Antimony sulfide solar cell with self-healing polyurethane as interface layer and preparation method and application of antimony sulfide solar cell

Abstract

The invention relates to an antimony sulfide solar cell with self-healing polyurethane as an interface layer and a preparation method and application thereof, and the structure of the solar cell comprises a conductive glass FTO substrate, a functional layer on the substrate, and a counter electrode at the top of the functional layer. The functional layer sequentially comprises a CdS electron transport layer, a Sb2S3 light absorption layer, a self-healing polyurethane interface layer and a spiro-OMeTAD hole transport layer from bottom to top, self-healing polyurethane contains disulfide bonds, the counter electrode is a gold electrode or a silver electrode, and the thickness of the self-healing polyurethane interface layer is 1-10 nm. The prepared self-healing polyurethane has high flexibility and good self-repairing capacity, the synthesis route is simple, the cost is low, and the prepared antimony sulfide solar cell has excellent photoelectric conversion efficiency and stability.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a self-healing polyurethane as the interface layer antimony sulfide solar cell, its manufacturing method, and its application. Background Technology

[0002] Solar cells can be divided into three generations based on their materials. The first generation of solar cells mainly consists of traditional silicon-based cells: primarily monocrystalline and polycrystalline silicon solar cells. These cells have the most mature technology and high photoelectric conversion efficiency (PCE), reaching over 24%, and are currently the most widely used type of solar cell. However, the high cost of refining high-purity silicon makes them less competitive compared to conventional power sources, thus limiting the large-scale application of silicon cells. The second generation of solar cells mainly consists of thin-film solar cells: primarily including semiconductor thin-film solar cells made of cadmium telluride, gallium arsenide, and copper indium gallium selenide. Although their PCE is greater than 20%, the toxicity of elements such as cadmium and arsenic, and the scarcity of elements such as indium and gallium, also limit their large-scale commercial application.

[0003] The significant progress made in the first two generations of photovoltaic products has demonstrated the enormous application prospects of photovoltaic technology in the new energy field, and has promoted the active participation of countries around the world in the exploration and research of a new generation of solar cells that are efficient, stable, green, and low-cost. The third generation of solar cells mainly includes novel solar cells such as dye-sensitized, organic / polymer, perovskite solar cells, and antimony-based chalcogenide solar cells. Among them, antimony sulfide (Sb₂S₃) is a stable V-VI group direct bandgap semiconductor material, abundant in the Earth's crust, and safe and non-toxic. Sb₂S₃ exhibits excellent photoelectric properties, such as a suitable bandgap of 1.7 eV and an absorption coefficient of 1.8 × 10⁻⁶ at 450 nm. 5 cm -1 It covers most of the visible light spectrum and is therefore considered one of the most promising solar cell materials for application. However, its quasi-one-dimensional crystal structure leads to significant anisotropy, is greatly affected by crystal orientation, and the density of deep-level defects severely restricts device performance. These defects are important factors affecting the PCE of the cell.

[0004] In the research of perovskite solar cells, many studies have used polymer thin films to modify the surface of the functional layers of the device and passivated the dangling bonds, achieving satisfactory results. Summary of the Invention

[0005] The technical problem solved by this invention is: due to the quasi-one-dimensional (Q1D) structure of Sb2S3, intrinsic defects such as vacancy defects (V S ) and cation antisite defects (Sb SAntimony sulfide exhibits low formation energy and deep transition energy levels. Competition among these defects leads to severe electron-hole recombination, which restricts the improvement of photoelectric conversion efficiency of Sb2S3 solar cells and limits the application of antimony sulfide solar cells.

[0006] The inventors believe that introducing interface materials (such as polyurethane) with defect passivation capabilities between the light absorption layer and hole transport layer of a solar cell is one of the important means to improve the photovoltaic performance of solar cells. Therefore, for the field of antimony-based chalcogenide solar cells, this invention innovatively proposes to synthesize a novel room-temperature self-healing polyurethane containing disulfide bonds and apply it as an interface modification layer material in antimony sulfide solar cells. After preparing an Sb2S3 thin film by chemical bath deposition, a self-healing polyurethane ultrathin interface passivation layer is constructed using a spin-coating process. This polymer layer has a dual function: on the one hand, it achieves self-healing properties through disulfide (SS) dynamic bonds to repair mechanical stress damage to the film; on the other hand, it can fill grain boundary defects, passivate surface dangling bonds, and block carrier recombination channels. The antimony sulfide solar cell with self-healing polyurethane as the interface layer prepared by this invention has higher photovoltaic performance parameters (open circuit voltage (V)). oc ), short-circuit current density (J sc It has higher fill factor (FF) and photoelectric conversion efficiency (PCE), as well as stronger mechanical stability and longer service life.

[0007] Specifically, in view of the shortcomings of the existing technology, the present invention provides the following technical solution:

[0008] This invention provides a self-healing polyurethane as an interface layer for an antimony sulfide solar cell. The solar cell structure includes a conductive glass FTO substrate, a functional layer on the substrate, and a counter electrode on top of the functional layer. The functional layer, from bottom to top, consists of a CdS electron transport layer, an Sb2S3 light absorption layer, a self-healing polyurethane interface layer, and a spiro-OMeTAD hole transport layer. The self-healing polyurethane contains disulfide bonds, and the counter electrode is a gold or silver electrode.

[0009] The self-healing polyurethane is a self-healing polyurethane SSPU based on PTMEG-2000 soft segments.

[0010] Preferably, in the above-mentioned antimony sulfide solar cell, the thickness of the self-healing polyurethane interface layer is 1~10 nm.

[0011] Preferably, in the above-mentioned antimony sulfide solar cell, the thickness of the CdS electron transport layer is 50-70 nm. The thickness of the Sb₂S₃ light-absorbing layer is 300-350 nm. The thickness of the spiro-OMeTAD hole transport layer is 60-70 nm. The thickness of the counter electrode is 60-70 nm.

[0012] Preferably, in the above-mentioned antimony sulfide solar cell, the CdS electron transport layer, Sb2S3 light absorption layer, self-healing polyurethane interface layer and spiro-OMeTAD hole transport layer have the same area, and the area of ​​the counter electrode accounts for 3% to 5% of the area of ​​the CdS electron transport layer.

