A pin type perovskite solar cell and a preparation method thereof

Abstract

This invention relates to a PIN-type perovskite solar cell and its fabrication method, belonging to the field of photovoltaic technology. The solar cell structure, from bottom to top, comprises: an ITO transparent conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, and an Ag back electrode. The perovskite active layer is a Cs₀.₀₅FA₀.₉MA₀.₀₅PbI₃ with a band gap of 1.55 eV, and contains diallyl trisulfide as an additive, with a final concentration of 0.05–0.5 mg / mL. This PIN-type perovskite solar cell and its fabrication method effectively suppress non-radiative recombination and water-oxygen erosion of the perovskite film through the strong coordination and hydrophobicity of DATS, improving the photoelectric conversion efficiency and long-term stability of the device. Furthermore, the process is compatible with solution processing and low-temperature preparation, facilitating industrial scale-up and solving the technical problems of numerous defects and poor stability in existing PIN-type perovskite cells.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a 1.55eV bandgap PIN perovskite solar cell containing diallyl trisulfide (DATS) additive and its preparation method, particularly to the preparation of the perovskite active layer and optimization of device performance using a one-step spin-coating process with the amount of DATS added as a variable, which is suitable for the large-scale preparation of high-efficiency and stable perovskite solar cells. Background Technology

[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their outstanding advantages such as tunable bandgap, high light absorption coefficient, strong solution processability, and low manufacturing cost. Their photoelectric conversion efficiency (PCE) has rapidly exceeded 26%, demonstrating enormous industrialization potential. PIN-type perovskite solar cells, with a core structure of "hole transport layer / perovskite active layer / electron transport layer," do not require high-temperature annealing processes, are suitable for flexible substrates and low-temperature mass production, and are more in line with the needs of industrial applications compared to traditional nip structures.

[0003] 1.55 eV bandgap perovskite materials (such as CsO). 05 FA0.9MA0. 05 PbI3) balances efficient absorption in the visible light region with a high open-circuit voltage (V). o (c) This material maximizes the utilization of solar spectrum energy while minimizing carrier recombination losses, making it a preferred active layer material for single-junction and tandem perovskite solar cells. However, current 1.55 eV bandgap PIN perovskite solar cells still face core technological bottlenecks: perovskite films are prone to forming numerous grain boundaries and surface defects (such as uncoordinated Pb²⁺ and iodine vacancies) during solution processing. These defects can trigger severe nonradiative recombination, reducing carrier transport efficiency and intensifying ion migration, significantly affecting device efficiency and long-term stability. Furthermore, perovskite materials are highly hydrophilic and susceptible to water and oxygen corrosion, further shortening device lifespan.

[0004] To address the aforementioned defects, existing technologies often employ organic additives to modify the perovskite active layer. Sulfur-containing organic molecules, due to the strong lone pair electrons of their sulfur atoms, can form stable coordination bonds with uncoordinated Pb²⁺ in the perovskite, achieving defect passivation. Simultaneously, the hydrophobicity of some sulfur-containing molecules can improve the film's water and oxygen stability. Currently reported sulfur-containing additives mainly include diallyl disulfide and thiols, but their coordination ability is limited, and the defect passivation effect and stability improvement still need further optimization.

[0005] Diallyl trisulfide (DATS, CAS: 2050-87-5) is an organosulfur compound containing trisulfide bonds. Compared to traditional sulfur-containing additives, its molecular structure contains more S atoms that can participate in coordination, resulting in stronger coordination ability and more efficient passivation of defects in perovskite films. Simultaneously, DATS molecules possess good hydrophobicity, forming hydrophobic barriers at perovskite grain boundaries, effectively inhibiting water and oxygen intrusion and ion migration. Currently, there are no reports on systematic studies of using DATS as an additive in PIN-type perovskite solar cells with a 1.55 eV bandgap fabricated via one-step spin-coating. The effects of its addition amount on the morphology, defect state density, and photoelectric performance of the perovskite film urgently need to be clarified, and the related fabrication process has not yet formed a standardized scheme, limiting its industrial application.

