Bismuth-based perovskite type solar cell and preparation method thereof

Abstract

The invention belongs to the technical field of perovskite cells, and particularly relates to a formal bismuth-based perovskite solar cell based on a hypophosphorous acid additive and a preparation method of the formal bismuth-based perovskite solar cell. The invention provides a formal bismuth-based perovskite solar cell preparation method based on a hypophosphorous acid additive. A hypophosphorous acid additive is introduced into a precursor solution, Ag NPs can be generated in situ, and the light absorption capacity of the thin film can be enhanced by utilizing the LSPR effect of the Ag NPs. Meanwhile, the additive can promote nucleation, optimize crystal growth and improve crystallinity in the film crystallization process, so that the bismuth-based light absorption layer film which is high in quality, low in defect density and excellent in carrier transport performance is prepared, the surface appearance and the photoelectric property of the bismuth-based perovskite type light absorption layer film can be remarkably improved, and the photoelectric performance of the bismuth-based perovskite type light absorption layer film is improved. The defect density is reduced, and non-radiative recombination is inhibited, so that the generation, separation and transmission efficiency of photo-generated charges is greatly improved, and finally the photoelectric conversion efficiency of the bismuth-based perovskite solar cell is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cells, and in particular relates to a formal-structured bismuth-based perovskite solar cell based on hypophosphorous acid additive and a preparation method thereof. Background Art

[0002] Under the background of the rapid growth of global energy demand and the increasing environmental pressure, the development of efficient, environmentally friendly and cost-controllable solar cell technologies has become a key direction for the development of renewable energy. Among various photovoltaic technologies, perovskite solar cells have attracted much attention in recent years due to their excellent photoelectric conversion efficiency, solution-processable characteristics and potential for low-cost manufacturing.

[0003] Since the first report in 2009, the photoelectric conversion efficiency of perovskite solar cells has increased from less than 4% to 26% under laboratory conditions, demonstrating great market potential. However, the synthesis of high-efficiency perovskite materials still highly depends on lead (such as methylammonium lead iodide CH 3 NH 3 PbI 3 ), and its toxicity and potential risks to the environment and health have restricted its commercialization and large-scale application.

[0004] In the exploration of non-lead alternative materials, bismuth (Bi)-based perovskites and their derivatives are regarded as potential candidates due to their excellent environmental stability, high absorption coefficient, suitable ionic radius and Pb 2+ -like electronic properties. Nevertheless, the photoelectric conversion efficiency of solar cells based on bismuth-based perovskite light-absorbing layers is still lower than that of lead-based perovskites, mainly due to the low crystallinity, poor morphology and more defects of the synthesized bismuth-based perovskite thin films, which limit their practical applications. Summary of the Invention

[0005] One of the objectives of the present invention is to provide a bismuth-based perovskite solar cell. Hypophosphorous acid is used as an additive and added to the bismuth-based perovskite light-absorbing layer, which can in-situ generate Ag NPs and utilize its LSPR effect to enhance the light absorption ability of the thin film. At the same time, this additive can promote nucleation during the crystallization process of the thin film, optimize crystal growth and improve crystallinity, thereby preparing a high-quality, low-defect-density bismuth-based light-absorbing layer thin film with excellent carrier transport performance, and ultimately improving the photoelectric conversion efficiency of the bismuth-based perovskite solar cell.

[0006] To achieve the above objective, the present invention adopts the following technical solution: A bismuth-based perovskite solar cell, in which hypophosphorous acid is used as an additive and added to the bismuth-based perovskite light-absorbing layer.

[0007] As a further improvement of the bismuth-based perovskite solar cell:

[0008] Preferably, the bismuth-based perovskite solar cell sequentially includes, from bottom to top: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode.

[0009] Preferably, the transparent conductive substrate is ITO or FTO; the electron transport layer is SnO 2 ; the hole transport layer is Spiro-OMeTAD; the metal electrode is Ag, Au, Al, or Cu; the bismuth-based perovskite light-absorbing layer is a bismuth-based double perovskite derivative, and the chemical formula of the composition is Cu 2 AgBiI 6 and CuAgBiI 5 .

