Preparation method of high-efficiency wide-bandgap perovskite indoor photovoltaic device

Abstract

The application relates to the technical field of photovoltaic devices, in particular to a preparation method of a high-efficiency wide-bandgap perovskite indoor photovoltaic device, which comprises the following steps: preparing a hole transport layer; preparing a wide-bandgap perovskite thin film; doping treatment is conducted on a wide-bandgap perovskite precursor solution to form a perovskite precursor a solution, the perovskite precursor a solution is spin-coated on the hole transport layer of S1 to form the wide-bandgap perovskite thin film, and annealing treatment is conducted on the wide-bandgap perovskite thin film; conducting passivation treatment; a surface passivation additive is dissolved to prepare a b solution, the b solution is spin-coated on the wide-bandgap perovskite thin film of S2, and annealing treatment is conducted; preparing an electron transport layer; preparing a hole blocking layer; and preparing a metal electrode. The preparation method of the high-efficiency wide-bandgap perovskite indoor photovoltaic device is adopted, and the problems of phase separation and surface defects in the wide-bandgap perovskite material used for indoor photovoltaic in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic device technology, and in particular to a method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device. Background Technology

[0002] With the rapid development of information technology, an increasing number of IoT sensors are being deployed indoors, posing a significant challenge to traditional power supply methods. To reduce the power consumption of IoT devices, the industry has developed various low-power wireless communication protocols, such as Bluetooth Low Energy (BLE) and Zigbee. IoT devices based on these protocols typically consume power in the hundreds of microwatts. Under typical living and office conditions, indoor light intensity ranges from 200 to 2000 lux, corresponding to a power density of 50-1000 microwatts per square centimeter. A solar cell with an area of ​​several square centimeters and an efficiency of approximately 30% can output close to milliwatts of power under indoor lighting conditions, sufficient to meet the power supply needs of indoor IoT devices. Therefore, using indoor photovoltaic devices to power IoT devices is an effective solution that addresses both the challenges of distributed power supply requirements and maintenance costs.

[0003] Perovskite solar cells have attracted widespread research attention due to their superior photoelectric performance, tunable bandgap, simple manufacturing process, and low cost. However, because indoor light sources differ significantly from sunlight, traditional high-efficiency perovskite solar cell devices under sunlight are not the optimal choice for indoor photovoltaic devices. To meet the highest efficiency requirements of indoor photovoltaic devices, wide-bandgap perovskite materials are needed.

[0004] Current strategies for achieving wide-bandgap perovskite materials primarily involve replacing some iodide ions with bromide ions in the perovskite composition. However, under illumination, iodide and bromide ions in wide-bandgap perovskites aggregate and undergo phase separation. This phase separation leads to the formation of bromide-enriched and iodine-enriched regions, which become major carrier traps, severely reducing the efficiency and phase stability of indoor photovoltaics. Furthermore, surface defects in the perovskite also cause severe non-radiative recombination of carriers, further reducing the efficiency of wide-bandgap perovskite solar cells under indoor conditions. Therefore, it is crucial to improve the phase stability of wide-bandgap perovskite materials and reduce the impact of surface defects on cell performance, thereby enhancing the efficiency of wide-bandgap perovskite indoor photovoltaics. Summary of the Invention

[0005] The purpose of this invention is to provide a method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device, which solves the problems of phase separation and surface defects in wide-bandgap perovskite materials used for indoor photovoltaics in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for fabricating a high-efficiency, wide-bandgap perovskite indoor photovoltaic device, comprising the following steps:

[0007] S1 Preparation of hole transport layer: After cleaning and drying the transparent conductive ITO substrate, it is treated with ultraviolet ozone or plasma. Hole transport material is spin-coated on the surface of the treated ITO substrate and then annealed to form a hole transport layer for later use.

[0008] S2 Preparation of wide-bandgap perovskite thin film: Prepare wide-bandgap perovskite precursor solution, dope the wide-bandgap perovskite precursor solution to form perovskite precursor a solution, spin-coat the perovskite precursor a solution onto the hole transport layer of S1 to form wide-bandgap perovskite thin film, and anneal the wide-bandgap perovskite thin film.

