Hole-transport-layer-free perovskite solar cell based on copper halide chelate additive and preparation method of hole-transport-layer-free perovskite solar cell

Abstract

The invention relates to a hole transport layer-free perovskite solar cell based on a copper halide chelate additive and a preparation method thereof, and the perovskite solar cell comprises a transparent conductive substrate layer, a perovskite light absorption layer, an electron transport layer, an interface buffer layer and an electrode layer from bottom to top. Wherein the perovskite light absorption layer contains a copper halide chelate additive. The structural general formula of the copper halide chelate is M.N, M is copper halide, and N is a thioamide compound. The growth process of the perovskite thin film is accurately regulated and controlled by adopting the copper halide chelate additive, a gradient energy band structure beneficial to interface charge transmission is constructed, hole migration at the perovskite and the transparent conductive substrate is enhanced, transmission of holes from a perovskite layer to a transparent electrode is accelerated, carrier non-radiative recombination is effectively inhibited, and the performance of the perovskite thin film is improved. Finally, the perovskite solar cell which is simple in structure and excellent in performance is prepared, and a new solution is provided for the development of the hole-free pure transport layer perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a perovskite solar cell without a hole transport layer based on a copper halide chelate additive and a preparation method thereof. Background Art

[0002] As a promising photovoltaic material, organometallic halide perovskites have attracted a global research boom in recent years due to their significant advantages such as low exciton binding energy, long carrier lifetime, high light absorption capacity and adjustable band gap. In recent years, great progress has been made in the research of inverted perovskite solar cells, and the efficiency has climbed to 26.7%. However, the hole transport efficiency has a great influence on the performance of inverted perovskite solar cell devices. At present, the stability and amplification preparation process of inverted perovskite devices are limited by the hole transport layer. Commonly used hole transport layer materials can be divided into organic and inorganic materials. Organic hole transport materials such as [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz) are expensive and have poor conductivity. Their hydrophobic properties make it difficult to evenly coat the perovskite solution on their surface, and they may degrade under light and high temperature conditions. Inorganic hole transport materials such as nickel oxide often require relatively high annealing temperatures to achieve high-quality crystallization and high hole transport efficiency. In addition, there is an interface degradation reaction between nickel oxide and perovskite, which is not conducive to the long-term stable operation of the device.

[0003] In order to solve the shortcomings of hole transport layer materials, the prior art proposes a technical solution without a hole transport layer. The main method is to remove the hole transport layer between the transparent conductive oxide and the perovskite, resulting in direct contact between the transparent conductive oxide and the perovskite, forming a Schottky contact barrier, and defects in the contact interface produce a Fermi pinning effect, causing the loss zone and the energy band to bend downward, hindering the effective transmission of holes; at the same time, the removal of the hole transport layer causes the interface contact to lose selectivity, aggravating the voltage reduction of the non-radiative composite conductive perovskite battery of electrons and holes.

[0004] Selecting appropriate p-type hole transport layer materials to add to the perovskite precursor solution to prepare a composite perovskite solution, and developing a rapid preparation method for perovskite solar cell devices without a hole transport layer are crucial to achieving efficient, stable, and low-cost perovskite solar cells. Although attempts have been made to use p-type semiconductor molecules such as CuSCN, CuCl, and Cu(Tu)I to dope perovskite precursor solutions to prepare perovskite cells without a hole transport layer, their photoelectric conversion efficiency is still lower than that of perovskite solar cells with a complete structure. This is mainly because the work function mismatch between the perovskite and transparent conductive oxide electrode interfaces makes it difficult to effectively extract holes and the charge recombination problem is serious. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide a perovskite solar cell without a hole transport layer based on a copper halide chelate additive and a preparation method thereof. The copper halide chelate molecules are squeezed out from a precursor solution to the perovskite grain boundary and the bottom of the film, thereby achieving P-type doping of the buried interface perovskite film, improving the interface hole extraction and transmission capabilities, and improving the film-forming quality of the perovskite light-absorbing layer, thereby greatly improving the efficiency, stability and process reproducibility of the perovskite solar cell without a hole transport layer.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: as a first aspect, a hole transport layer-free perovskite solar cell based on a copper halide chelate additive is provided, wherein the perovskite solar cell comprises, from bottom to top, a transparent conductive substrate layer, a perovskite light absorption layer, an electron transport layer, an interface buffer layer and an electrode layer, wherein the perovskite light absorption layer contains a copper halide chelate additive.