[0013] Preferably, in the above-mentioned antimony sulfide solar cell, the area of ​​the conductive glass FTO substrate is 3 cm². 2 In the aforementioned functional layers, the areas of the CdS electron transport layer, Sb₂S₃ light absorption layer, self-healing polyurethane interface layer, and spiro-OMeTAD hole transport layer are 2.50~2.55 cm². 2 The area of ​​the counter electrode is 0.09~0.10 cm². 2 .

[0014] The present invention also provides a method for preparing antimony sulfide solar cells with the above-mentioned self-healing polyurethane as the interface layer, characterized by comprising the following steps:

[0015] (1) Preparation of self-healing polyurethane material: Using polytetrahydrofuran, isophorone diisocyanate, dibutyltin dilaurate, 1,4-butanediol, bis(2-hydroxyethyl) disulfide, and N,N-dimethylacetamide as raw materials, self-healing polyurethane material was prepared.

[0016] (2) Preparation of antimony sulfide solar cells: After cleaning the conductive glass, CdS electron transport layer, Sb2S3 thin film, self-healing polyurethane interface layer, spiro-OMeTAD hole transport layer and gold or silver counter electrode are prepared on the conductive glass from bottom to top to form antimony sulfide solar cells.

[0017] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the self-healing polyurethane material includes the following steps:

[0018] (1) Add the dried polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate into a three-necked flask, add N,N-dimethylacetamide to dissolve it, place it in an oil bath, install a spherical condenser, connect the double row of tubes, repeat the vacuuming and nitrogen purging operations to maintain a nitrogen atmosphere and carry out the reaction.

[0019] (2) Add 1,4-butanediol and N,N-dimethylacetamide to the reaction system and continue the reaction to obtain the prepolymer;

[0020] (3) Add bis(2-hydroxyethyl) disulfide and N,N-dimethylacetamide to the prepolymer system and continue the reaction;

[0021] (4) Pour the liquid product obtained in step (3) into a flask, vacuum evaporate it, take the high viscosity liquid product into a separatory funnel, add ice hexane and shake it well. After standing and separating the layers, take the lower layer of liquid product into a polytetrafluoroethylene mold, vacuum dry it to remove the solvent, and after curing, obtain a transparent self-healing polyurethane material.

[0022] Preferably, in the above preparation method, in step (1), the addition ratio of polytetrahydrofuran, isophorone diisocyanate, dibutyltin dilaurate and N,N-dimethylacetamide is (2.2~2.7) g: (0.9~1.1) g: (1~2) mg: (4~5) mL; in step (2), the addition ratio of 1,4-butanediol and N,N-dimethylacetamide is (0.2~0.3) g: (4~5) mL; in step (3), the addition ratio of bis(2-hydroxyethyl) disulfide and N,N-dimethylacetamide is (0.1~0.2) g: (4~5) mL.

[0023] Preferably, in the above preparation method, the reaction temperature in steps (1), (2), and (3) is 80~90℃.

[0024] Preferably, in the above preparation method, in step (2), during the reaction process, it is necessary to constantly observe the speed of the stir bar in the three-necked flask and the viscosity of the solution. Once the speed of the stir bar slows down and the solution becomes viscous, the solvent DMAc should be added to the mixed system immediately.

[0025] Preferably, in the above preparation method, in step (4), the temperature of the rotary evaporator is 80~90 ℃ and the temperature of the vacuum drying oven is 80~90 ℃.

[0026] Preferably, in the above preparation method, the conductive glass FTO cleaning process includes the following steps:

[0027] The conductive glass was ultrasonically treated sequentially with detergent (main components: water, surfactant, chelating agent, pH adjuster), deionized water, acetone and isopropanol for 20-30 min, dried in an oven and then treated with a UV-ozone cleaner for 20-30 min.

[0028] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the electron transport layer CdS includes the following steps:

[0029] Mix 20-25 mL of Cd(NO3)2·4H2O solution with 20-30 mL of ammonia water, then add 12-14 mL of thiourea solution and 140-150 mL of deionized water. After thorough stirring, pour the mixture into a glass bottle containing clamped conductive glass and place it in a water bath at 70-75 °C to complete the deposition of a cadmium sulfide thin film. Dry the film on a hot plate at 100-150 °C. Spin-coat 70-100 μL of CdCl2 / methanol solution (3000-4000 rpm, 25-30 s) onto the surface of the cadmium sulfide thin film and anneal it on a hot plate at 400-450 °C to complete the preparation of the electron transport layer CdS, thus obtaining a CdS / FTO substrate.

[0030] The concentrations of the Cd(NO3)2·4H2O solution were 12–17 mmol / L, the concentrations of the thiourea solution were 0.5–1.0 mol / L, and the concentrations of the CdCl2 / methanol solution were 15–20 mg / mL.

[0031] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the Sb₂S₃ thin film includes the following steps:

[0032] Place the CdS / FTO substrate in a polytetrafluoroethylene container. Weigh 2.2–2.3 g of potassium antimony tartrate hemihydrate and 20–40 mg of disodium ethylenediaminetetraacetate and dissolve them in 120–140 mL of ultrapure water. Stir thoroughly until completely dissolved. Add 7–8 g of sodium thiosulfate and 0.3–0.4 g of thioacetamide and stir until a pale yellow color appears. Stop stirring immediately and pour the solution into a container. Add 70–100 μL of 1–2 mg / mL sodium dodecyl sulfate solution. Place the container in a 90–95 °C constant temperature bath and react for 200–280 min to complete the deposition of the Sb2S3 film. Transfer the solution to a glove box and anneal on a hot plate at 350–360 °C to obtain the Sb2S3 film on the CdS / FTO substrate.

[0033] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the self-healing polyurethane interface layer includes the following steps:

[0034] Prepare a 0.1–1.0 mg / mL self-healing polyurethane solution using ultra-dry chlorobenzene as the solvent. Filter and transfer the solution to a glove box. Spin-coat 70–100 μL of the solution onto an Sb2S3 film (3000–4000 rpm, 40–45 s). After spin-coating, heat and dry the film on a hot plate at 100–150 °C. Allow it to cool naturally to obtain an FTO / CdS / Sb2S3 / SSPU substrate.