[0009] S3 undergoes surface passivation treatment: the surface passivation additive is dissolved to prepare solution b, solution b is spin-coated onto the wide-bandgap perovskite film of S2, and then annealed.

[0010] S4 preparation of electron transport layer: deposit an electron transport layer on the wide-bandgap perovskite film after S3 treatment;

[0011] S5 Preparation of Hole Blocking Layer: Hole blocking layer material is deposited on the electron transport layer prepared in S4;

[0012] S6 Preparation of Metal Electrode: Deposit a metal electrode on the hole blocking layer prepared in S5.

[0013] Preferably, the hole transport material in S1 is PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]). The PTAA solution is spin-coated onto the ITO substrate and annealed at 100°C for 10 minutes. Then, a methanol solution of PFN-Br is spin-coated onto the PTAA surface to form a PTAA / PFN-Br hole transport layer. The hole transport layer is annealed at 100°C for 10 seconds, and then step S2 is performed immediately.

[0014] Preferably, in step S2, a wide-bandgap perovskite precursor solution is prepared by mixing and dissolving FAI (formaldehyde iodide), CsI (cesium iodide), PbI2 (lead iodide), and PbBr2 (lead bromide) in a mixed solution of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide), wherein the molar ratio of FAI, CsI, PbI2, and PbBr2 is 0.8:0.2:0.4:0.6.

[0015] Preferably, the doping treatment in S2 is performed using HAI (hexylamine hydroiodide) or HABr (hexylamine hydrobromide). The doping treatment involves adding HAI and Pb(SCN)2 (lead thiocyanate) or HABr and Pb(SCN)2 to the wide-bandgap perovskite precursor solution for doping treatment.

[0016] Preferably, the surface passivation additive in S3 is ThEAI (thiophene ethyl iodide ammonium) or ThEABr (thiophene ethyl bromide ammonium); when the perovskite precursor solution a is doped with HAI, solution b is made by dissolving ThEAI in IPA (isopropanol) and stirring until homogeneous; when the perovskite precursor solution a is doped with HABr, solution b is made by dissolving ThEABr in IPA and stirring until homogeneous.

[0017] The precursor additive HAI in S2 and the surface passivation additive ThEAI in S3 must be used together; or the precursor additive HABr in S2 and the surface passivation additive ThEABr in S3 must be used together, thereby improving the efficiency of wide-bandgap perovskite indoor photovoltaic devices.

[0018] Preferably, the electron transport material in S4 is fullerene C60.

[0019] Preferably, the hole-blocking material in S5 is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0020] Preferably, the metal electrode material in S6 is a silver electrode, and the electrode thickness is 80-150 nm.

[0021] A method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device.

[0022] The beneficial effects of this invention are:

[0023] (1) In this invention, wide-bandgap perovskite material is selected as the light absorption layer of indoor photovoltaic device to meet the requirement of ideal bandgap width of indoor photovoltaic device. Two iodide salts or bromide salts, HAI and ThEAI or HABr and ThEABr, are used for bulk phase and surface doping, respectively, to improve the phase stability of wide-bandgap perovskite material and reduce the influence of surface defects on the photoelectric properties of perovskite.

[0024] (2) The wide-bandgap perovskite indoor photovoltaic device prepared by the present invention can achieve an energy conversion efficiency of 38.18% under white LED illumination at 3800K and 1200 lux, which meets the power supply requirements of commercial IoT sensors, promotes the development of wide-bandgap perovskite indoor photovoltaic devices, and promotes the application of perovskite technology in IoT devices.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1This is a curve showing the variation of the theoretical maximum efficiency of solar cells with the bandgap width of the absorber layer material under different illumination conditions;

[0027] Figure 2 This is a graph showing the in-situ fluorescence spectroscopy test results of the phase stability performance of the wide-bandgap perovskite in this invention.

[0028] Figure 3 These are scanning electron microscope (SEM) images of the phase stability performance of the wide-bandgap perovskite in this invention.

[0029] Figure 4 This is a SEM image of the surface of the perovskite thin film doped with HABr-ThEABr in this invention.

[0030] Figure 5 This is a SEM image of the cross-section of the perovskite thin film doped with HABr-ThEABr in this invention.