[0007] As a second aspect, a method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive is provided, comprising the following steps:

[0008] (1) Synthesis of copper halide chelates;

[0009] (2) dissolving perovskite powder in an organic solvent, stirring and clarifying to form a perovskite precursor solution, so that the concentration of perovskite in the perovskite precursor solution is 0.1 to 3 mol / L; adding a copper halide chelate, dissolving it completely to obtain a perovskite precursor solution containing a copper halide chelate additive, so that the concentration of the copper halide chelate additive in the perovskite precursor solution containing the copper halide chelate additive is 0.001 to 50 mg / mL; coating or printing the perovskite precursor solution containing the copper halide chelate additive on a clean transparent conductive substrate, and obtaining a perovskite light absorbing layer after heat treatment;

[0010] (3) An electron transport layer, an interface buffer layer and an electrode layer are sequentially deposited on the perovskite light absorbing layer to obtain a perovskite solar cell based on a copper halide chelate additive.

[0011] Furthermore, the heat treatment temperature of the perovskite light absorbing layer is 30-300° C., and the time is 3-120 min, preferably 100° C. for 16 min.

[0012] Furthermore, the transparent conductive substrate layer is selected from: FTO (fluorine-doped tin oxide) glass, ITO (tin-doped indium oxide) glass, ITO (tin-doped indium oxide) / PET (ethylene terephthalate), ITO (tin-doped indium oxide) / PEN (polyethylene phthalate), ITO (tin-doped indium oxide) / PI (polyimide); the electron transport layer is fullerene and its derivatives, selected from: C60, C70, PC60M; the interface buffer layer is selected from: bathocuproin, tin oxide, zinc oxide, yttrium oxide, cerium oxide, titanium oxide, niobium oxide; the electrode layer is selected from: Cu, Ag, Au, Mo, ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), AZO (aluminum-doped zinc oxide).

[0013] Furthermore, the general structural formula of the perovskite is ABX3, wherein A is selected from Cs + 、MA + (CH3NH3 + ), FA + [HC(NH2)NH2 + ], B is selected from Pb 2+ Sn 2+ ,Ge 2+ , X is selected from I - Br - , Cl - The general structural formula of the copper halide chelate is M·N, wherein M is a copper halide selected from: CuF, CuCl, CuBr, CuI, CuBF4, CuPF6, and N is a thioamide compound selected from: thiosemicarbazide, 3,4,5,6-tetrahydro-2-pyrimidinethiol, guanylthiourea, thioformyl dihydrazide, thiocaprolactam, thioisonicotinamide, triethylenethiophosphoramide, dithiobiuret, 1,1-thiocarbonyldiimidazole, 1H-indole-4-thioformamide, pyrazine-2-thioamide, pyrimidine-2-carbonthioamide, ethylenethiourea, tetrahydropyrrole-2-thione.

[0014] Preferably, the copper halide chelate is CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol.

[0015] Furthermore, the thickness of the perovskite light-absorbing layer containing the copper halide chelate additive is 100 to 2000 nm; the thickness of the electron transport layer is 1 to 100 nm; the thickness of the interface buffer layer is 1 to 100 nm; and the thickness of the electrode layer is 10 to 10000 nm.

[0016] Furthermore, the electron transport layer is deposited by evaporation; the interface buffer layer is deposited by evaporation, sputtering, reactive plasma deposition, chemical vapor deposition, coating, and printing; the electrode layer is deposited by evaporation, sputtering, chemical vapor deposition, coating, and printing.

[0017] Preferably, the transparent conductive substrate layer is FTO glass; the electron transport layer is C60; the interface buffer layer is tin oxide; and the electrode layer is IZO.