[0010] The second object of the present invention is to provide a preparation method of the bismuth-based perovskite solar cell described in any one of the above, including the following steps:

[0011] Step 1: Clean the transparent conductive substrate to obtain a clean surface; coat the SnO 2 particle dispersion on the clean transparent conductive substrate and anneal to prepare the electron transport layer;

[0012] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor material in a mixed solvent of DMSO and DMF, heat and stir, then filter, add a hypophosphorous acid additive to the filtrate, and react to obtain a light-absorbing layer precursor solution;

[0013] Spin-coat the light-absorbing layer precursor solution on the electron transport layer and anneal to prepare the bismuth-based perovskite light-absorbing layer;

[0014] Step 3: Dissolve the hole transport layer material in chlorobenzene, mix well, and then drop it onto the bismuth-based perovskite light-absorbing layer and spin-coat to prepare the hole transport layer;

[0015] Step 4: Under high vacuum conditions, evaporate the metal electrode on the hole transport layer to obtain the bismuth-based perovskite solar cell with a complete formal structure.

[0016] As a further improvement of the preparation method of the bismuth-based perovskite solar cell:

[0017] Preferably, in step 1, the transparent conductive substrate is ultrasonically cleaned successively with a detergent, ultrapure water, acetone, and isopropanol, then dried with nitrogen, and treated with an ultraviolet ozone cleaner to obtain a clean surface.

[0018] Preferably, in step 1, SnO 2The concentration of the particle dispersion is 5-12%, the spin coating speed is 3000-6000 rpm, the time is 30-45 s, the spin coating thickness is 10-100 nm, the annealing temperature is 100-150 °C, and the time is 20-30 min.

[0019] Preferably, in step 2, the bismuth-based perovskite light-absorbing layer material is cuprous halide salt, silver halide salt and bismuth halide salt, and the volume ratio of DMSO to DMF is (2-4):1; the dissolution concentration of the bismuth-based perovskite light-absorbing layer precursor material in the mixed solvent is 0.3-0.5 M.

[0020] Preferably, in step 2, the temperature of heating and stirring is 100-150 °C, and the time is 0.5-1 h; the addition amount of hypophosphorous acid additive in the filtrate is 0.15-0.50 vol%; the spin coating speed of the light-absorbing layer precursor solution on the electron transport layer is 3000-6000 rpm, the time is 45-60 s, and the spin coating thickness is 200-300 nm; first pre-anneal at 40-50 °C for 40-50 min, and then anneal at 100-150 °C for 3-5 min to obtain the bismuth-based perovskite light-absorbing layer.

[0021] Preferably, in step 3, the dissolution concentration of the hole transport layer material in chlorobenzene is 50-100 mg / mL, the spin coating speed is 3000-4000 rpm, the time is 30-45 s, and the spin coating thickness is 50-100 nm.

[0022] Preferably, in step 4, the thickness of the metal electrode is 100-150 nm.

[0023] The beneficial effects of the present invention compared with the prior art are as follows:

[0024] 1. Based on the bismuth-based perovskite light-absorbing layer - copper-silver-bismuth-iodine system (Cu-Ag-Bi-I) with excellent optoelectronic properties, the present invention proposes a strategy to improve the performance of lead-free Cu 3 PO 2 ) by introducing hypophosphorous acid (H 2 AgBiI 6 and CuAgBiI 5 solar cells. Among them, H 3 PO 2 has a dual function in the Cu 2 AgBiI 6 precursor solution: on the one hand, the in-situ generation of silver nanoparticles (Ag NPs) is induced by its reducing ability, and the local surface plasmon resonance (LSPR) effect of Ag NPs can effectively enhance the light absorption ability of the thin film; on the other hand, H 3 PO 2 is oxidized to form phosphorous acid (H 3 PO3 ) and form a coordination interaction with Bi 3+ ions, effectively passivating the bismuth metal (Bi 0 ) defects and improving the film crystallization quality. Through this additive strategy, the surface morphology and optoelectronic properties of the bismuth-based perovskite light-absorbing layer film can be significantly improved, the defect density can be reduced, and non-radiative recombination can be inhibited, thereby greatly enhancing the generation, separation, and transport efficiency of photo-generated charges. In addition, this strategy also demonstrates good universality and high efficiency in the CuAgBiI 5 system. Based on the optimized Cu 2 AgBiI 6 and CuAgBiI 5 solar cells, their power conversion efficiency (PCE) both reaches 1.02%. This research provides a new idea for improving the performance of lead-free perovskite solar cells and promotes their further development in the field of environmental-friendly photovoltaic technology. The method for preparing the bismuth-based perovskite solar cell of the present invention has the characteristics of simple process, low cost, and environmental friendliness.