[0035] Preferably, the concentration of the above-mentioned curable polyurethane solution is 0.3~0.5 mg / mL.

[0036] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the spiro-OMeTAD hole transport layer includes the following steps:

[0037] Inside the glove box, prepare the spiro-OMeTAD solution and add 70-100 μL to the FTO / CdS / Sb2S3 / SSPU substrate using a pipette. Spin coat at 3000-4000 rpm for 40-45 s. After spin coating, place it on a heating plate at 100 ℃ to dry. After it cools naturally, remove it from the glove box to obtain the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate.

[0038] Preferably, in the above-mentioned method for preparing antimony sulfide solar cells, the preparation process of the counter electrode includes the following steps:

[0039] Using a vacuum evaporation process, an FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate is inverted in an evaporation mold, a mask is added, and a metal counter electrode is formed by thermal evaporation, ultimately yielding a antimony sulfide solar cell with a self-healing polyurethane interface layer.

[0040] This invention also provides applications of the above-mentioned antimony sulfide solar cells with self-healing polyurethane as the interface layer in the photovoltaic, construction, aerospace and agricultural fields.

[0041] In this invention, disulfide-bonded polyurethane (SSPU) is used to form an ultrathin interface layer through a spin coating process. Its mechanism of action includes two aspects:

[0042] (1) Defect passivation function: The N, O and S in the self-healing polyurethane backbone contain lone pairs of electrons, which can act as passivation groups and interact with the positive charge at the interface (such as Sb). 3+ Defect coordination improves charge mobility and inhibits charge recombination; at the same time, polymer filling of thin film grain boundaries blocks the direct contact channel between electron transport layer (such as CdS) and hole transport layer (such as spiro-OMeTAD), reduces interface resistance, and inhibits charge recombination.

[0043] (2) Dynamic self-healing function: When the device is subjected to bending or mechanical stress, microcracks may be generated in the Sb2S3 film, leading to performance degradation. The dynamic SS bonds in the SSPU preferentially break and rebond in the stress concentration area, repairing the cracks and restoring the charge transport channel, thereby improving the mechanical stability and service life of the device.

[0044] The beneficial effects of this invention are as follows:

[0045] (1) The SSPU synthesized in this invention has an amorphous structure, which has high flexibility and good self-healing ability. It also has the advantages of simple synthesis route, readily available raw materials and low cost.

[0046] (2) The antimony sulfide solar cell with self-healing polyurethane as the interface layer prepared by the present invention has higher photoelectric conversion efficiency and stability compared with traditional antimony sulfide cells. Attached Figure Description

[0047] Figure 1 This is a synthesis route diagram of the self-healing polyurethane (SSPU) in the examples.

[0048] Figure 2 This is a structural diagram of the antimony sulfide solar cell with self-healing polyurethane as the interface layer obtained in Example 1.

[0049] Figure 3 The image shows the FT-IR spectrum of the SSPU obtained in Example 1.

[0050] Figure 4 The image shows the Raman spectrum of the SSPU obtained in Example 1.

[0051] Figure 5 The steady-state fluorescence spectra are those of the Sb2S3 film obtained in the comparative example (Control group) and the SSPU-modified Sb2S3 film obtained in Example 1 (SSPU-Modified).

[0052] Figure 6 The time-resolved fluorescence spectra of the Sb2S3 thin film obtained in the comparative example (Control group) and the SSPU-modified Sb2S3 thin film obtained in Example 1 (SSPU-Modified) are shown.

[0053] Figure 7 This is a comparison chart showing the photovoltaic characteristic parameters of antimony sulfide solar cells obtained in Examples 1 to 4.

[0054] Figure 8 This is a comparison chart of photovoltaic characteristic parameters for the Control group (no scratches), the Control group (scratched), the SSPU group (no scratches), and the SSPU group (scratched). Detailed Implementation

[0055] Given that the photoelectric performance of existing antimony sulfide solar cells still needs improvement, this invention provides an antimony sulfide solar cell with a self-healing polyurethane (SSPU) interface layer, its preparation method, and its applications. Antimony sulfide exhibits excellent photoelectric performance and is considered one of the most promising solar cell materials. However, when the device is subjected to bending or mechanical stress, the antimony sulfide film may develop microcracks, leading to performance degradation. This invention synthesizes a room-temperature self-healing polyurethane (SSPU) and spin-coates it onto an antimony sulfide light-absorbing layer to prepare an antimony sulfide solar cell with self-healing capabilities. This improves the photovoltaic performance of the device while also enhancing its mechanical stability and lifespan. The method of this invention is novel, simple to operate, and has significant application value and potential.

[0056] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments listed below are only for explaining the present invention and are not intended to limit the present invention. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] In a preferred embodiment, the solar cell device of the present invention has a structure of FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD / Ag, and the fabrication method is as follows:

[0058] Step 1: Using polytetrahydrofuran (PTMEG), isophorone diisocyanate (IPDI), dibutyltin dilaurate (DBTDL), 1,4-butanediol (BDO), bis(2-hydroxyethyl) disulfide (HEDS), and N,N-dimethylacetamide (DMAc) as raw materials, a self-healing polyurethane (SSPU) material is prepared.

[0059] Step 2: Prepare antimony sulfide solar cells with self-healing polyurethane as the interface layer.

[0060] Furthermore, the process for preparing self-healing polyurethane materials specifically includes the following steps:

[0061] Step 1.1: Add the dried PTMEG, IPDI, and DBTDL to a three-necked flask, add a certain amount of DMAc to dissolve, place the flask in an oil bath, install the spherical condenser, and connect the double-row tubes. Repeat the vacuuming and nitrogen purging process three times to maintain a nitrogen atmosphere, and react for 2-4 hours.

[0062] Step 1.2: Add BDO and DMAc to the reaction system and continue the reaction for 2-4 hours;

[0063] Step 1.3: Add HEDS and DMAc to the prepolymer system and react for 2-4 hours;

[0064] Step 1.4: Pour the liquid product into a flask and vacuum rotary evaporate for 10-25 min. Take the high-viscosity liquid product after rotary evaporation into a separatory funnel, add ice hexane and shake well. After standing and separating into layers, take the lower layer of liquid product and pour it into a PTFE mold. Place it in a vacuum drying oven and dry for 40-60 h to remove the solvent. After curing, a transparent SSPU is obtained.