[0018] Preferably, the thickness of the perovskite light-absorbing layer containing the copper halide chelate additive is 530 nm; the thickness of the electron transport layer is 15 nm; the thickness of the interface buffer layer is 10 nm; the thickness of the electrode layer is 400 nm; the electron transport layer is deposited by evaporation; the interface buffer layer is deposited by reactive plasma deposition; and the electrode layer is deposited by sputtering deposition.

[0019] Furthermore, the organic solvent used to prepare the perovskite precursor solution is a mixture of one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-methoxyethanol, acetonitrile, and tetrahydrofuran in any proportion.

[0020] Preferably, the concentration of perovskite in the perovskite precursor solution is 1.45 mol / L; the concentration of the copper halide chelate additive in the perovskite precursor solution containing the copper halide chelate additive is 3.3 mg / mL; the organic solvent used to prepare the perovskite precursor solution is a mixture of acetonitrile, tetrahydrofuran and dimethyl sulfoxide in a volume ratio of 6:1:3.

[0021] The beneficial effects of the present invention are:

[0022] 1. The copper halide chelate material additive selected by the present invention participates in the lattice formation of perovskite, and can play the role of a seed in the perovskite precursor solution to form heterogeneous nucleation sites with large crystal nuclei. These sites can reduce the nucleation free energy of PbI2, and ultimately promote the growth of perovskite crystals, increase the grain size of the perovskite film, make the perovskite film more uniform and dense, improve the quality of the film and reduce grain boundary defects.

[0023] 2. The copper halide chelate interacts strongly with the uncoordinated lead ions in the perovskite. The S and N atoms with lone electron pairs in the molecule can react with the incompletely coordinated Pb with a net positive charge. 2+ Providing electron density accelerates the effective charge transfer between copper halide chelate and perovskite. In addition, the -Cl group, C=S group and amine group in the copper halide chelate molecule can also interact with the perovskite, which is beneficial to fill the shallow energy level iodine vacancy defects generated by the perovskite during the film formation process.

[0024] 3. The present invention utilizes the self-adsorption property of copper halide chelate materials to promote hole transport at the interface between perovskite and transparent conductive substrate and reduce non-radiative recombination, adjust the work function at the interface between perovskite and transparent conductive substrate to make the energy levels more matched, reduce the hole transport energy barrier, and realize the preparation of efficient and stable perovskite cells without hole transport layer.

[0025] 4. The present invention adopts copper halide chelate to prepare non-hole transport perovskite solar cells, which has simple process, low cost and can be scaled up for batch preparation, which is conducive to industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0027] Figure 1 The schematic diagram of the structure of the perovskite solar cell based on the copper halide chelate additive of the present invention;

[0028] Figure 2 This is a SEM image of the perovskite light-absorbing layer with CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive of the present invention;

[0029] Figure 3 It is a steady-state fluorescence spectrum diagram of the perovskite light-absorbing layer with or without the copper halide chelate additive of the present invention.

[0030] In the figure, there is a transparent conductive substrate 1, a perovskite light absorbing layer 2, an electron transport layer 3, an interface buffer layer 4, an electrode layer 5, and a copper halide chelate additive 6. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0032] The idea of ​​the present invention is to use copper halide chelate additives to accurately control the growth process of perovskite film, construct a gradient band structure that is conducive to interface charge transfer, enhance hole migration between perovskite and transparent conductive substrate, accelerate the transmission of holes from the perovskite layer to the transparent electrode, effectively inhibit carrier complex non-radiative recombination, and finally prepare a perovskite solar cell with simple structure and excellent performance, providing a new solution for the development of hole-free pure transport layer perovskite solar cells.

[0033] Embodiment 1:

[0034] like Figure 1 As shown, a perovskite solar cell without a hole transport layer based on a copper halide chelate additive and a preparation method thereof comprises the following steps:

[0035] Step 1: Synthesis of CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol:

[0036] Under a nitrogen atmosphere, a 3,4,5,6-tetrahydro-2-pyrimidinethiol solution (containing 697.08 mg of 3,4,5,6-tetrahydro-2-pyrimidinethiol dissolved in 30 ml of acetonitrile) and a cuprous chloride (CuCl) solution (containing 594 mg of cuprous chloride dissolved in 10 ml of acetonitrile) were mixed and stirred for 1 hour. After the resulting suspension was allowed to stand for 3 days, a CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol solid was precipitated. The CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol solid was filtered and washed three times with acetonitrile and ether in sequence. Finally, a white CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol powder (697 mg, a yield of 54%) was obtained after vacuum drying at 70° C. for 12 hours.