[0006] Based on this, the present invention proposes a 1.55 eV bandgap PIN perovskite solar cell containing DATS additive and its preparation method. By using the amount of DATS added as a variable, the crystallization process and defect state of the perovskite thin film are precisely controlled through a one-step spin coating process, so as to achieve simultaneous improvement in device efficiency and stability, fill the gap in the existing technology, and provide a preparation scheme that is easy to industrialize. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a PIN-type perovskite solar cell and its preparation method. By introducing DATS as an additive into the perovskite active layer, and using the amount of DATS added as a variable, combined with a one-step spin-coating process, defect passivation, crystallization control, and stability improvement of the perovskite thin film are achieved, resulting in a high-efficiency and stable PIN-type perovskite solar cell. At the same time, the preparation process is simplified, production costs are reduced, and it is suitable for large-scale production needs.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A PIN-type perovskite solar cell, wherein the structure of the solar cell, from bottom to top, comprises: an ITO transparent conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, and an Ag back electrode;

[0010] The perovskite active layer is CsO with a band gap of 1.55 eV. 05 FA0.9MA0. 05 PbI3, and containing diallyl trisulfide additive, wherein the final concentration of diallyl trisulfide is 0.05–0.5 mg / mL.

[0011] Furthermore, the hole transport layer is PEDOT:PSS or NiO. x The hole transport layer has a thickness of 25–35 nm; the electron transport layer is C 60 / BCP composite structure, where C60 The thickness of the electrode is 18–22 nm, the thickness of the BCP is 6–10 nm, the thickness of the Ag back electrode is 90–110 nm, and the area of ​​the Ag back electrode is 0.08–0.10 cm².

[0012] Furthermore, the thickness of the perovskite active layer is 400–500 nm, and the sheet resistance of the ITO transparent conductive substrate is 10–15 Ω / sq, with a thickness of 1.0–1.2 mm.

[0013] Another technical problem to be solved by the present invention is to provide a method for fabricating a PIN-type perovskite solar cell, comprising the following steps:

[0014] S1. Cleaning and pretreatment of ITO transparent conductive substrate: The ITO glass was ultrasonically cleaned with detergent, deionized water, acetone and isopropanol for 15 min each, dried with nitrogen, and then treated with ultraviolet ozone for 30 min.

[0015] S2. Hole transport layer preparation: After filtering the PEDOT:PSS solution, spin-coat it onto the surface of the ITO transparent conductive substrate at 4000 rpm for 30 s, anneal at 150℃ for 15 min, and then transfer it to a nitrogen glove box for cooling.

[0016] S3. Preparation of perovskite active layer: Prepare 1.55 eV bandgap perovskite precursor solutions containing different concentrations of DATS. Take 80 μL of the precursor solution and spin-coat it onto the surface of the hole transport layer. The spin-coating parameters are 1000 rpm for 10 s → 5000 rpm for 40 s. Add 200 μL of chlorobenzene antisolvent in the last 5 s of spin-coating and anneal at 100℃ for 10 min.

[0017] S4. Electron transport layer fabrication: Under a vacuum degree ≤ 5 × 10⁻⁻ 4 Under Pa conditions, C is deposited sequentially. 60 Together with BCP, they form a composite electron transport layer;

[0018] S5. Ag back electrode fabrication and packaging: Under the same vacuum conditions, Ag back electrode is deposited by vapor deposition, packaged and stored in the dark under nitrogen protection to complete device fabrication.

[0019] Furthermore, the solvent of the perovskite precursor solution is DMF:DMSO = 4:1, and the solutes of the perovskite precursor solution include CsI (0.05 M), FAI (0.9 M), MAI (0.05 M), PbI2 (1.05 M), and MACl (10 mg / mL). The DATS purity of the perovskite precursor solution is ≥99%.

[0020] Furthermore, the perovskite precursor solution is prepared by adding the solute sequentially to the mixed solvent, stirring at 60°C for 12 h until completely dissolved, filtering with a 0.22 μm PTFE filter, and then storing under nitrogen protection.

[0021] Furthermore, the rotation speed of the first stage of spin coating can be adjusted to 800–1200 rpm, and the rotation speed of the second stage of spin coating can be adjusted to 4000–6000 rpm; the annealing temperature can be adjusted to 90–110℃, and the annealing time can be adjusted to 8–12 min.

[0022] Furthermore, the antisolvent can be replaced with toluene or diethyl ether, in an amount of 180–220 μL; the C 60 The evaporation rates are 0.4–0.6 Å / s, BCP evaporation rates are 0.2–0.4 Å / s, and Ag evaporation rates are 0.8–1.2 Å / s.

[0023] Compared with the prior art, the present invention provides a PIN-type perovskite solar cell and its preparation method, which has the following beneficial effects:

[0024] 1. This PIN-type perovskite solar cell and its fabrication method utilize the trisulfide bonds in the DATS molecule, which contain multiple coordinating sulfur atoms. These atoms can form stable coordination bonds with uncoordinated Pb²⁺ and iodine vacancies in the perovskite film, effectively passivating grain boundaries and surface defects, suppressing nonradiative recombination, and significantly improving the open-circuit voltage (V). o c) and fill factor (FF), thereby improving photoelectric conversion efficiency.