[0065] In step 1.1 above, the amount of PTMEG added is 2.2~2.7 g, the amount of IPDI added is 0.9~1.1 g, the amount of DBTDL added is 1~2 mg, and the amount of DMAc added is 4~5 mL; in step 2.2, the amount of BDO added is 0.2~0.3 g, and the amount of DMAc added is 4~5 mL; in step 2.3, the amount of HEDS added is 0.1~0.2 g, and the amount of DMAc added is 4~5 mL; in step 2.4, the amount of ice-cold hexane added is 4~5 mL. Further, in step 1.1, the oil bath temperature range is 80~90 °C.

[0066] In step 1.2, the oil bath temperature range is 80~90 ℃. It is necessary to constantly observe the stirring speed and the viscosity of the solution in the three-necked flask. Once the stirring speed slows down or the solution becomes viscous, the solvent DMAc should be added to the mixture immediately.

[0067] In step 1.4, the temperature of the rotary evaporator is 80~90 ℃, and the temperature of the vacuum drying oven is 80~90 ℃.

[0068] Furthermore, the fabrication process of antimony sulfide solar cells with self-healing polyurethane as the interface layer specifically includes the following steps:

[0069] Step 2.1 Cleaning of conductive glass FTO: The FTO glass is ultrasonically treated with detergent, deionized water, acetone and isopropanol in sequence for 20-30 min, dried in an oven and then treated with a UV-ozone cleaner for 20-30 min.

[0070] Step 2.2, Preparation of the electron transport layer CdS: Mix 20-25 mL of Cd(NO3)2·4H2O solution with 20-30 mL of ammonia water and stir for 90 s. Add 12-14 mL of thiourea solution and 140-150 mL of deionized water. After thorough stirring, pour the mixture into a glass bottle containing clamped FTO conductive glass. Place the bottle in a water bath at 70-75 ℃ and react for 13-16 min to complete film deposition. Rinse the deposited film sequentially with ultrapure water and anhydrous ethanol, dry it with a hair dryer, wipe the bottom and back of the conductive area sequentially with hydrochloric acid and anhydrous ethanol, dry it with a rubber bulb, and heat it on a 100 ℃ hot plate for 10 min. Spin-coat 70-100 μL of CdCl2 / methanol solution (3000-4000 rpm, 30 s) onto the cadmium sulfide surface and anneal it on a 400 ℃ hot plate for 10-15 min.

[0071] Step 2.3, Preparation of Sb2S3 thin film: Place the CdS / FTO substrate in a polytetrafluoroethylene container, weigh out potassium antimony tartrate hemihydrate (APT) and disodium ethylenediaminetetraacetate (EDTA-2Na) and dissolve them in 120~140 mL of ultrapure water, stir thoroughly until completely dissolved, add sodium thiosulfate (STS) and thioacetamide (TAA), stir until a pale yellow color appears, immediately stop stirring, pour into a container, add 70~100 μL of sodium dodecyl sulfate (SDS) solution, place the container in a constant temperature bath at 90~95 ℃, react for 200~280 min, rinse the deposited film with ultrapure water and anhydrous ethanol in sequence, blow dry with a hair dryer, wipe the bottom of the conductive area with sodium hydroxide solution and anhydrous ethanol in sequence, blow dry with a rubber bulb, transfer to a glove box, and anneal on a hot plate at 350~360 ℃ for 15 min;

[0072] Step 2.4, Preparation of SSPU interface layer: Weigh a certain amount of SSPU, prepare a solution with ultra-dry chlorobenzene as solvent, filter through a 0.22 μm filter and transfer to a glove box, spin-coat 70~100 μL of the solution onto the Sb2S3 film (3000~4000 rpm, 40 s), and heat on a 100 ℃ heating plate for 5 min after spin-coating, and allow it to cool naturally;

[0073] Step 2.5, Preparation of the spiro-OMeTAD hole transport layer: In the glove box, prepare the spiro-OMeTAD solution and add 70~100 μL to the FTO / CdS / Sb2S3 / SSPU substrate using a pipette. Spin coat at 3000 rpm for 40 s. After spin coating, place it on a pre-set 100 ℃ heating plate and heat for 10 min. After it cools naturally, remove it from the glove box and wipe the bottom of the conductive area with acetonitrile and anhydrous ethanol in sequence, and blow dry with a rubber bulb.

[0074] Step 2.6, Preparation of silver electrode: Using vacuum evaporation process, the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate is placed upside down in the evaporation mold, and the metal counter electrode is formed by thermal evaporation. Finally, a antimony sulfide solar cell with self-healing polyurethane as the interface layer can be obtained.

[0075] The following specific embodiments further illustrate the antimony sulfide solar cell with self-healing polyurethane as the interface layer, its manufacturing method, and its application.

[0076] In the examples below, the information on the reagents and instruments used is shown in the table below. All other reagents were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0077] Table 1. Reagent and Instrument Information