[0025] 2. By introducing hypophosphorous acid additive into the precursor solution of the bismuth-based perovskite light-absorbing layer, silver nanoparticles can be in-situ generated, and the light absorption of the light-absorbing layer can be significantly enhanced by using the local surface plasmon resonance (LSPR) effect, thereby improving the photocurrent of the device. The hypophosphorous acid additive can effectively regulate the nucleation process of the bismuth-based light-absorbing layer and delay the crystallization rate, thereby improving the film grain size and uniformity, reducing non-radiative recombination at grain boundaries, and further enhancing the separation and transport efficiency of photo-generated charges in the light-absorbing layer. Hypophosphorous acid can be oxidized to phosphorous acid in the precursor solution and form a coordination interaction with Bi 3+ to effectively passivate Bi 0 defects, reduce non-radiative recombination and defect state density, and further improve the carrier transport efficiency and built-in electric field of the light-absorbing layer. Brief Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of the bismuth-based perovskite solar cell with the formal structure of the present invention;

[0027] Figure 2 is the current density-voltage characteristic curve of the formal bismuth-based perovskite Cu 2 AgBiI 6 solar cell prepared in Comparative Example 1;

[0028] Figure 3 is the current density-voltage characteristic curve of the formal bismuth-based perovskite Cu 2 AgBiI 6 solar cell prepared in Example 1;

[0029] Figure 4For the formal bismuth-based perovskite CuAgBiI prepared in Comparative Example 2 5 Current density-voltage characteristic curve of the solar cell;

[0030] Figure 5 For the formal bismuth-based perovskite CuAgBiI prepared in Example 2 5 Current density-voltage characteristic curve of the solar cell. Detailed implementation manners

[0031] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention is provided in conjunction with the embodiments. The following content is only an example and illustration of the concept of the present invention. Those skilled in the art of the present technology can modify, supplement or use similar methods to replace the specific embodiments according to the actual situation. As long as it does not deviate from the concept of the invention or exceed the scope defined by the claims of the present invention, it should be regarded as the protection scope of the present invention.

[0032] Comparative Example 1

[0033] This comparative example provides a bismuth-based perovskite solar cell, as Figure 1 shown, which sequentially includes from bottom to top: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode.

[0034] This bismuth-based perovskite Cu 2 AgBiI 6 The preparation method of the solar cell includes the following steps:

[0035] Step 1: The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then subjected to ultraviolet ozone cleaning treatment for 15 min to obtain a clean surface;

[0036] Take a SnO 2 particle dispersion with a dispersion concentration of 5 wt%, coat it on the clean transparent conductive substrate, and anneal it to obtain an electron transport layer, which is transferred to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min;

[0037] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF. The volume ratio of DMSO to DMF is 3:1. The concentration of CuI added to the mixed solvent is 119.1 mg mL -1 , the concentration of AgI is 120.9 mg mL -1 , BiI 3Concentration: 258.6 mg / mL -1 ; After heating and stirring, filter. The temperature for heating and stirring is 100 °C and the time is 1 h to obtain a bismuth-based perovskite-type Cu 2 AgBiI 6 precursor solution;

[0038] Spin-coat the precursor solution on the electron transport layer at a speed of 3000 rpm for 60 s. The spin-coating thickness is 270 nm. First, pre-anneal at 50 °C for 50 min, and then anneal at 150 °C for 3 min to prepare a bismuth-based perovskite-type light-absorbing layer.

[0039] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene. After mixing evenly, drop it onto the bismuth-based perovskite-type light-absorbing layer and spin-coat it at a speed of 3000 rpm for 30 s to prepare a hole transport layer;

[0040] Step 4: Under high vacuum (10 -4 Pa), evaporate an Ag electrode with a thickness of 100 nm on the hole transport layer by thermal evaporation method to obtain a bismuth-based perovskite-type solar cell with a complete formal structure.

[0041] Figure 2 The current density-voltage characteristic curve of the bismuth-based perovskite-type Cu 2 AgBiI 6 solar cell prepared in Comparative Example 1 is as follows. The test conditions are as follows: room temperature, atmospheric environment, light condition is AM 1.5G simulated sunlight, and light irradiation intensity is 100 mW / cm -2 . It can be seen that the V OC of the cell obtained in Comparative Example 1 is 0.63 V, and the J SC is 1.54 mA / cm -2 , and the PCE is 0.55%.