[0031] Figure 6 This is a performance curve of the wide-bandgap perovskite solar cell of the present invention under AM 1.5G conditions;

[0032] Figure 7 This is a schematic diagram of the photoelectric properties of the wide-bandgap perovskite thin film of the present invention;

[0033] Figure 8 The JV curves of the undoped and HABr-ThEAB-doped wide-bandgap perovskite solar cells of this invention are shown under illumination conditions of 3800K and 1200lux.

[0034] Figure 9 This is a photograph of the wide-bandgap perovskite solar cell of Example 3 of the present invention and its JV curve under illumination conditions of 3800K and 1200 lux. Detailed Implementation

[0035] The present invention will be further described below with reference to embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0036] The transparent conductive substrate ITO used in the following examples was purchased from Liaoning Youxuan New Energy Technology Co., Ltd.; lead iodide (PbI2, purity 99.9%) and lead bromide (PbBr2, 99.9%) were purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd.; cesium iodide (CsI, 99.99%), lead thiocyanate (Pb(SCN)2, 99%), DMF, and DMSO were purchased from Sigma Aldrich; FAI was purchased from Greatcell Australia; and PTAA, HABr, and ThEABr were purchased from Xi'an Baolai Technology Co., Ltd.

[0037] Preparation of PTAA solution: Dissolve 4 mg PTAA in 1 ml chlorobenzene solution, stir thoroughly and filter.

[0038] Preparation of PFN-Br solution: Dissolve 5 mg PFN-Br in 20 mL anhydrous methanol and stir at 70 °C for 12 hours for later use.

[0039] Example 1

[0040] Fabrication of HAI-ThEAI-doped wide-bandgap perovskite indoor photovoltaic devices

[0041] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0042] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0043] S1 Preparation of Hole Transport Layer

[0044] S11 involves ultrasonically treating the transparent conductive substrate ITO with glass cleaner, deionized water, acetone, and anhydrous ethanol for 15 minutes each, followed by drying the ITO with dry nitrogen gas. The ITO surface is then treated with ultraviolet-ozone to enhance its hydrophilicity.

[0045] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0046] S2 Preparation of Wide-Band Perovskite Thin Films

[0047] S21 Preparation of Wide-Bandwidth Perovskite Precursor Solution

[0048] A molar concentration of 1.8 mol / mL-1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0049] S22 involves doping a wide-bandgap perovskite precursor solution to form perovskite precursor solution a.

[0050] 1% molar concentration of Pb(SCN)2 and 0.1% molar concentration of HAI were added to a wide-bandgap perovskite precursor solution for doping treatment to form perovskite precursor a solution. The solution was stirred thoroughly at room temperature for 2 hours and then filtered through a polytetrafluoroethylene filter membrane for later use.

[0051] S23 was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, acceleration 1000 r / s; 10 s before the end of the spin-coating program, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the surface of the liquid film as an antisolvent. After spin-coating, the film was placed on a heating stage at 100 °C for annealing for 15 min.

[0052] S3 undergoes surface passivation treatment.

[0053] S31 dissolves the surface passivation additive to prepare solution b.

[0054] Dissolve 3 mg ThEAI in anhydrous isopropanol solution, stir and filter to form solution b.

[0055] Solution b was spin-coated onto the wide-bandgap perovskite film of S2 using spin-coating parameters of 5000 rpm and 20 s. The film was then annealed on a heating stage at 100°C for 5 min.

[0056] S4 is used to prepare an electron transport layer.

[0057] An electron transport layer of C60 was deposited on a wide-bandgap perovskite film after S3 treatment using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0058] S5 Preparation of Hole Blocking Layer

[0059] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0060] S6 Preparation of Metal Electrodes

[0061] An Ag electrode was deposited on the hole blocking layer prepared by S5 using a vacuum thermal evaporation method at a deposition rate of 0.2 nm / s and a deposition thickness of 100 nm.

[0062] Example 2

[0063] Fabrication of wide-bandgap perovskite indoor photovoltaic devices doped with HABr-ThEABr

[0064] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0065] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0066] S1 Preparation of Hole Transport Layer

[0067] S11 involves ultrasonically treating the transparent conductive substrate ITO with glass cleaner, deionized water, acetone, and anhydrous ethanol for 15 minutes each, followed by drying the ITO with dry nitrogen gas. The ITO surface is then treated with ultraviolet-ozone to enhance its hydrophilicity.