[0078] Reagents / Instruments Specifications / Model Manufacturer / Source Spin Coator EZ4-S Jiangsu Leibo Scientific Instruments Co., Ltd. Fourier transform infrared spectrometer Nicolet iS50 Thermo Fisher Scientific, USA Microconfocal laser Raman spectrometer Xplora plus Horiba, France Steady-state / transient fluorescence spectrometer FLS1000 Edinburgh, UK Simulated solar light source Newport 94063A Newport Corporation, USA <![CDATA[Polytetrahydrofuran (M n ≈2000), PTMEG]]> AR Shanghai Aladdin Biochemical Technology Co., Ltd. 2-Hydroxyethyl disulfide, HEDS 90% Shanghai Aladdin Biochemical Technology Co., Ltd. Isophorone diisocyanate, IPDI 99% Shanghai McLean Biochemical Technology Co., Ltd. N,N-dimethylacetamide, DMAc AR, 99.0% Shanghai Aladdin Biochemical Technology Co., Ltd. 1,4-Butanediol, BDO 99% Shanghai Aladdin Biochemical Technology Co., Ltd. Dibutyltin dilaurate, DBTDL 95% Shanghai Aladdin Biochemical Technology Co., Ltd. Thiourea 99% Beijing Bailingwei Technology Co., Ltd. Cadmium nitrate tetrahydrate AR, 99% Sinopharm Chemical Reagent Co., Ltd. Potassium antimony tartrate hemihydrate, APT CP, ≥99% Sinopharm Chemical Reagent Co., Ltd. Sodium thiosulfate, pentahydrate, STS AR Shanghai Aladdin Biochemical Technology Co., Ltd. Thioacetamide, TAA ≥99.0% Shanghai Aladdin Biochemical Technology Co., Ltd. Disodium ethylenediaminetetraacetate (EDTA-2Na) 99% Shanghai McLean Biochemical Technology Co., Ltd. spiro-OMeTAD 99.8% Youxuan (Yingkou) Electronic Technology Co., Ltd.

[0079] Example 1

[0080] The steps for fabricating an antimony sulfide solar cell with a self-healing polyurethane interface layer are as follows:

[0081] 1.1 Preparation of self-healing polyurethane (SSPU): The synthetic route is as follows... Figure 1 As shown, PTMEG-2000 is polytetrahydrofuran, IPDI is isophorone diisocyanate, DBTDL is dibutyltin dilaurate, 1,4-butanediol (BDO), bis(2-hydroxyethyl) disulfide (HEDS), and N,N-dimethylacetamide (DMAc). The specific steps are as follows:

[0082] Dried PTMEG (2.4556 g), IPDI (1.0372 g), and DBTDL (0.0010 g) were added to a three-necked flask, and DMAc (4 mL) was added to dissolve them. A spherical condenser was installed, and the double-row tubes were connected. The vacuum and nitrogen purging process was repeated three times to maintain a nitrogen atmosphere, and the reaction was carried out at 80 °C for 3 hours. Then, BDO (0.2431 g) and DMAc (4 mL) were added to the reaction system. During this process, the stir bar speed and the viscosity of the solution in the three-necked flask needed to be constantly monitored. If the stir bar speed slowed down or the solution became viscous, DMAc was immediately added to the mixture, and the reaction continued for another 3 hours to synthesize the prepolymer. HEDS (0.1041 g) and DMAc (4 mL) were then added to the prepolymer system, and the reaction was continued for 3 hours. The final product was a liquid. All the above reactions were carried out at 80 °C under a N2 atmosphere. The liquid product was poured into a flask and vacuum-electrolyzed at 80 °C for 15 min. The high-viscosity liquid product after rotary evaporation was then placed in a separatory funnel, and 4 mL of ice-cold hexane (hexane at -10 to -18 °C) was added. The mixture was shaken and allowed to stand until it separated into layers. The lower layer of liquid product was then poured into a PTFE mold and placed in a vacuum oven at 80 °C for 48 h to remove the solvent. After curing, a transparent, curable polyurethane (SSPU) was obtained.

[0083] 1.2 Preparation of antimony sulfide solar cells, the steps are as follows:

[0084] Step (1), cleaning of conductive glass FTO: FTO glass with an area of ​​1.5 cm × 2.0 cm was ultrasonically treated with detergent, deionized water, acetone and isopropanol for 20 min in sequence, dried in an oven and then treated with a UV-ozone cleaner for 20 min.

[0085] Step (2), Preparation of the electron transport layer CdS: 20 mL of 15 mmol / L Cd(NO3)2·4H2O solution was mixed with 26 mL of ammonia and stirred for 90 s. 12.8 mL of 0.8 mol / L thiourea solution and 140 mL of deionized water were added. After thorough stirring, the mixture was poured into a glass bottle containing clamped FTO conductive glass and placed in a water bath at 70 ℃ for 15 min to complete the film deposition. The deposited film was rinsed sequentially with ultrapure water and anhydrous ethanol, dried with a hair dryer, and the bottom and back of the conductive area were wiped sequentially with hydrochloric acid and anhydrous ethanol, and dried with a syringe. The film was heated on a 100 ℃ hot plate for 10 min. 100 μL of 20 mg / mL CdCl2 / methanol solution was spin-coated onto the cadmium sulfide surface (3000 rpm, 30 s), and annealed on a 400 ℃ hot plate for 10 min. A CdS / FTO substrate was obtained, and the area of ​​the cadmium sulfide film was 1.5 cm × 1.7 cm. The thickness of the cadmium sulfide film was found to be 60 nm using scanning electron microscopy.

[0086] Step (3), Preparation of Sb2S3 thin film: The CdS / FTO substrate was placed in a polytetrafluoroethylene container. 2.2540 g APT and 0.03 g EDTA-2Na were weighed and dissolved in 140 mL of ultrapure water. The solution was stirred thoroughly until completely dissolved. 7.8180 g STS and 0.3381 g TAA were added and stirred until a pale yellow color appeared. Stirring was stopped immediately and the solution was poured into a container. 100 μL of SDS solution was added dropwise. The container was placed in a 95 ℃ constant temperature bath and reacted for 240 min. After cooling, the solution was rinsed with ultrapure water and anhydrous ethanol in sequence, dried with a hair dryer, and the bottom of the conductive area was wiped with sodium hydroxide solution and anhydrous ethanol in sequence. The solution was dried with a rubber bulb and transferred to a glove box filled with nitrogen atmosphere. The solution was annealed on a 360 ℃ hot plate for 15 min. An Sb2S3 thin film with a thickness of 300 nm was obtained on the CdS / FTO substrate.

[0087] Step (4), Preparation of the SSPU interface layer: Prepare a 0.5 mg / mL SSPU solution using ultra-dry chlorobenzene as the solvent. After complete dissolution, filter through a 0.22 μm filter and transfer to a glove box. In the glove box, spin-coat 100 μL of the solution onto the Sb2S3 film (3000 rpm, 40 s). After spin-coating, heat on a 100 ℃ hot plate for 5 min, and allow it to cool naturally to obtain the FTO / CdS / Sb2S3 / SSPU substrate. The thickness of the SSPU interface layer was measured to be 10 nm.