[0037] Step 2: Preparation of a hole transport layer-free perovskite solar cell containing CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive:

[0038] (1) ultrasonically cleaning the FTO glass with a glass cleaning agent, ultrapure water, and alcohol in sequence, and drying after cleaning to obtain a clean FTO glass substrate;

[0039] (2) First, weigh CsI, MAI, FAI, and PbI2 powders (molar ratio of 0.1:0.1:0.8:1.05) and dissolve them in a mixed solvent of acetonitrile, tetrahydrofuran, and dimethyl sulfoxide in a volume ratio of 6:1:3. After stirring to clarify, a 1.45 mol / L perovskite precursor solution was obtained. Subsequently, 3.3 mg of CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol was weighed and added to 1 mL of the perovskite precursor solution. After stirring and dissolving completely, a perovskite precursor solution containing CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive was obtained.

[0040] (3) Slit coating a perovskite precursor solution containing a CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive on a clean FTO glass substrate, and heat treating the coated perovskite wet film at 100°C for 16 min to obtain a perovskite light-absorbing layer with a thickness of 530 nm;

[0041] (4) A 15 nm thick C60 electron transport layer is evaporated on the perovskite light absorbing layer, a 10 nm thick tin oxide interface buffer layer is deposited by reactive plasma, and a 400 nm thick IZO electrode layer is sputtered to obtain a hole transport layer-free perovskite solar cell based on CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive.

[0042] Comparative Example 1:

[0043] A perovskite solar cell without a hole transport layer and a copper halide chelate additive and a preparation method thereof, comprising the following steps:

[0044] (1) ultrasonically cleaning the FTO glass with a glass cleaning agent, ultrapure water, and alcohol in sequence, and drying after cleaning to obtain a clean FTO glass substrate;

[0045] (2) First, weigh CsI, MAI, FAI, and PbI2 powders (molar ratio of 0.1:0.1:0.8:1.05) and dissolve them in a mixed solvent of acetonitrile, tetrahydrofuran, and dimethyl sulfoxide in a volume ratio of 6:1:3. After stirring to clarify, a 1.45 mol / L perovskite precursor solution is obtained. After stirring and dissolving completely, a perovskite precursor solution without a copper halide chelate additive is obtained.

[0046] (3) Slit coating a perovskite precursor solution on a clean FTO glass substrate, and heat treating the coated perovskite wet film at 100°C for 16 min to obtain a perovskite light-absorbing layer with a thickness of 530 nm;

[0047] (4) A 15 nm thick C60 electron transport layer is sequentially evaporated on the perovskite light absorbing layer, a 10 nm thick tin oxide interface buffer layer is reactively plasma deposited, and a 400 nm thick IZO electrode layer is sputtered to obtain a hole transport layer-free perovskite solar cell based on a copper halide chelate additive.

[0048] Comparative Example 2:

[0049] Step 1: Synthesis of CuCl·1,1-thiocarbonyldiimidazole:

[0050] Under a nitrogen atmosphere, a 1,1-thiocarbonyldiimidazole solution (containing 1069.26 mg of 1,1-thiocarbonyldiimidazole dissolved in 30 ml of acetonitrile) and a cuprous chloride (CuCl) solution (containing 594 mg of cuprous chloride dissolved in 10 ml of acetonitrile) were mixed and stirred for 1 hour. After the resulting suspension was allowed to stand for 3 days, CuCl·1,1-thiocarbonyldiimidazole solid precipitated. The CuCl·1,1-thiocarbonyldiimidazole solid was filtered and washed three times with acetonitrile and ether in sequence. Finally, white CuCl·1,1-thiocarbonyldiimidazole powder (1031 mg, yield 62%) was obtained after vacuum drying at 70°C for 12 hours.