[0068] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0069] S2 Preparation of Wide-Band Perovskite Thin Films

[0070] S21 Preparation of Wide-Bandwidth Perovskite Precursor Solution

[0071] A molar concentration of 1.8 mol / mL -1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0072] S22 involves doping a wide-bandgap perovskite precursor solution to form perovskite precursor solution a.

[0073] 1% molar concentration of Pb(SCN)2 and 0.1% molar concentration of HABr were added to a wide-bandgap perovskite precursor solution for doping treatment to form perovskite precursor a solution. The solution was stirred thoroughly at room temperature for 2 hours and then filtered through a polytetrafluoroethylene filter membrane for later use.

[0074] S23 was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, acceleration 1000 r / s; 10 s before the end of the spin-coating program, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the surface of the liquid film as an antisolvent. After spin-coating, the film was placed on a heating stage at 100 °C for annealing for 15 min.

[0075] S3 undergoes surface passivation treatment.

[0076] S31 dissolves the surface passivation additive to prepare solution b.

[0077] Dissolve 3 mg ThEABr in anhydrous isopropanol solution, stir and filter to form solution b.

[0078] Solution b was spin-coated onto the wide-bandgap perovskite film of S2 using spin-coating parameters of 5000 rpm and 20 s. The film was then annealed on a heating stage at 100°C for 5 min.

[0079] S4 is used to prepare an electron transport layer.

[0080] An electron transport layer of C60 was deposited on a wide-bandgap perovskite film after S3 treatment using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0081] S5 Preparation of Hole Blocking Layer

[0082] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0083] S6 Preparation of Metal Electrodes

[0084] An Ag electrode was deposited on the hole blocking layer prepared by S5 using a vacuum thermal evaporation method at a deposition rate of 0.2 nm / s and a deposition thickness of 100 nm.

[0085] Example 3

[0086] Large area (1cm) 2 Fabrication of wide-bandgap perovskite indoor photovoltaic devices doped with HABr-ThEABr

[0087] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0088] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0089] S1 Preparation of Hole Transport Layer

[0090] S11 will have an area of ​​1cm 2 The transparent conductive substrate ITO was ultrasonically treated for 15 minutes each in glass cleaner, deionized water, acetone, and anhydrous ethanol, and then dried with dry nitrogen gas. Afterwards, the ITO surface was treated with ultraviolet-ozone to improve its hydrophilicity.

[0091] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0092] S2 Preparation of Wide-Band Perovskite Thin Films

[0093] S21 Preparation of wide-bandgap perovskite precursor solution

[0094] A molar concentration of 1.8 mol / mL -1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0095] S22 involves doping a wide-bandgap perovskite precursor solution to form perovskite precursor solution a.

[0096] 1% molar concentration of Pb(SCN)2 and 0.1% molar concentration of HABr were added to a wide-bandgap perovskite precursor solution for doping treatment to form perovskite precursor a solution. The solution was stirred thoroughly at room temperature for 2 hours and then filtered through a polytetrafluoroethylene filter membrane for later use.

[0097] S23 was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, acceleration 1000 r / s; 10 s before the end of the spin-coating program, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the surface of the liquid film as an antisolvent. After spin-coating, the film was placed on a heating stage at 100 °C for annealing for 15 min.

[0098] S3 undergoes surface passivation treatment.

[0099] S31 dissolves the surface passivation additive to prepare solution b.

[0100] Dissolve 3 mg ThEABr in anhydrous isopropanol solution, stir and filter to form solution b.

[0101] Solution b was spin-coated onto the wide-bandgap perovskite film of S2 using spin-coating parameters of 5000 rpm and 20 s. The film was then annealed on a heating stage at 100°C for 5 min.

[0102] S4 is used to prepare an electron transport layer.

[0103] An electron transport layer of C60 was deposited on a wide-bandgap perovskite film after S3 treatment using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0104] S5 Preparation of Hole Blocking Layer

[0105] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0106] S6 Preparation of Metal Electrodes

[0107] An Ag electrode was deposited on the hole-blocking layer prepared in S5 using vacuum thermal evaporation at a deposition rate of 0.2 nm / s to a thickness of 100 nm. The evaporation of the Ag electrode using a specific mask resulted in an overlap area of ​​1 cm² between the Ag electrode and the ITO substrate. 2 Therefore, the effective area of ​​this large-area device is 1 cm². 2 .

