 and Comparative Example 1, and their open-circuit voltages (V) were tested. OC ), short-circuit current density (J SC The results of fill factor (FF%) and photoelectric conversion efficiency (PCE%) are shown in Table 1 below:

[0125] Table 1 - Performance of different perovskite solar cells

[0126]

[0127] from Figure 6 As shown in Table 1, the open-circuit voltage of the perovskite solar cell in Comparative Example 1 is 1.17 V, and the short-circuit current density is 22.54 mA / cm². 2 The fill factor was 81.72%, and the photoelectric conversion efficiency was only 21.64%; while in Example 1, the open-circuit voltage of the perovskite solar cell was increased to 1.19 V, and the short-circuit current density was increased to 22.87 mA / cm². 2 The fill factor was significantly improved to 85.64%, and the photoelectric conversion efficiency reached 23.49%, which was 1.85% higher than that of Comparative Example 1.

[0128] The above results show that, after adopting the multifunctional isocyanate crosslinking layer of the present invention, all photoelectric performance parameters of the perovskite solar cell are significantly improved, especially the fill factor, which indicates that interface defects are effectively passivated, carrier recombination is suppressed, charge extraction and transport are more efficient, and ultimately a significant improvement in photoelectric conversion efficiency is achieved.

[0129] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A multifunctional isocyanate crosslinked modified perovskite solar cell, characterized in that, It includes a conductive substrate layer, a hole transport layer, a hole side interface modification layer, a perovskite light absorption layer, a passivation layer, a multifunctional cross-linking modification layer, an electron transport layer, a hole blocking layer, a protective layer, and a metal electrode layer, which are stacked in sequence. The material of the multifunctional crosslinked modified layer is triphenyl isocyanate thiophosphate; The passivation layer contains PEAI in its material; The electron transport layer is made of PCBM.

2. The perovskite solar cell as described in claim 1, characterized in that, The conductive substrate layer is selected from any one of ITO, FTO, and AZO; The hole transport layer is made of at least one of 4PADCB, CuI, CuSCN, PEDOT:PSS, and PTAA. The material of the hole-side interface modification layer is at least one of Al2O3, SiO2, ZrO2, HfO2, and MgO; The perovskite light-absorbing layer material is APbX3, wherein A is at least one of methylamine, formamidinium, and cesium, and X is at least one of chlorine, bromine, and iodine; The passivation layer is made of PEAI and EDAI2; the hole blocking layer is made of C. 60 C 70 ICBA, PC 61 BM, PC 71 At least one of BM, ZnO, and SnO2; The material of the protective layer is at least one of SnO2, ZnO, Al2O3, and HfO2; The material of the metal electrode layer is at least one of Ag, Au, Cu, and Al.

3. A method for preparing a perovskite solar cell as described in any one of claims 1 to 2, characterized in that, Includes the following steps: A hole transport layer, a hole side interface modification layer, and a perovskite light absorption layer are sequentially prepared on a conductive substrate layer. A solution containing PEAI was prepared to obtain a PEAI solution; the PEAI solution was coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer; Prepare a solution containing triphenyl isocyanate thiophosphate to obtain a triphenyl isocyanate thiophosphate solution. A triphenyl isocyanate thiophosphate solution is coated onto the surface of the passivation layer, or the passivation layer is immersed in a triphenyl isocyanate thiophosphate solution to form a multifunctional crosslinked modified layer on the surface of the passivation layer. Prepare a solution containing PCBM to obtain a PCBM solution; The PCBM solution was coated onto the surface of the multifunctional crosslinked modified layer and annealed to obtain the electron transport layer. A hole blocking layer, a protective layer, and a metal electrode layer are sequentially fabricated on the electron transport layer to obtain a perovskite solar cell.

4. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, Triphenyl isocyanate thiophosphate was added to ethyl acetate to prepare a solution of triphenyl isocyanate thiophosphate with a concentration of 0.01~2 mg / mL. A triphenyl isocyanate solution of thiophosphate was spin-coated onto the surface of the passivation layer, wherein the spin-coating speed was 4000~4500 r / min and the spin-coating time was 30~60 s; The passivation layer is immersed in a solution of triphenyl isocyanate thiophosphate for 1 to 60 seconds.

5. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, PEAI and EDAI2 are added to isopropanol to obtain a PEAI solution; the concentration of PEAI in the PEAI solution is 1~2 mg / mL and the concentration of EDAI2 is 0.5~1 mg / mL. PEAI solution was spin-coated onto the surface of the perovskite light-absorbing layer and annealed to obtain a passivation layer. The spin-coating speed was 4000~4500 r / min, the spin-coating time was 30~60 s, and the annealing temperature was 100~110℃ for 5~10 min.

6. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, PCBM is added to chlorobenzene to obtain a PCBM solution; the concentration of PCBM in the PCBM solution is 10~15 mg / mL; The PCBM solution was spin-coated onto the surface of the multifunctional crosslinked modified layer and then annealed to obtain the electron transport layer. The spin-coating speed was 7000~8000 r / min, the spin-coating time was 30~60s, and the annealing temperature was 75~85℃ for 5~10min.

7. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, The perovskite light-absorbing layer material is FA. 0.95 Cs 0.05 PbI3; The perovskite light-absorbing layer is prepared by adding CsI, FAI, PbI2, and MACl to a solvent to obtain a perovskite precursor solution. The perovskite precursor solution was spin-coated onto the surface of the hole-side interface modification layer and annealed to obtain the perovskite light-absorbing layer. The spin-coating speed was 2000~4000 r / min, the spin-coating time was 10~60s, and chlorobenzene was added during spin-coating. The annealing temperature was 100~110℃ and the time was 30~35 min.

8. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, The hole transport layer material is 4PADCB, and the method for preparing the hole transport layer is as follows: 4PADCB was added to ethanol to obtain a 4PADCB solution with a concentration of 0.5~1 mg / mL; A 4PADCB solution was spin-coated onto the surface of a conductive substrate and then annealed to obtain a hole transport layer. The spin-coating speed was 3000~4000 r / min and the spin-coating time was 30~60s. The annealing temperature was 100~110℃ and the annealing time was 10~15 min.

9. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, The material of the hole-side interface modification layer is Al2O3; Al2O3 was added to isopropanol to obtain an Al2O3 solution with a concentration of 0.02~1 mg / mL; Al2O3 solution was spin-coated onto the surface of the hole transport layer and annealed to obtain a hole-side interface modification layer. The spin-coating speed was 5000~5500 r / min and the spin-coating time was 30~60s. The annealing temperature was 100~110℃ and the annealing time was 5~10 min.

10. The method for preparing a perovskite solar cell as described in claim 3, characterized in that, A hole-blocking layer was prepared on the surface of the electron transport layer by thermal evaporation, wherein the evaporation rate was 0.05~0.1 Å / s; A protective layer was deposited on the surface of the hole-blocking layer using atomic layer deposition (ALD). A metal electrode layer was prepared on the surface of the protective layer by thermal evaporation, wherein the evaporation rate was 0.1~1 Å / s.

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