[0051] Step 2: Preparation of a hole transport layer-free perovskite solar cell containing CuCl·1,1-thiocarbonyldiimidazole additive:

[0052] (1) ultrasonically cleaning the FTO glass with a glass cleaning agent, ultrapure water, and alcohol in sequence, and drying after cleaning to obtain a clean FTO glass substrate;

[0053] (2) First, weigh CsI, MAI, FAI, and PbI2 powders (molar ratio of 0.1:0.1:0.8:1.05) and dissolve them in a mixed solvent of acetonitrile, tetrahydrofuran, and dimethyl sulfoxide in a volume ratio of 6:1:3. After stirring to clarify, a 1.45 mol / L perovskite precursor solution was obtained. Subsequently, 3.3 mg of CuCl·1,1-thiocarbonyldiimidazole was weighed and added to 1 mL of the perovskite precursor solution. After stirring and dissolving completely, a perovskite precursor solution containing CuCl·1,1-thiocarbonyldiimidazole additive was obtained.

[0054] (3) Slit coating a perovskite precursor solution containing a CuCl·1,1-thiocarbonyldiimidazole additive on a clean FTO glass substrate, and heat treating the coated perovskite wet film at 100°C for 16 min to obtain a perovskite light-absorbing layer with a thickness of 530 nm;

[0055] (4) A 15 nm thick C60 electron transport layer is sequentially evaporated on the perovskite light absorbing layer, a 10 nm thick tin oxide interface buffer layer is reactively plasma deposited, and a 400 nm thick IZO electrode layer is sputtered to obtain a hole transport layer-free perovskite solar cell based on CuCl·1,1-thiocarbonyldiimidazole additive.

[0056] Comparative Example 3:

[0057] Step 1: Synthesis of CuCl·triethylenethiophosphoramide:

[0058] Under a nitrogen atmosphere, a triethylene thiophosphoramide solution (containing 1135.32 mg of triethylene thiophosphoramide dissolved in 30 ml of acetonitrile) and a cuprous chloride (CuCl) solution (containing 594 mg of cuprous chloride dissolved in 10 ml of acetonitrile) were mixed and stirred for 1 hour. After the resulting suspension was allowed to stand for 3 days, a CuCl·triethylene thiophosphoramide solid was precipitated. The CuCl·triethylene thiophosphoramide solid was filtered and washed three times with acetonitrile and ether in sequence. Finally, a white CuCl·triethylene thiophosphoramide powder (830 mg, 48% yield) was obtained after vacuum drying at 70° C. for 12 hours.

[0059] Step 2: Preparation of a hole transport layer-free perovskite solar cell containing a CuCl·triethylene thiophosphoramide additive:

[0060] (1) ultrasonically cleaning the FTO glass with a glass cleaning agent, ultrapure water, and alcohol in sequence, and drying after cleaning to obtain a clean FTO glass substrate;

[0061] (2) First, weigh CsI, MAI, FAI, and PbI2 powders (molar ratio of 0.1:0.1:0.8:1.05) and dissolve them in a mixed solvent of acetonitrile, tetrahydrofuran, and dimethyl sulfoxide in a volume ratio of 6:1:3. After stirring to clarify, a 1.45 mol / L perovskite precursor solution was obtained. Subsequently, 3.3 mg of triethylene thiophosphoramide was weighed and added to 1 mL of the perovskite precursor solution. After stirring and dissolving completely, a perovskite precursor solution containing CuCl·triethylene thiophosphoramide additive was obtained.

[0062] (3) Slit coating a perovskite precursor solution containing a CuCl·triethylene thiophosphoramide additive on a clean FTO glass substrate, and heat treating the coated perovskite wet film at 100°C for 16 min to obtain a perovskite light-absorbing layer with a thickness of 530 nm;

[0063] (4) A 15 nm thick C60 electron transport layer is sequentially evaporated on the perovskite light absorbing layer, a 10 nm thick tin oxide interface buffer layer is reactively plasma deposited, and a 400 nm thick IZO electrode layer is sputtered to obtain a hole transport layer-free perovskite solar cell based on CuCl·triethylene thiophosphoramide additive.