[0108] Comparative Example 1

[0109] Fabrication of undoped wide-bandgap perovskite indoor photovoltaic devices

[0110] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0111] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0112] S1 Preparation of Hole Transport Layer

[0113] S11 involves ultrasonically treating the transparent conductive substrate ITO in glass cleaner, deionized water, acetone, and anhydrous ethanol for 15 minutes each, followed by drying the ITO with dry nitrogen gas. The ITO surface is then treated with ultraviolet-ozone to enhance its hydrophilicity.

[0114] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0115] S2 Preparation of Wide-Band Perovskite Thin Films

[0116] S21 Preparation of wide-bandgap perovskite precursor solution

[0117] A molar concentration of 1.8 mol / mL -1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0118] In S22, a wide-bandgap perovskite precursor solution was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, and acceleration 1000 r / s. Ten seconds before the end of the spin-coating process, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the film surface as an antisolvent. After spin-coating, the film was annealed on a heating stage at 100 °C for 15 min.

[0119] S3 fabrication of electron transport layer

[0120] An electron transport layer of C60 was deposited on a wide-bandgap perovskite film after S2 treatment using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0121] S4 prepares a hole-blocking layer

[0122] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S3 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0123] S5 Preparation of Metal Electrodes

[0124] An Ag electrode was deposited on the hole blocking layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.2 nm / s and a deposition thickness of 100 nm.

[0125] Comparative Example 2

[0126] Fabrication of wide-bandgap perovskite indoor photovoltaic devices doped only with HABr

[0127] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0128] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0129] S1 Preparation of Hole Transport Layer

[0130] S11 involves ultrasonically treating the transparent conductive substrate ITO in glass cleaner, deionized water, acetone, and anhydrous ethanol for 15 minutes each, followed by drying the ITO with dry nitrogen gas. The ITO surface is then treated with ultraviolet-ozone to enhance its hydrophilicity.

[0131] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0132] S2 Preparation of Wide-Band Perovskite Thin Films

[0133] S21 Preparation of wide-bandgap perovskite precursor solution

[0134] A molar concentration of 1.8 mol / mL -1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0135] S22 involves doping a wide-bandgap perovskite precursor solution to form perovskite precursor solution a.

[0136] 1% molar concentration of Pb(SCN)2 and 0.1% molar concentration of HABr were added to a wide-bandgap perovskite precursor solution for doping treatment to form perovskite precursor a solution. The solution was stirred thoroughly at room temperature for 2 hours and then filtered through a polytetrafluoroethylene filter membrane for later use.

[0137] S23 was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, acceleration 1000 r / s; 10 s before the end of the spin-coating program, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the surface of the liquid film as an antisolvent. After spin-coating, the film was placed on a heating stage at 100 °C for annealing for 15 min.

[0138] S3 fabrication of electron transport layer

[0139] An electron transport layer of C60 was deposited on a wide-bandgap perovskite thin film of S2 using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0140] S4 prepares a hole-blocking layer

[0141] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S3 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0142] S5 Preparation of Metal Electrodes

[0143] An Ag electrode was deposited on the hole blocking layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.2 nm / s and a deposition thickness of 100 nm.

[0144] Comparative Example 3

[0145] Fabrication of wide-bandgap perovskite indoor photovoltaic devices doped only with ThEABr

[0146] This invention utilizes an ITO / PTAA / PFN-Br / perovskite / C60 / BCP / Ag structure to fabricate a wide-bandgap perovskite indoor photovoltaic device.

[0147] The fabrication method of wide-bandgap perovskite indoor photovoltaic devices includes the following steps:

[0148] S1 Preparation of Hole Transport Layer

[0149] S11 involves ultrasonically treating the transparent conductive substrate ITO in glass cleaner, deionized water, acetone, and anhydrous ethanol for 15 minutes each, followed by drying the ITO with dry nitrogen gas. The ITO surface is then treated with ultraviolet-ozone to enhance its hydrophilicity.