[0025] 2. The PIN perovskite solar cell and its fabrication method: DATS can be used as a template for perovskite crystallization, inducing an increase in perovskite grain size and a decrease in the number of grain boundaries, thereby improving the film density and crystal quality, optimizing carrier transport channels, reducing carrier scattering and recombination, and further improving device efficiency.

[0026] 3. The PIN-type perovskite solar cell and its preparation method: DATS molecules have good hydrophobicity and can form a hydrophobic barrier at the perovskite grain boundaries, effectively inhibiting water and oxygen intrusion and ion migration, significantly improving the light stability, thermal stability and humidity stability of the device, and extending the device's lifespan.

[0027] 4. The PIN perovskite solar cell and its preparation method use a one-step spin-coating process to prepare the perovskite active layer. This process requires no complex equipment, is simple and low-cost, and allows for precise control of the DATS addition amount. It is also suitable for low-temperature and solution processing technologies and is easy to scale up for mass production.

[0028] 5. The PIN perovskite solar cell and its preparation method, by using DATS as an additive in a 1.55 eV bandgap PIN perovskite cell, clarified the influence of its addition amount on device performance, filled the gap in existing technology, and provided a new technical path for the preparation of high-efficiency and stable perovskite cells. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1: (Preparation of PIN perovskite solar cells with DATS concentration of 0.05 mg / mL)

[0031] A method for fabricating a PIN-type perovskite solar cell includes the following steps:

[0032] S1. Cleaning and pretreatment of ITO transparent conductive substrate: ITO glass (15 mm × 15 mm, sheet resistance 12 Ω / sq) was ultrasonically cleaned with detergent, deionized water, acetone and isopropanol for 15 min each, dried with nitrogen and treated with UV-O3 for 30 min.

[0033] S2. Hole transport layer preparation: PEDOT:PSS solution was filtered through a 0.45 μm filter, spin-coated at 4000 rpm for 30 s, annealed at 150℃ for 15 min, and then transferred to a nitrogen glove box for cooling.

[0034] S3, preparation of perovskite precursor solution: Prepare Cs0 according to the basic formula. 05 FA0.9MA0. 05 PbI3 precursor solution, add DATS to make a final concentration of 0.05 mg / mL, stir at 60℃ for 12 h, filter and keep under nitrogen protection for later use;

[0035] S4. Preparation of perovskite active layer: Take 80 μL of the above precursor solution, spin coat at 1000 rpm for 10 s → spin coat at 5000 rpm for 40 s, add 200 μL of chlorobenzene in the last 5 s, and anneal at 100℃ for 10 min.

[0036] S5, Electron transport layer preparation: Vacuum evaporation of C 60 (20 nm, 0.5 Å / s), BCP (8 nm, 0.3 Å / s);

[0037] S6. Ag back electrode preparation and packaging: Ag electrode (100 nm, 1 Å / s) was deposited by vapor deposition, packaged and stored in the dark, and the device performance was tested.

[0038] Example 2: (Preparation of PIN perovskite solar cells with DATS concentration of 0.2 mg / mL)

[0039] The preparation method is exactly the same as in Example 1, except that the final concentration of DATS in the perovskite precursor solution is changed to 0.2 mg / mL, and the other process parameters remain unchanged.

[0040] Example 3: (Preparation of PIN perovskite solar cells with DATS concentration of 0.5 mg / mL)

[0041] The preparation method is exactly the same as in Example 1, except that the final concentration of DATS in the perovskite precursor solution is changed to 0.5 mg / mL, and the other process parameters remain unchanged.

[0042] Control group: (Preparation of PIN perovskite solar cells without DATS additives)

[0043] The preparation method is exactly the same as in Example 1, except that a DATS-free basic perovskite precursor solution is used, and the other process parameters remain unchanged.

[0044] Performance test results:

[0045] The photoelectric performance of the solar cells in Examples 1–3 and the control group was tested (AM 1.5G, 100 mW / cm²), and the test results are shown in Table 1.