[0064] Comparative Example 4:

[0065] Step 1: Synthesis of CuCl·thioformyl dihydrazide:

[0066] Under a nitrogen atmosphere, a thioformyl dihydrazide solution (containing 636.9 mg of thioformyl dihydrazide dissolved in 30 ml of acetonitrile) and a cuprous chloride (CuCl) solution (containing 594 mg of cuprous chloride dissolved in 10 ml of acetonitrile) were mixed and stirred for 1 hour. After the resulting suspension was allowed to stand for 3 days, a CuCl·thioformyl dihydrazide solid was precipitated. The CuCl·thioformyl dihydrazide solid was filtered and washed three times with acetonitrile and ether in sequence. Finally, a white CuCl·thioformyl dihydrazide powder (837 mg, 68% yield) was obtained after vacuum drying at 70° C. for 12 hours.

[0067] Step 2: Preparation of a hole transport layer-free perovskite solar cell containing a CuCl·thioformyl dihydrazide additive:

[0068] (1) ultrasonically cleaning the FTO glass with a glass cleaning agent, ultrapure water, and alcohol in sequence, and drying after cleaning to obtain a clean FTO glass substrate;

[0069] (2) First, weigh CsI, MAI, FAI, and PbI2 powders (molar ratio of 0.1:0.1:0.8:1.05) and dissolve them in a mixed solvent of acetonitrile, tetrahydrofuran, and dimethyl sulfoxide in a volume ratio of 6:1:3. After stirring to clarify, a 1.45 mol / L perovskite precursor solution was obtained. Subsequently, 3.3 mg of CuCl·thioformyl dihydrazide was weighed and added to 1 mL of the perovskite precursor solution. After stirring and dissolving completely, a perovskite precursor solution containing CuCl·thioformyl dihydrazide additive was obtained.

[0070] (3) Slit coating a perovskite precursor solution containing a CuCl·thioformyl dihydrazide additive on a clean FTO glass substrate, and heat treating the coated perovskite wet film at 100°C for 16 min to obtain a perovskite light-absorbing layer with a thickness of 530 nm;

[0071] (4) A 15 nm thick C60 electron transport layer is sequentially evaporated on the perovskite light absorbing layer, a 10 nm thick tin oxide interface buffer layer is reactively plasma deposited, and a 400 nm thick IZO electrode layer is sputtered to obtain a hole transport layer-free perovskite solar cell based on CuCl·thioformyl dihydrazide additive.

[0072] As shown in Table 1, the photoelectric conversion efficiency of the hole transport layer-free perovskite solar cell prepared with the CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive is as high as 25.14%, and the efficiency of the cell only decays by 1.4% after 1000 hours of maximum power point tracking. The device efficiency and stability are much better than those of other comparative devices, indicating that the CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol additive can significantly improve the efficiency and stability of the hole transport layer-free perovskite cell.

[0073] Figure 2 The perovskite film with the addition of CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol has a large grain size, high phase purity and crystallinity, retains a good crystal structure, and the quality of the perovskite film is significantly improved. Since the doping amount of copper halide chelate is relatively small, it does not destroy the original structure of the perovskite, but instead becomes more stable.

[0074] like Figure 3 As shown, the steady-state fluorescence test was used to further evaluate that the band gap of the perovskite did not change after the addition of CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol, and the fluorescence intensity was relatively high, indicating that CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol has an excellent defect passivation effect, which can effectively increase the charge carrier lifetime and reduce the charge carrier recombination.

[0075] Table 1. Performance parameters of the devices in the examples and comparative examples

[0076]

[0077]

[0078] The above description is only a preferred experimental example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A perovskite solar cell without a hole transport layer based on a copper halide chelate additive, characterized in that: The perovskite solar cell comprises a transparent conductive substrate layer, a perovskite light-absorbing layer, an electron transport layer, an interface buffer layer and an electrode layer from bottom to top, wherein the perovskite light-absorbing layer contains a copper halide chelate additive.