[0150] S12: The ITO substrate was transferred to a nitrogen glove box. PTAA solution was spin-coated onto the ITO substrate at 4000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 10 min. After the PTAA cooled, PFN-Br solution was spin-coated onto the PTAA at 4000 rpm for 30 s. The substrate was then heated at 100°C for 10 s, and the next step of perovskite deposition was rapidly performed.

[0151] S2 Preparation of Wide-Band Perovskite Thin Films

[0152] S21 Preparation of wide-bandgap perovskite precursor solution

[0153] A molar concentration of 1.8 mol / mL -1 The perovskite materials FAI, CsI, PbI2, and PbBr2 were mixed in a molar ratio of 0.8:0.2:0.4:0.6 and dissolved in 1 mL of a mixed solution of DMF and DMSO with a volume ratio of 4:1 to obtain a wide-bandgap perovskite precursor solution.

[0154] In S22, a wide-bandgap perovskite precursor solution was spin-coated onto the hole transport layer of S1 to form a wide-bandgap perovskite film. The spin-coating conditions were: one-step spin-coating, rotation speed 4000 rpm, spin-coating time 30 s, and acceleration 1000 r / s. Ten seconds before the end of the spin-coating process, 200 μL of ethyl acetate (EA) was rapidly added dropwise to the film surface as an antisolvent. After spin-coating, the film was annealed on a heating stage at 100 °C for 15 min.

[0155] S3 undergoes surface passivation treatment.

[0156] S31 dissolves the surface passivation additive to prepare solution b.

[0157] Dissolve 3 mg ThEABr in anhydrous isopropanol solution, stir and filter to form solution b.

[0158] Solution b was spin-coated onto the wide-bandgap perovskite film of S2 using spin-coating parameters of 5000 rpm and 20 s. The film was then annealed on a heating stage at 100°C for 5 min.

[0159] S4 is used to prepare an electron transport layer.

[0160] An electron transport layer of C60 was deposited on a wide-bandgap perovskite film after S3 treatment using a vacuum thermal evaporation method. The deposition rate was 0.015-0.03 nm / s, and the deposition thickness was 30 nm.

[0161] S5 Preparation of Hole Blocking Layer

[0162] A hole blocking layer (BCP) was deposited on the electron transport layer prepared in S4 using a vacuum thermal evaporation method at a deposition rate of 0.02 nm / s and a deposition thickness of 5 nm.

[0163] S6 Preparation of Metal Electrodes

[0164] An Ag electrode was deposited on the hole blocking layer prepared by S5 using a vacuum thermal evaporation method at a deposition rate of 0.2 nm / s and a deposition thickness of 100 nm.

[0165] Performance testing

[0166] Figure 1 This is a curve showing the theoretical maximum efficiency of solar cells under different illumination conditions as a function of the bandgap width of the absorber layer material. Figure 1 (a) shows the relationship between the theoretical maximum efficiency of normal photovoltaic devices and indoor photovoltaic devices and the bandgap of the absorption layer; Figure 1 (b) in the figure is the Tauc plot curve of the perovskite thin film treated with HABr-ThEABr in this invention; Figure 1 As shown in (a), under sunlight irradiation conditions (AM 1.5G), to achieve the theoretically highest efficiency of a single-junction solar cell, the bandgap of the photovoltaic device's light-absorbing layer needs to be 1.34 eV. The relationship between the theoretically highest efficiency of indoor photovoltaic devices and the bandgap is calculated using commercial LED light strips. Indoor photovoltaic devices can achieve the theoretically highest efficiency at 1.79 eV. Figure 1 As shown in (b), the bandgap width is 1.80 eV, which is consistent with the bandgap width required for the theoretical maximum efficiency of indoor photovoltaics.

[0167] Figure 2 This is a graph showing the in-situ fluorescence spectroscopy test results of the phase stability performance of the wide-bandgap perovskite in this invention. Figure 2 (a) Fluorescence spectrum of undoped perovskite film under in-situ spectroscopic testing conditions; Figure 2 Image (b) shows the fluorescence spectrum of the HABr-ThEABr-doped perovskite film under in-situ spectroscopic testing conditions. Figure 2As shown in (a), under laser irradiation, the fluorescence peak of the undoped perovskite film continuously shifts towards longer wavelengths, indicating a decrease in the band gap of the perovskite material. This is mainly due to phase separation in the wide-bandgap perovskite under illumination, forming a bromine-rich phase (with a larger band gap) and an iodine-rich phase (with a smaller band gap). Figure 2 As shown in (b), after HABr-ThEABr doping, the position of the fluorescence peak of the wide-bandgap perovskite film did not change significantly under the same irradiation conditions, indicating that the phase separation of the wide-bandgap perovskite was suppressed and the phase stability was improved.