[0088] Step (5), preparation of the spiro-OMeTAD hole transport layer: In the glove box, prepare the spiro-OMeTAD solution and add 70 μL to the FTO / CdS / Sb2S3 / SSPU substrate using a pipette. Spin coat at 3000 rpm for 40 s. After spin coating, place it on a pre-set 100 ℃ heating plate and heat for 10 min. After it cools naturally, remove it from the glove box and wipe the bottom of the conductive area with acetonitrile and anhydrous ethanol in sequence. Dry it with a rubber bulb to obtain the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate. The thickness of the spiro-OMeTAD hole transport layer is 65 nm.

[0089] Step (6), Preparation of the silver electrode: Using a vacuum evaporation process, the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate was inverted in an evaporation mold containing a perforated template. After thermal evaporation, a metal counter electrode, i.e., the silver electrode, was formed on top of the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate. The silver electrode had an area of ​​0.3 cm × 0.3 cm and a thickness of 65 nm.

[0090] Using the above method, a antimony sulfide solar cell with a self-healing polyurethane interface layer was assembled. The structural diagram is shown below. Figure 2 As shown, the bottom layer is FTO conductive glass, and above the conductive glass is the functional layer. From bottom to top, the functional layer consists of a CdS electron transport layer, an Sb2S3 light absorption layer, a self-healing polyurethane (SSPU) interface layer, and a spiro-OMeTAD hole transport layer. The top of the functional layer is the counter electrode, i.e., the silver electrode.

[0091] Example 2

[0092] The steps for fabricating an antimony sulfide solar cell with a self-healing polyurethane interface layer are as follows:

[0093] 1.1 Self-healing polyurethane (SSPU) was prepared using the same method as in Example 1.

[0094] 1.2 Preparation of Antimony Sulfide Solar Cells

[0095] Steps (1), (2), and (3) are the same as in Example 1.

[0096] Step (4) Prepare a 0.1 mg / mL SSPU solution using ultra-dry chlorobenzene as the solvent. After complete dissolution, filter through a 0.22 μm filter and transfer to a glove box. In the glove box, spin-coat 100 μL of the solution onto a Sb2S3 film (3000 rpm, 40 s). After spin-coating, heat on a 100 ℃ hot plate for 5 min, and allow it to cool naturally to obtain the FTO / CdS / Sb2S3 / SSPU substrate.

[0097] Step (5), preparation of the spiro-OMeTAD hole transport layer: In the glove box, prepare the spiro-OMeTAD solution and add 70 μL to the FTO / CdS / Sb2S3 / SSPU substrate with a pipette. Spin coat at 3000 rpm for 40 s. After spin coating, place it on a pre-set 100 ℃ heating plate and heat for 10 min. After it cools naturally, remove it from the glove box and wipe the bottom of the conductive area with acetonitrile and anhydrous ethanol in sequence. Blow dry with a rubber bulb to obtain the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate.

[0098] Step (6), Preparation of silver electrode: Using vacuum evaporation process, the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate is placed upside down in the evaporation mold containing a hollow template. After thermal evaporation, a metal counter electrode, namely the silver electrode, is formed on the conductive area on the top of the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate.

[0099] Example 3

[0100] Example 3 is similar to Example 1, except that: in step (4) 1.2, the concentration of SSPU solution is 0.3 mg / mL.

[0101] Example 4

[0102] Example 4 is similar to Example 1, except that: in step (4) 1.2, the concentration of SSPU solution is 0.7 mg / mL.

[0103] Comparative Example

[0104] Similar to Example 1, the difference is that the preparation process of the self-healing polyurethane (SSPU) in 1.1 and the preparation process of the SSPU interface layer in step (4) of 1.2 are omitted. Antimony sulfide solar cells without SSPU modification were prepared as a control group or a trace-free control group.

[0105] The following performance tests were performed on the samples obtained from the examples and comparative examples:

[0106] (1) The FT-IR spectrum of the self-healing polyurethane SSPU prepared in Example 1 was detected by Fourier transform infrared spectroscopy, and the results are as follows: Figure 3 As shown in the figure. 3322 cm can be observed in the figure. -1 1698 cm -1 And 1234 cm -1 The characteristic absorption peaks at 2242 cm⁻¹ correspond to the stretching vibrations of NH, C=O, and CO in the urethane structure, respectively. The presence of these absorption peaks indicates that the urethane groups in the SSPU molecule have successfully formed a polymer chain. -1 The absence of a stretching vibration peak of -NCO indicates that the isocyanate groups in the raw materials have completely reacted, all of which prove the successful synthesis of polyurethane.

[0107] (2) The Raman spectrum of the self-healing polyurethane SSPU prepared in Example 1 was detected by a microconfocal laser Raman spectrometer. The results are as follows: Figure 4 As shown, the Raman spectrum reveals two important characteristic peaks in SSPU, appearing at 515 cm⁻¹. -1 and 641 cm -1 The two peaks correspond to the vibrations of disulfide bonds (SS) and sulfur-carbon bonds (CS), respectively, indicating that disulfide bonds (SS) were successfully introduced during polymer synthesis. The introduction of disulfide bonds is a key factor in SSPU's self-healing ability, providing a basis for dynamic rearrangement and enabling polyurethane to self-repair when subjected to cracks and damage.

[0108] (3) The steady-state fluorescence spectra of the unmodified Sb2S3 film obtained from the control group of Comparative Example 1 and the SSPU-modified Sb2S3 film obtained in step (4) of Example 1 were detected using a steady-state / transient fluorescence spectrometer. The results are as follows: Figure 5 As shown in the figure, the SSPU-modified Sb2S3 film exhibits a low steady-state fluorescence intensity at 764 nm, indicating that the SSPU interface layer can effectively passivate interface defects, reduce nonradiative recombination of charge carriers, and promote the transport of charge carriers in the film.

[0109] (4) Figure 6 The time-resolved fluorescence spectra of the control group (without SSPU modification) and the SSPU-modified Sb2S3 film obtained in step 1.2 (4) of Example 1 are compared. The τ of the SSPU-modified Sb2S3 film... ave The wavelength was 5.02 ns, shorter than that of the control Sb2S3 film (19.91 ns), indicating faster electron transfer in the modified film. This improvement is attributed to the reduction of interface defects, which mitigates nonradiative recombination.