[0042] Example 1

[0043] This example provides a bismuth-based perovskite-type solar cell. As Figure 1 shown, from bottom to top in structure, it successively includes: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite-type light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite-type light-absorbing layer.

[0044] The preparation method of this formal bismuth-based perovskite-type Cu 2 AgBiI 6 solar cell includes the following steps:

[0045] Step 1: The ITO conductive glass was ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then treated with ultraviolet ozone cleaning for 15 min to obtain a clean surface;

[0046] Take a SnO particle dispersion with a dispersion concentration of 5 wt%, coat it on the clean transparent conductive substrate, and anneal it to prepare an electron transport layer, which is transferred to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min; 2

[0047] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF with a volume ratio of DMSO to DMF of 3:1. Add CuI to the mixed solvent at a concentration of 119.1 mg / mL -1 , AgI at a concentration of 120.9 mg / mL -1 , and BiI 3 at a concentration of 258.6 mg / mL -1 ; filter after heating and stirring. The temperature of heating and stirring is 100 °C and the time is 1 h. Add hypophosphorous acid with a concentration of 0.25 vol% to the filtrate and react for 3 h to obtain a bismuth-based perovskite Cu 2 AgBiI 6 precursor solution;

[0048] Spin-coat the precursor solution on the electron transport layer at a speed of 3000 rpm for 60 s, with a spin coating thickness of 270 nm. First, pre-anneal at 50 °C for 50 min, and then anneal at 150 °C for 3 min to prepare a bismuth-based perovskite light-absorbing layer.

[0049] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene, mix well, and then drop it onto the bismuth-based perovskite light-absorbing layer and spin-coat it at a speed of 3000 rpm for 30 s to prepare a hole transport layer;

[0050] Step 4: Under high vacuum (10 -4 Pa), deposit a 100-nm-thick Ag electrode on the hole transport layer by thermal evaporation method, and then a bismuth-based perovskite solar cell with a complete formal structure is prepared.

[0051] Figure 3 For the formal bismuth-based perovskite Cu 2 AgBiI 6 ​Current density-voltage characteristic curve of the solar cell, with the following test conditions: room temperature, atmospheric environment, illumination condition is AM 1.5G simulated sunlight, and light irradiation intensity is 100 mW / cm² -2 . It can be seen that the V OC of the battery obtained in Example 1 is 0.66 V, and the J SC is 2.97 mA / cm² -2 , and the PCE is 1.02%.

[0052] Comparing Example 1 with Comparative Example 1, it can be seen that after adding hypophosphorous acid, the short-circuit current density of the battery increases significantly, thereby improving the photoelectric conversion efficiency of the battery.

[0053] Example 2

[0054] This example provides a bismuth-based perovskite solar cell, as shown Figure 1 . Structurally, from bottom to top, it successively includes: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite light-absorbing layer.

[0055] The preparation method of this formal bismuth-based perovskite Cu 2 AgBiI 6 solar cell includes the following steps:

[0056] Step 1: The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then treated with ultraviolet ozone cleaning for 15 min to obtain a clean surface;

[0057] Take a SnO 2 particle dispersion solution with a dispersion concentration of 5 wt%, coat it on the clean transparent conductive substrate, and anneal to prepare the electron transport layer, and transfer it to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min;

[0058] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF. The volume ratio of DMSO to DMF is 3:1. The concentration of CuI added in the mixed solvent is 119.1 mg / mL -1 , the concentration of AgI is 120.9 mg / mL -1 , and the concentration of BiI 3 is 258.6 mg / mL -1; After heating and stirring, filter. The temperature for heating and stirring is 100 °C and the time is 1 h. Add hypophosphorous acid with a concentration of 0.15 vol% to the filtrate and react for 3 h to obtain a bismuth-based perovskite-type Cu 2 AgBiI 6 precursor solution;

[0059] Spin-coat the precursor solution on the electron transport layer at a speed of 3000 rpm for 60 s. The spin-coating thickness is 270 nm. First, pre-anneal at 50 °C for 50 min, and then anneal at 150 °C for 3 min to obtain a bismuth-based perovskite-type light-absorbing layer.