[0168] Figure 3 These are scanning electron microscope (SEM) images of the phase stability properties of the wide-bandgap perovskite in this invention. Figure 3 (a) shows SEM images of the undoped perovskite film before photoaging (left) and after photoaging (right). Figure 3 Image (b) shows SEM images of the HABr-ThEABr-doped perovskite film before and after photoaging (left image). Figure 3 As shown in (a), for undoped wide-bandgap perovskite films, after photoaging, the grains at the perovskite grain boundaries decompose, forming numerous small grains. Figure 3 As shown in (b), after HABr-ThEABr doping and photoaging, the morphology of the wide-bandgap perovskite film did not change, indicating that doping can improve the stability of the wide-bandgap perovskite film.

[0169] Figure 4 This is a SEM image of the surface of the HABr-ThEABr-doped perovskite film in this invention. Figure 4 It can be seen that a layer of plate-like material has formed on the surface of the perovskite. This is caused by the reaction between ThEABr and the perovskite material to form plate-like perovskite material. Figure 5 This is a SEM image of the cross-section of the HABr-ThEABr-doped perovskite thin film in this invention. Figure 5 It can be seen that the perovskite film in the vertical direction consists of a layer of high-quality perovskite grains.

[0170] Figure 6 This is a performance curve of the wide-bandgap perovskite thin film of the present invention under AM 1.5G conditions; Figure 6 (a) shows the results of undoped, HAI-ThEAI-doped, and HABr-ThEABr-doped wide-bandgap perovskite films at AM1.5 G and 100 mW / cm². 2 The JV curve under illumination conditions, by Figure 6As can be seen from (a) in [reference], their efficiencies are 15.25%, 17.89%, and 19.25% respectively, and the wide-bandgap perovskite solar cell doped with HABr-ThEABr has the highest efficiency. Figure 6 Figure (b) in [reference] shows the external quantum efficiency curves corresponding to undoped, HAI-ThEAI-doped, and HABr-ThEABr-doped wide-bandgap perovskite thin films. Figure 6 As can be seen from (b) in [reference], after doping with HABr-ThEABr, the wide-bandgap perovskite solar cell has the highest external quantum efficiency in the entire light absorption region.

[0171] Figure 7 It is a schematic diagram of the optoelectronic properties of the wide-bandgap perovskite thin film of the present invention; Figure 7 Figure (a) in [reference] shows the space charge limited current curves of undoped, HAI-ThEAI-doped, and HABr-ThEABr-doped wide-bandgap perovskite thin films. Figure 7 Figure (b) in [reference] shows the transient fluorescence spectra of undoped, HAI-ThEAI-doped, and HABr-ThEABr-doped wide-bandgap perovskite thin films. As can be seen from Figure 7 [reference] that the wide-bandgap perovskite thin film doped with HABr-ThEABr has the lowest space charge limited voltage, indicating the lowest density of defect states in this thin film; the wide-bandgap perovskite thin film doped with HABr-ThEABr has the longest carrier lifetime, which also benefits from the reduced density of defect states. It shows that the optoelectronic properties of the wide-bandgap perovskite thin film doped with HABr-ThEABr are better than those of undoped and HAI-ThEAI-doped wide-bandgap perovskite thin films.

[0172] Figure 8 It is the J-V curve diagram of the undoped and HABr-ThEAB-doped wide-bandgap perovskite solar cells of the present invention under the illumination conditions of 3800K and 1200lux; as can be seen from Figure 8 [reference] that under the illumination of a white LED with 3800K and 1200lux, the undoped wide-bandgap perovskite solar cell obtains an energy conversion efficiency of 33.18%, and the wide-bandgap perovskite solar cell doped with HABr-ThEABr obtains an energy conversion efficiency of 38.18%.