[0046] Table 1

[0047] sample control group Example 1 Example 2 Example 3 DATS concentration (mg / mL) 0 0.05 0.2 0.5 <![CDATA[Open circuit voltage V o c (V)]]> 1.02 1.05 1.08 1.06 <![CDATA[Short-circuit current J s c (mA / cm²)]]> 23.5 23.8 24.2 23.7 Fill factor FF (%) 72.3 75.1 78.5 76.2 Photoelectric conversion efficiency (PCE) (%) 17.2 18.7 20.5 19.3 30-day stability retention rate (%) 62.1 78.3 86.7 82.5

[0048] Test results show that when the concentration of DATS is 0.2 mg / mL, the device performance is optimal, with a photoelectric conversion efficiency of 20.5% and a 30-day stability retention rate of 86.7%. Compared with the control group, the efficiency is improved by 19.2% and the stability retention rate is improved by 39.6%, which fully demonstrates that DATS additive can effectively improve the efficiency and stability of the device, and there is an optimal concentration range.

[0049] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A PIN-type perovskite solar cell, characterized in that, The structure of the solar cell, from bottom to top, consists of: an ITO transparent conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer, and an Ag back electrode. The perovskite active layer is CsO with a band gap of 1.55 eV. 05 FA0.9MA0. 05 PbI3, and containing diallyl trisulfide additive, wherein the final concentration of diallyl trisulfide is 0.05–0.5 mg / mL.

2. The PIN-type perovskite solar cell according to claim 1, characterized in that, The hole transport layer is PEDOT:PSS or NiO. x The hole transport layer has a thickness of 25–35 nm; the electron transport layer is C 60 / BCP composite structure, where C 60 The thickness of the electrode is 18–22 nm, the thickness of the BCP is 6–10 nm, the thickness of the Ag back electrode is 90–110 nm, and the area of ​​the Ag back electrode is 0.08–0.10 cm².

3. A PIN-type perovskite solar cell according to claim 1, characterized in that, The thickness of the perovskite active layer is 400–500 nm, and the sheet resistance of the ITO transparent conductive substrate is 10–15 Ω / sq, with a thickness of 1.0–1.2 mm.

4. A method for preparing a PIN-type perovskite solar cell, applicable to the preparation of the PIN-type perovskite solar cell according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Cleaning and pretreatment of ITO transparent conductive substrate: The ITO glass was ultrasonically cleaned with detergent, deionized water, acetone and isopropanol for 15 min each, dried with nitrogen, and then treated with ultraviolet ozone for 30 min. S2. Hole transport layer preparation: After filtering the PEDOT:PSS solution, spin-coat it onto the surface of the ITO transparent conductive substrate at 4000 rpm for 30 s, anneal at 150℃ for 15 min, and then transfer it to a nitrogen glove box for cooling. S3. Preparation of perovskite active layer: Prepare perovskite precursor solutions with different concentrations of DATS at a band gap of 1.55 eV. Take 80 μL of the precursor solution and spin-coat it onto the surface of the hole transport layer. The spin-coating parameters are 1000 rpm for 10 s → 5000 rpm for 40 s. Add 200 μL of chlorobenzene antisolvent in the last 5 s of spin-coating and anneal at 100℃ for 10 min. S4. Electron transport layer fabrication: Under a vacuum degree ≤ 5 × 10⁻⁻ 4 Under Pa conditions, C is deposited sequentially. 60 Together with BCP, they form a composite electron transport layer; S5. Ag back electrode fabrication and packaging: Under the same vacuum conditions, Ag back electrode is deposited by vapor deposition, packaged and stored in the dark under nitrogen protection to complete device fabrication.

5. The method for fabricating a PIN-type perovskite solar cell according to claim 4, characterized in that, The solvent of the perovskite precursor solution is DMF:DMSO = 4:1, and the solutes of the perovskite precursor solution include CsI (0.05 M), FAI (0.9 M), MAI (0.05 M), PbI2 (1.05 M), and MACl (10 mg / mL). The DATS purity of the perovskite precursor solution is ≥99%.

6. The method for preparing a PIN-type perovskite solar cell according to claim 4, characterized in that, The perovskite precursor solution is prepared by adding the solute sequentially to the mixed solvent, stirring at 60°C for 12 h until completely dissolved, filtering through a 0.22 μm PTFE filter, and storing under nitrogen protection.

7. The method for fabricating a PIN-type perovskite solar cell according to claim 4, characterized in that, The rotation speed of the first stage of spin coating can be adjusted to 800–1200 rpm, and the rotation speed of the second stage of spin coating can be adjusted to 4000–6000 rpm; the annealing temperature can be adjusted to 90–110℃, and the annealing time can be adjusted to 8–12 min.

8. The method for fabricating a PIN-type perovskite solar cell according to claim 4, characterized in that, The antisolvent can be replaced with toluene or diethyl ether, in an amount of 180–220 μL; the C 60 The evaporation rates are 0.4–0.6 Å / s, BCP evaporation rates are 0.2–0.4 Å / s, and Ag evaporation rates are 0.8–1.2 Å / s.