[0110] (5) Figure 7 This is a comparison graph showing the photovoltaic characteristic parameters of antimony sulfide solar cells obtained from the control group and the groups modified with different concentrations of SSPU in Examples 1-4. The horizontal axis represents the concentration of the SSPU solution, with 0.1 for Example 2, 0.3 for Example 3, 0.5 for Example 1, and 0.7 for Example 4. The detection process was as follows: the current-voltage (JV) curves of the device were measured under AM 1.5 G illumination using a simulated solar light source (Newport 94063A) and a digital source meter (Keithley 2450). The open-circuit voltage (V) of the device was calculated based on the data. oc ), short-circuit current density (J sc The parameters, such as fill factor (FF) and power conversion efficiency (PCE), are shown in Tables 2-5, respectively. As can be seen from the tables, the photovoltaic performance parameters (VF) of the antimony sulfide solar cell with the SSPU-modified interface obtained in Example 1 are as follows: oc J sc All three parameters (FF and PCE) have been improved.

[0111] Table 2 Open Circuit Voltage (V) oc Comparison Table (V)

[0112] Comparative Example Example 1 Example 2 Example 3 Example 4 0.66 0.68 0.72 0.7 0.7 0.67 0.68 0.71 0.7 0.69 0.67 0.68 0.73 0.73 0.69 0.7 0.72 0.67 0.71 0.69 0.69 0.72 0.71 0.71 0.68 0.7 0.71 0.71 0.69 0.71 0.62 0.68 0.71 0.69 0.7 0.73 0.68 0.72 0.69 0.71 0.73 0.74 0.72 0.71 0.72 0.65 0.73 0.68 0.75 0.71

[0113] Table 3 Short-circuit current density (J) sc Comparison table (mA / cm) 2 )

[0114] Comparative Example Example 1 Example 2 Example 3 Example 4 15.05 15.30 15.17 15.05 15.6 15.00 15.46 15.36 15.14 15.87 15.16 15.44 16.08 16.17 14.76 16.386 15.84 16.10 16.49 14.93 16.49 15.81 14.95 16.50 15.03 16.40 15.87 14.86 14.99 15.18 15.45 15.51 14.94 14.84 15.32 14.64 15.47 16.04 14.97 15.39 14.73 16.05 16.12 16.30 16.29 14.73 16.18 14.40 15.16 16.33

[0115] Table 4 Comparison of Fill Factor (FF) (%)

[0116] Comparative Example Example 1 Example 2 Example 3 Example 4 0.46 0.52 0.51 0.49 0.51 0.48 0.53 0.52 0.48 0.52 0.48 0.54 0.52 0.53 0.51 0.51 0.53 0.51 0.54 0.51 0.52 0.53 0.54 0.55 0.51 0.52 0.53 0.54 0.54 0.51 0.49 0.51 0.55 0.54 0.52 0.55 0.50 0.52 0.55 0.51 0.55 0.55 0.52 0.55 0.54 0.48 0.55 0.51 0.55 0.55

[0117] Table 5 Comparison of Photoelectric Conversion Efficiency (PCE) (%)

[0118] Comparative Example Example 1 Example 2 Example 3 Example 4 4.60 5.46 5.61 5.12 5.53 4.86 5.53 5.77 5.05 5.67 4.88 5.63 6.057 6.31 5.21 5.90 6.03 5.55 6.35 5.23 5.96 5.99 5.73 6.43 5.21 6.02 5.95 5.74 5.60 5.45 4.66 5.41 5.79 5.57 5.56 5.87 5.27 5.99 5.64 5.59 5.95 6.53 6.05 6.34 6.38 4.57 6.47 4.95 6.21 6.32

[0119] To verify the self-healing efficacy of antimony sulfide solar cells with self-healing polyurethane as the interface layer, the antimony sulfide solar cells obtained in Example 1 were labeled as the SSPU scratch-free group, and the antimony sulfide solar cells obtained in the comparative example were labeled as the Control scratch-free group. The following methods were used to prepare the SSPU scratched group and the Control scratched group:

[0120] Using the same method as in Example 1, after step (4) in 1.2, an FTO / CdS / Sb2S3 / SSPU substrate was obtained. Lines were drawn on the SSPU film with a knife, and antimony sulfide solar cells were prepared using the methods in steps (5) and (6) of Example 1. The cells were labeled as the SSPU scratched group.

[0121] Using the same method as Comparative Example 1, after step (3) in 1.2, an Sb2S3 thin film was prepared on a CdS / FTO substrate. Lines were drawn on the Sb2S3 thin film with a knife. Using the same method as Comparative Example 1, a spiro-OMeTAD hole transport layer and a silver electrode were prepared to obtain an antimony sulfide solar cell, which was marked as the Control group with scratches.

[0122] Figure 8 This chart compares the photovoltaic (PV) performance parameters of the Control group (no scratches), the Control group (scratched), the SSPU group (no scratches), and the SSPU group (scratched). Specifically, compared to the Control group (no scratches), the PV performance parameters (Vg) of the Control group (scratched) are shown. oc J sc The photovoltaic characteristics of antimony sulfide solar cells with self-healing polyurethane as the interface layer are significantly reduced, while the photovoltaic characteristic parameters of the SSPU with scratches are only slightly reduced compared to the unscratched SSPU group. This indicates that the antimony sulfide solar cells with self-healing polyurethane as the interface layer have a certain self-healing effect, stronger mechanical stability, and longer service life.

[0123] In summary, the self-healing polyurethane prepared by this invention has high flexibility and good self-healing ability. Moreover, the synthesis route is simple, the raw materials are readily available, and the cost is low. The antimony sulfide solar cell with the self-healing polyurethane as the interface layer prepared by this invention has higher photovoltaic performance parameters, stronger mechanical stability, and longer service life, exhibiting excellent performance.