[0173] Figure 9 It is a photo of the wide-bandgap perovskite solar cell of Example 3 of the present invention and its J-V curve diagram under the illumination conditions of 3800K and 1200lux; as can be seen from Figure 9 [reference] that under the illumination of a white LED with 3800K and 1200lux, the wide-bandgap perovskite solar cell with an area of 1 cm 2 doped with HABr-ThEABr obtains an energy conversion efficiency of 31.33%.

[0174] In Comparative Example 2, the wide-bandgap perovskite indoor photovoltaic device doped only with HABr had an open-circuit voltage of 1.23V and a short-circuit current density of 17.04mA / cm². 2 The fill factor is 73.06%, and the power conversion efficiency is 15.33%. In Comparative Example 3, the wide-bandgap perovskite indoor photovoltaic device doped only with ThEABr has an open-circuit voltage of 1.21V and a short-circuit current density of 16.46mA / cm². 2 The fill factor is 77.14%, and the energy conversion efficiency is 15.39%. Therefore, the wide-bandgap perovskite film co-doped with HABr-ThEABr used in this invention exhibits good energy conversion efficiency.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for fabricating a high-efficiency, wide-bandgap perovskite indoor photovoltaic device, characterized in that: Includes the following steps: S1 Preparation of hole transport layer: After cleaning and drying the transparent conductive ITO substrate, it is treated with ultraviolet ozone or plasma. Hole transport material is spin-coated on the surface of the treated ITO substrate and then annealed to form a hole transport layer for later use. S2 Preparation of wide-bandgap perovskite thin film: Prepare wide-bandgap perovskite precursor solution, dope the wide-bandgap perovskite precursor solution to form perovskite precursor a solution, spin-coat the perovskite precursor a solution onto the hole transport layer of S1 to form wide-bandgap perovskite thin film, and anneal the wide-bandgap perovskite thin film. S3 undergoes passivation treatment: the surface passivation additive is dissolved to prepare solution b, solution b is spin-coated onto the wide-bandgap perovskite film of S2, and then annealed. S4 preparation of electron transport layer: deposit an electron transport layer on the wide-bandgap perovskite film after S3 treatment; S5 Preparation of Hole Blocking Layer: Hole blocking layer material is deposited on the electron transport layer prepared in S4; S6 Preparation of metal electrode: Deposit metal electrode on hole blocking layer prepared in S5; In S2, the doping process is carried out by using HAI or HABr. During the doping process, HAI and Pb(SCN)2 or HABr and Pb(SCN)2 are added to the wide-bandgap perovskite precursor solution for doping. The surface passivation additive in S3 is ThEAI or ThEABr; when the perovskite precursor solution a is doped with HAI, solution b is made by dissolving ThEAI in IPA and stirring until homogeneous; when the perovskite precursor solution a is doped with HABr, solution b is made by dissolving ThEABr in IPA and stirring until homogeneous.

2. The method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device according to claim 1, characterized in that: In step S1, the hole transport material is PTAA. The PTAA solution is spin-coated onto the ITO substrate and annealed at 100°C for 10 minutes. Then, a methanol solution of PFN-Br is spin-coated onto the PTAA surface to form a PTAA / PFN-Br hole transport layer. After annealing the hole transport layer at 100°C for 10 seconds, step S2 is immediately performed.

3. The method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device according to claim 1, characterized in that: In S2, a wide-bandgap perovskite precursor solution was prepared by mixing and dissolving FAI, CsI, PbI2, and PbBr2 in a mixed solution of DMF and DMSO, wherein the molar ratio of FAI, CsI, PbI2, and PbBr2 was 0.8:0.2:0.4:0.6, and the volume ratio of DMF to DMSO was 4:

1.

4. The method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device according to claim 1, characterized in that: The electron transport material in S4 is fullerene C60.

5. The method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device according to claim 1, characterized in that: The hole-blocking material in S5 is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline.

6. The method for fabricating a high-efficiency wide-bandgap perovskite indoor photovoltaic device according to claim 1, characterized in that: The metal electrode material in S6 is silver electrode, and the electrode thickness is 80-150nm.

7. A high-efficiency wide-bandgap perovskite indoor photovoltaic device prepared by the preparation method according to any one of claims 1-6.

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