[0060] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene. After mixing evenly, drop it onto the bismuth-based perovskite-type light-absorbing layer and spin-coat at a speed of 3000 rpm for 30 s to obtain a hole transport layer;

[0061] Step 4: Under high vacuum (10 -4 Pa), evaporate an Ag electrode with a thickness of 100 nm on the hole transport layer by thermal evaporation method to obtain a bismuth-based perovskite-type solar cell with a complete formal structure.

[0062] The test conditions are as follows: room temperature, atmospheric environment, the light condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW cm -2 . It can be known that the V OC of the battery obtained in Example 2 is 0.64 V, and the J SC is 2.34 mA cm -2 , and the PCE is 0.85%.

[0063] Comparing Example 2 with Comparative Example 1, it can be known that after adding hypophosphorous acid, the short-circuit current density of the battery increases significantly, thereby improving the photoelectric conversion efficiency of the battery.

[0064] Example 3

[0065] This example provides a bismuth-based perovskite-type solar cell. As Figure 1 shown, the structure from bottom to top includes: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite-type light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite-type light-absorbing layer.

[0066] The preparation method of this formal bismuth-based perovskite-type Cu 2 AgBiI 6 solar cell includes the following steps:

[0067] Step 1: The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then treated with ultraviolet ozone cleaning for 15 min to obtain a clean surface;

[0068] Take a SnO particle dispersion with a dispersion concentration of 5 wt%, coat it on the clean transparent conductive substrate, and anneal it to prepare an electron transport layer, which is transferred to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min; 2

[0069] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF with a volume ratio of DMSO to DMF of 3:1. The concentration of CuI added to the mixed solvent is 119.1 mg / mL, -1 the concentration of AgI is 120.9 mg / mL, -1 and the concentration of BiI 3 is 258.6 mg / mL; -1 After heating and stirring and then filtering, the temperature of heating and stirring is 100 °C and the time is 1 h. Hypophosphorous acid with a concentration of 0.50 vol% is added to the filtrate and reacted for 3 h to obtain a bismuth-based perovskite Cu 2 AgBiI 6 precursor solution;

[0070] Spin-coat the precursor solution on the electron transport layer at a speed of 3000 rpm for 60 s, with a spin coating thickness of 270 nm. First, pre-anneal at 50 °C for 50 min, and then anneal at 150 °C for 3 min to prepare a bismuth-based perovskite light-absorbing layer.

[0071] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene, mix well, and then drop it onto the bismuth-based perovskite light-absorbing layer and spin coat it at a speed of 3000 rpm for 30 s to prepare a hole transport layer;

[0072] Step 4: Under high vacuum (10 -4 Pa), evaporate a 100-nm-thick Ag electrode on the hole transport layer by thermal evaporation method, and then a bismuth-based perovskite solar cell with a complete formal structure is fabricated.

[0073] The test conditions are as follows: room temperature, atmospheric environment, the light illumination condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW / cm -2 . It can be known that the V OC of the battery obtained in Example 3 is 0.60 V, and the J SC is 2.01 mA / cm​-2 , the PCE is 0.78%.

[0074] Comparing Example 3 with Comparative Example 1, it can be seen that after adding hypophosphorous acid, the short-circuit current density of the battery increases significantly, thereby improving the photoelectric conversion efficiency of the battery.

[0075] Comparative Example 2

[0076] This comparative example provides a bismuth-based perovskite solar cell, as Figure 1 shown, which sequentially includes from bottom to top: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode.

[0077] The preparation method of this bismuth-based perovskite CuAgBiI 5 solar cell includes the following steps:

[0078] Step 1: The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then treated with ultraviolet ozone cleaning for 15 min to obtain a clean surface;

[0079] Take a SnO 2 particle dispersion with a dispersion concentration of 5 wt%, coat it on the clean transparent conductive substrate, and anneal it to prepare an electron transport layer, and transfer it to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min;

[0080] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF, the volume ratio of DMSO to DMF is 3:1, and the molar ratio of CuI, AgI, and BiI 3 added to the mixed solvent is 1:1:1 (concentration is 0.45 M); after heating and stirring, filter, the temperature of heating and stirring is 100 °C, the time is 1 h, and obtain the bismuth-based perovskite CuAgBiI 5 precursor solution;

[0081] Spin-coat the precursor solution on the electron transport layer, spin-coat at a speed of 3000 rpm for 60 s, the spin-coat thickness is 260 nm, pre-anneal at 50 °C for 50 min first, and then anneal at 150 °C for 3 min to prepare a bismuth-based perovskite light-absorbing layer.