2. A method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive as claimed in claim 1, characterized in that: The following steps are involved: (1) Synthesis of copper halide chelates; (2) dissolving perovskite powder in an organic solvent, stirring and clarifying to form a perovskite precursor solution, so that the concentration of perovskite in the perovskite precursor solution is 0.1 to 3 mol / L; adding a copper halide chelate, dissolving it completely to obtain a perovskite precursor solution containing a copper halide chelate additive, so that the concentration of the copper halide chelate additive in the perovskite precursor solution containing the copper halide chelate additive is 0.001 to 50 mg / mL; coating or printing the perovskite precursor solution containing the copper halide chelate additive on a clean transparent conductive substrate, and obtaining a perovskite light absorbing layer after heat treatment; (3) An electron transport layer, an interface buffer layer and an electrode layer are sequentially deposited on the perovskite light absorbing layer to obtain a perovskite solar cell based on a copper halide chelate additive.

3. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The heat treatment temperature of the perovskite light absorbing layer is 30-300° C., and the time is 3-120 minutes.

4. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The transparent conductive substrate layer is selected from: FTO glass, ITO glass, ITO / PET, ITO / PEN, ITO / PI; the electron transport layer is fullerene and its derivatives, selected from: C60, C70, PC60M; the interface buffer layer is selected from: bathocuproin, tin oxide, zinc oxide, yttrium oxide, cerium oxide, titanium oxide, niobium oxide; the electrode layer is selected from: Cu, Ag, Au, Mo, ITO, IZO, AZO.

5. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The general structural formula of the perovskite is ABX3, wherein A is selected from Cs + 、MA + , FA + , B is selected from Pb 2+ Sn 2+ ,Ge 2+ , X is selected from I - Br - , Cl - The general structural formula of the copper halide chelate is M·N, wherein M is a copper halide selected from: CuF, CuCl, CuBr, CuI, CuBF4, CuPF6, and N is a thioamide compound selected from: thiosemicarbazide, 3,4,5,6-tetrahydro-2-pyrimidinethiol, guanylthiourea, thioformyl dihydrazide, thiocaprolactam, thioisonicotinamide, triethylenethiophosphoramide, dithiobiuret, 1,1-thiocarbonyldiimidazole, 1H-indole-4-thioformamide, pyrazine-2-thioamide, pyrimidine-2-carbonthioamide, ethylenethiourea, tetrahydropyrrole-2-thione.

6. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The thickness of the perovskite light-absorbing layer containing the copper halide chelate additive is 100 to 2000 nm; the thickness of the electron transport layer is 1 to 100 nm; the thickness of the interface buffer layer is 1 to 100 nm; and the thickness of the electrode layer is 10 to 10000 nm.

7. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The electron transport layer is deposited by evaporation; The deposition methods of the interface buffer layer include: evaporation, sputtering, reactive plasma deposition, chemical vapor deposition, coating, and printing; the deposition methods of the electrode layer include: evaporation, sputtering, chemical vapor deposition, coating, and printing.

8. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to any one of claims 4 to 7, characterized in that: The transparent conductive substrate layer is FTO glass; the electron transport layer is C60; the interface buffer layer is tin oxide; the electrode layer is IZO; the thickness of the perovskite light absorption layer containing the copper halide chelate additive is 530nm; the thickness of the electron transport layer is 15nm; the thickness of the interface buffer layer is 10nm; the thickness of the electrode layer is 400nm; the electron transport layer is deposited by evaporation; the interface buffer layer is deposited by reactive plasma deposition; the electrode layer is deposited by sputtering deposition; the copper halide chelate is CuCl·3,4,5,6-tetrahydro-2-pyrimidinethiol.

9. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2, characterized in that: The organic solvent used for preparing the perovskite precursor solution is a mixture of one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-methoxyethanol, acetonitrile and tetrahydrofuran in any proportion.

10. The method for preparing a perovskite solar cell without a hole transport layer based on a copper halide chelate additive according to claim 2 or 9, characterized in that: The concentration of perovskite in the perovskite precursor solution is 1.45 mol / L; the concentration of the copper halide chelate additive in the perovskite precursor solution containing the copper halide chelate additive is 3.3 mg / mL; the organic solvent used to prepare the perovskite precursor solution is a mixture of acetonitrile, tetrahydrofuran and dimethyl sulfoxide in a volume ratio of 6:1:3.

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