Claims

1. A self-healing polyurethane-based antimony sulfide solar cell, characterized in that, The structure of the solar cell includes a conductive glass FTO substrate, a functional layer on the substrate, and a counter electrode on top of the functional layer. The functional layer consists of a CdS electron transport layer, an Sb2S3 light absorption layer, a self-healing polyurethane interface layer, and a spiro-OMeTAD hole transport layer from bottom to top. The self-healing polyurethane contains disulfide bonds. The counter electrode is a gold electrode or a silver electrode.

2. The antimony sulfide solar cell according to claim 1, wherein, The thickness of the self-healing polyurethane interface layer is 1~10nm.

3. The method for preparing the antimony sulfide solar cell with self-healing polyurethane as the interface layer as described in claim 1, characterized in that, Includes the following steps: (1) Preparation of self-healing polyurethane material: Using polytetrahydrofuran, isophorone diisocyanate, dibutyltin dilaurate, 1,4-butanediol, bis(2-hydroxyethyl) disulfide, and N,N-dimethylacetamide as raw materials, self-healing polyurethane material was prepared. (2) Preparation of antimony sulfide solar cells: After cleaning the conductive glass, CdS electron transport layer, Sb2S3 thin film, self-healing polyurethane interface layer, spiro-OMeTAD hole transport layer and counter electrode are prepared on the conductive glass from bottom to top to form antimony sulfide solar cells.

4. The method for preparing an antimony sulfide solar cell according to claim 3, wherein, The preparation process of the self-healing polyurethane material includes the following steps: (1) Add the dried polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate into a three-necked flask, add N,N-dimethylacetamide to dissolve it, place it in an oil bath, install a spherical condenser, connect the double row of tubes, repeat the vacuuming and nitrogen purging operations to maintain a nitrogen atmosphere and carry out the reaction. (2) Add 1,4-butanediol and N,N-dimethylacetamide to the reaction system and continue the reaction to obtain the prepolymer; (3) Add bis(2-hydroxyethyl) disulfide and N,N-dimethylacetamide to the prepolymer system and continue the reaction; (4) Pour the liquid product obtained in step (3) into a flask, vacuum evaporate it, take the high viscosity liquid product into a separatory funnel, add ice hexane and shake it well. After standing and separating the layers, take the lower layer of liquid product into a polytetrafluoroethylene mold, vacuum dry it to remove the solvent, and after curing, obtain a transparent self-healing polyurethane material.

5. The preparation method according to claim 4, wherein, In step (1), the addition ratio of polytetrahydrofuran, isophorone diisocyanate, dibutyltin dilaurate and N,N-dimethylacetamide is (2.2~2.7) g: (0.9~1.1) g: (1~2) mg: (4~5) mL; in step (2), the addition ratio of 1,4-butanediol and N,N-dimethylacetamide is (0.2~0.3) g: (4~5) mL; in step (3), the addition ratio of bis(2-hydroxyethyl) disulfide and N,N-dimethylacetamide is (0.1~0.2) g: (4~5) mL.

6. The preparation method according to claim 5, wherein, The preparation process of the electron transport layer CdS includes the following steps: Mix 20-25 mL of Cd(NO3)2·4H2O solution with 20-30 mL of ammonia water, then add 12-14 mL of thiourea solution and 140-150 mL of deionized water. After thorough stirring, pour the mixture into a glass bottle containing clamped conductive glass and place it in a water bath at 70-75 °C to complete the deposition of a cadmium sulfide thin film. Dry the film on a hot plate at 100-150 °C. Spin-coat 70-100 μL of CdCl2 / methanol solution (3000-4000 rpm, 25-30 s) onto the surface of the cadmium sulfide thin film and anneal it on a hot plate at 400-450 °C to complete the preparation of the electron transport layer CdS, thus obtaining a CdS / FTO substrate. The concentrations of the Cd(NO3)2·4H2O solution were 12–17 mmol / L, the concentrations of the thiourea solution were 0.5–1.0 mol / L, and the concentrations of the CdCl2 / methanol solution were 15–20 mg / mL.

7. The preparation method according to claim 6, wherein, The preparation process of the Sb2S3 thin film includes the following steps: The CdS / FTO substrate was placed in a polytetrafluoroethylene container. 2.2–2.3 g of potassium antimony tartrate hemihydrate and 20–40 mg of disodium ethylenediaminetetraacetate were weighed and dissolved in 120–140 mL of ultrapure water. The solution was stirred thoroughly until completely dissolved. 7–8 g of sodium thiosulfate and 0.3–0.4 g of thioacetamide were added and stirred until a pale yellow color appeared. Stirring was stopped immediately and the solution was poured into a container. 70–100 μL of a 1–2 mg / mL sodium dodecyl sulfate solution was added dropwise. The container was placed in a constant temperature bath at 90–95 °C and reacted for 200–280 min to complete the deposition of the Sb₂S₃ thin film. The film was then transferred to a glove box and annealed on a hot plate at 350–360 °C to prepare the Sb₂S₃ thin film on the CdS / FTO substrate.

8. The preparation method according to claim 7, wherein, The preparation process of the self-healing polyurethane interface layer includes the following steps: Prepare a 0.1–1.0 mg / mL self-healing polyurethane solution using ultra-dry chlorobenzene as the solvent. Filter and transfer the solution to a glove box. Spin-coat 70–100 μL of the solution onto an Sb2S3 film (3000–4000 rpm, 40–45 s). After spin-coating, heat and dry the film on a hot plate at 100–150 °C. Allow it to cool naturally to obtain the FTO / CdS / Sb2S3 / SSPU substrate.

9. The preparation method according to claim 8, wherein, The fabrication process of the spiro-OMeTAD hole transport layer includes the following steps: Inside the glove box, prepare the spiro-OMeTAD solution and add 70-100 μL to the FTO / CdS / Sb2S3 / SSPU substrate using a pipette. Spin coat at 3000-4000 rpm for 40-45 s. After spin coating, place it on a heating plate at 100 ℃ to dry. After it cools naturally, remove it from the glove box to obtain the FTO / CdS / Sb2S3 / SSPU / spiro-OMeTAD substrate.

10. The application of the antimony sulfide solar cell with self-healing polyurethane as the interface layer as described in claim 1 in the photovoltaic, construction, aerospace, or agricultural fields.

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