[0082] Step 3: Dissolve 78.5 mg of hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene, mix well and then drop it onto the bismuth-based perovskite light-absorbing layer, and spin-coat at a speed of 3000 rpm for 30 s to prepare a hole transport layer;

[0083] Step 4. Under high vacuum (10 -4 Pa), an Ag electrode with a thickness of 100 nm is deposited on the hole transport layer by thermal evaporation method, thus obtaining a bismuth-based perovskite solar cell with a complete formal structure.

[0084] Figure 4 For the current density-voltage characteristic curve of the formal bismuth-based perovskite CuAgBiI 5 solar cell, the test conditions are as follows: room temperature, atmospheric environment, illumination condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW cm -2 . It can be seen that the V OC of the cell obtained in Comparative Example 2 is 0.62 V, and the J SC is 1.54 mA cm -2 , and the PCE is 0.51%.

[0085] Example 4

[0086] This example provides a bismuth-based perovskite solar cell. As Figure 1 shown, the structure sequentially includes from bottom to top: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite light-absorbing layer.

[0087] The preparation method of the formal bismuth-based perovskite CuAgBiI 5 solar cell includes the following steps:

[0088] Step 1. The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropanol for 20 min in sequence, dried with nitrogen, and then subjected to ultraviolet ozone cleaning treatment for 15 min to obtain a clean surface;

[0089] Take a SnO 2 particle dispersion with a dispersion concentration of 10 wt%, coat it on the clean transparent conductive substrate, and anneal it to obtain an electron transport layer, and transfer it to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 50 nm, the annealing temperature is 150 °C, and the time is 30 min;

[0090] Step 2. Dissolve the bismuth-based perovskite light-absorbing layer precursor materials (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF, the volume ratio of DMSO to DMF is 3:1, and CuI, AgI, and BiI 3The molar ratio is 1:1:1 (concentration is 0.45 M); after heating and stirring, filtration is carried out. The temperature for heating and stirring is 100 °C and the time is 1 h. Hypophosphorous acid with a concentration of 0.25 vol% is added to the filtrate, and the reaction is carried out for 3 h to obtain a bismuth-based perovskite-type CuAgBiI 5 precursor solution;

[0091] The precursor solution is spin-coated on the electron transport layer at a speed of 3000 rpm for 60 s, and the spin-coated thickness is 260 nm. It is first pre-annealed at 50 °C for 50 min and then annealed at 150 °C for 3 min to obtain a bismuth-based perovskite-type light-absorbing layer.

[0092] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene, mix well and then drop it onto the bismuth-based perovskite-type light-absorbing layer, and spin-coat it at a speed of 3000 rpm for 30 s to obtain a hole transport layer;

[0093] Step 4: Under high vacuum (10 -4 Pa), an Ag electrode with a thickness of 100 nm is evaporated on the hole transport layer by thermal evaporation method, and thus a bismuth-based perovskite-type solar cell with a complete formal structure is fabricated.

[0094] Figure 5 For the current density-voltage characteristic curve of the formal bismuth-based perovskite-type CuAgBiI 5 solar cell obtained in Example 2, the test conditions are as follows: room temperature, atmospheric environment, the light illumination condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW cm -2 . It can be seen that the V OC of the cell obtained in Example 2 is 0.69 V, and the J SC is 2.98 mA cm -2 , and the PCE is 1.02%.

[0095] Example 5

[0096] This example provides a bismuth-based perovskite-type solar cell, as Figure 1 shown, which sequentially includes from bottom to top: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite-type light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite-type light-absorbing layer.

[0097] The preparation method of the formal bismuth-based perovskite-type CuAgBiI 5 solar cell includes the following steps:

[0098] Step 1: The ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropyl alcohol in sequence for 20 min, dried with nitrogen, and then subjected to ultraviolet ozone cleaning treatment for 15 min to obtain a clean surface;

[0099] Take a SnO dispersion concentration of 12 wt% 2 particle dispersion liquid, coat it on a clean transparent conductive substrate, anneal it, prepare an electron transport layer, and transfer it to a glove box filled with nitrogen; the spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 10 nm, the annealing temperature is 150 °C, and the time is 30 min;

[0100] Step 2: Dissolve the bismuth-based perovskite light-absorbing layer precursor material (CuI, AgI, and BiI 3 ) in a mixed solvent of DMSO and DMF. The volume ratio of DMSO to DMF is 3:1. Add CuI, AgI, and BiI to the mixed solvent 3 in a molar ratio of 1:1:1 (concentration of 0.45 M); filter after heating and stirring. The temperature of heating and stirring is 100 °C and the time is 1 h. Add hypophosphorous acid with a concentration of 0.15 vol% to the filtrate and react for 3 h to obtain the bismuth-based perovskite CuAgBiI 5 precursor solution;

[0101] Spin-coat the precursor solution on the electron transport layer at a speed of 3000 rpm for 60 s. The spin coating thickness is 200 nm. First, pre-anneal at 50 °C for 50 min, and then anneal at 150 °C for 3 min to prepare the bismuth-based perovskite light-absorbing layer.

[0102] Step 3: Dissolve 78.5 mg of the hole transport layer material (Spiro-OMeTAD) in 1 mL of chlorobenzene, mix well, and then drop it onto the bismuth-based perovskite light-absorbing layer and spin-coat it at a speed of 3000 rpm for 30 s to prepare the hole transport layer;

[0103] Step 4: Under high vacuum (10 -4 Pa), evaporate a 100-nm-thick Ag electrode on the hole transport layer by thermal evaporation method to obtain the bismuth-based perovskite solar cell with a complete formal structure.

[0104] The test conditions are as follows: room temperature, atmospheric environment, the light illumination condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW cm -2 . It can be known that the V of the battery obtained in Example 5 OC is 0.66 V, and the J SC is 2.45 mA cm -2 , and the PCE is 0.89%.

[0105] Example 6

[0106] This example provides a bismuth-based perovskite solar cell, such as Figure 1As shown, it structurally includes, from bottom to top in sequence: a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light-absorbing layer, a hole transport layer, and a metal electrode. Hypophosphorous acid is added as an additive to the bismuth-based perovskite light-absorbing layer.

[0107] This formal bismuth-based perovskite CuAgBiI 5 The preparation method of the solar cell includes the following steps:

[0108] Step 1: ITO conductive glass is ultrasonically treated with detergent, ultrapure water, acetone, and isopropyl alcohol for 20 min in sequence, dried with nitrogen, and then treated with ultraviolet ozone cleaning for 15 min to obtain a clean surface.

[0109] Take a SnO particle dispersion with a dispersion concentration of 5 wt%. 2 It is coated on the clean transparent conductive substrate and annealed to prepare the electron transport layer, and then transferred to a glove box filled with nitrogen. The spin coating speed is 3000 rpm, the time is 45 s, the spin coating thickness is 100 nm, the annealing temperature is 150 °C, and the time is 30 min.

[0110] Step 2: The precursor material of the bismuth-based perovskite light-absorbing layer (CuI, AgI, and BiI 3 ) is dissolved in a mixed solvent of DMSO and DMF. The volume ratio of DMSO to DMF is 3:1. The molar ratio of CuI, AgI, and BiI added to the mixed solvent is 1:1:1 (concentration is 0.45 M); after heating and stirring, it is filtered. The temperature of heating and stirring is 100 °C and the time is 1 h. Hypophosphorous acid with a concentration of 0.50 vol% is added to the filtrate and reacts for 3 h to obtain the precursor solution of bismuth-based perovskite CuAgBiI 3 5 The precursor solution is spin-coated on the electron transport layer at a speed of 3000 rpm for 60 s, and the spin coating thickness is 300 nm. It is first pre-annealed at 50 °C for 50 min and then annealed at 150 °C for 3 min to prepare the bismuth-based perovskite light-absorbing layer.

[0111]

[0112] Step 3: 78.5 mg of the hole transport layer material (Spiro-OMeTAD) is dissolved in 1 mL of chlorobenzene, mixed well and then dropped onto the bismuth-based perovskite light-absorbing layer and spin-coated at a speed of 3000 rpm for 30 s to prepare the hole transport layer.

[0113] Step 4: Under high vacuum (10 -4 Pa), a 100-nm-thick Ag electrode is deposited on the hole transport layer by thermal evaporation method, and the formal-structured bismuth-based perovskite solar cell is thus prepared.

[0114] The test conditions are as follows: room temperature, atmospheric environment, light irradiation condition is AM 1.5G simulated sunlight, and the light irradiation intensity is 100 mW cm -2 . It can be seen that the V OC of the battery obtained in Example 2 is 0.69 V, and the J SC is 2.18 mA cm -2 , and the PCE is 0.75%.

[0115] Comparing Examples 1-6 with Comparative Examples 1-2, it can be seen that after adding hypophosphorous acid, the short-circuit current density of the battery increases significantly, thereby improving the photoelectric conversion efficiency of the battery. The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention.

[0116] Those skilled in the art should understand that the above are only several specific embodiments of the present invention, rather than all embodiments. It should be pointed out that many modifications and improvements can be made by those of ordinary skill in the art. All modifications or improvements that do not exceed the scope of the claims shall be regarded as within the protection scope of the present invention.

Claims

1. A bismuth-based perovskite solar cell, characterized in that: Hypophosphorous acid is added as an additive to the bismuth-based perovskite-type light-absorbing layer.

2. The bismuth-based perovskite solar cell according to claim 1, characterized in that: The bismuth-based perovskite solar cell structure includes, from bottom to top, a transparent conductive substrate, an electron transport layer, a bismuth-based perovskite light absorbing layer, a hole transport layer and a metal electrode.

3. The bismuth-based perovskite solar cell according to claim 1, characterized in that: The transparent conductive substrate is ITO or FTO; the electron transport layer is SnO2; the hole transport layer is Spiro-OMeTAD; the metal electrode is Ag, Au, Al or Cu; the bismuth-based perovskite-type light-absorbing layer is a bismuth-based double perovskite derivative, and the chemical formula of the components is Cu2AgBiI6 and CuAgBiI5.

4. A method for preparing a bismuth-based perovskite solar cell according to any one of claims 1 to 3, characterized in that: The steps include: Step 1: clean the transparent conductive substrate to obtain a clean surface; apply the SnO2 particle dispersion on the clean transparent conductive substrate, and anneal to obtain an electron transport layer; Step 2, dissolving a bismuth-based perovskite-type light-absorbing layer precursor material in a mixed solvent of DMSO and DMF, heating and stirring, and filtering, adding a hypophosphorous acid additive to the filtrate, and reacting to obtain a light-absorbing layer precursor solution; The light absorbing layer precursor solution is spin-coated on the electron transport layer, and annealed to obtain a bismuth-based perovskite light absorbing layer; Step 3, dissolving the hole transport layer material in chlorobenzene, mixing well, and then dropping the mixture onto the bismuth-based perovskite light-absorbing layer, and spin coating to obtain the hole transport layer; Step 4: Under high vacuum conditions, a metal electrode is evaporated on the hole transport layer to obtain a bismuth-based perovskite solar cell with a complete formal structure.

5. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: In step 1, the transparent conductive substrate is ultrasonically cleaned using detergent, ultrapure water, acetone and isopropanol in sequence, then blown dry with nitrogen, and treated with an ultraviolet ozone cleaner to obtain a clean surface.

6. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: In step 1, the concentration of the SnO2 particle dispersion is 5-12%, the spin coating speed is 3000-6000 rpm, the time is 30-45 s, the spin coating thickness is 10-100 nm, the annealing temperature is 100-150° C., and the time is 20-30 min.

7. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: In step 2, the bismuth-based perovskite light-absorbing layer material is a cuprous halide salt, a silver halide salt and a bismuth halide salt, and the volume ratio of DMSO to DMF is (2-4):1; the dissolved concentration of the bismuth-based perovskite light-absorbing layer precursor material in the mixed solvent is 0.3-0.5M.

8. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: The heating and stirring temperature in step 2 is 100-150° C. and the time is 0.5-1 h; the amount of the hypophosphorous acid additive added to the filtrate is 0.15-0.50 vol%; the spin coating speed of the light absorbing layer precursor solution on the electron transport layer is 3000-6000 rpm, the time is 45-60 s, and the spin coating thickness is 200-300 nm; pre-annealing at 40-50° C. for 40-50 min, and then annealing at 100-150° C. for 3-5 min to obtain a bismuth-based perovskite light absorbing layer.

9. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: In step 3, the hole transport layer material is dissolved in chlorobenzene at a concentration of 50 to 100 mg / mL, the spin coating speed is 3000 to 4000 rpm, the time is 30 to 45 s, and the spin coating thickness is 50 to 100 nm.

10. The method for preparing a bismuth-based perovskite solar cell according to claim 4, characterized in that: In step 4, the thickness of the metal electrode is 100-150 nm.

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