Perovskite photovoltaic cell device and preparation method thereof

Abstract

The invention discloses a perovskite photovoltaic cell device and a preparation method thereof, belongs to a self-assembly monomolecular layer (SAM)-based trans-CsPbI2Br perovskite solar cell (PSCs) regulation and control technology, realizes interface defect passivation and energy level matching optimization through novel SAM molecules, solves the problem of low efficiency caused by interface defect and energy level mismatch of a traditional perovskite solar cell, and improves the efficiency of the traditional perovskite solar cell. Meanwhile, the invention provides a high-efficiency stable device which is low in cost and can be prepared in a large area and a preparation method.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a perovskite photovoltaic cell device and a preparation method thereof. Background Art

[0002] Perovskite solar cells (PSCs) are considered to be the core direction of the next generation of photovoltaic technology due to their high efficiency and low cost. Among them, the inorganic perovskite CsPbI2Br has an ideal band gap of 1.80-1.92 eV, which is suitable for single-junction and tandem solar cells, and its theoretical power conversion efficiency (PCE) can reach 24.3%. However, the current PCE of CsPbI2Br PSCs is only about 70% of the theoretical limit, which is mainly limited by two key issues: (1) Interface defects and carrier recombination: CsPbI2Br films prepared by low-temperature solution processing have a large number of bulk and interface defects, which lead to serious non-radiative recombination, reducing carrier lifetime and open circuit voltage (Voc). (2) Energy level mismatch and transport efficiency: the hole transport layer (such as NiO x ) and the electron transport layer have a poor energy level match with CsPbI2Br, and the interfacial charge accumulation triggers recombination losses, limiting the fill factor (FF) and stability.

[0003] Although existing interface optimization strategies can partially improve interface properties, they still have significant shortcomings: (1) The design of self-assembled monolayer (SAM) materials lacks systematicity: the types of commonly used phosphonic acid or carboxylic acid group SAM materials are limited, and the structure-activity relationship between molecular structure (such as electron-donating / withdrawing units, dipole moment) and device performance is not clear, making it difficult to optimize the interface energy level and defect passivation effect in a targeted manner. (2) Insufficient synergistic regulation of dual interfaces: Traditional methods focus on the bottom interface (NiO x Single modification of the interface (perovskite / perovskite) or the top interface (perovskite / electron transport layer) lacks synergistic optimization of both interfaces, making it difficult to fully suppress interfacial recombination and optimize carrier transport pathways. Therefore, it is urgent to address the efficiency loss caused by interface defects and the stability issues caused by energy level mismatch in existing technologies. Summary of the Invention

[0004] The purpose of the present invention is to provide a trans-CsPbI2Br perovskite solar cell (PSCs) control technology based on self-assembled monolayer (SAM). By using new SAM molecules to achieve interface defect passivation and energy level matching optimization, the problem of low efficiency of traditional perovskite solar cells caused by interface defects and energy level mismatch is solved. At the same time, a low-cost, large-area, efficient and stable device and preparation method are provided.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A perovskite photovoltaic cell device comprises a substrate, an anode layer, a hole transport layer, a SAM, a SAM-doped perovskite light absorption layer, a SAM, an electron transport layer, and a cathode layer stacked in sequence from bottom to top; the chemical structure of the SAM is: .

[0006] Furthermore, the concentration of SAM in the SAM-doped perovskite light absorbing layer is 0.3-0.8 wt %.

[0007] Preferably, the concentration of SAM in the SAM-doped perovskite light absorbing layer is 0.5 wt %.

[0008] Furthermore, the perovskite is CsPbI x Br 3-x , where x=2~3.

[0009] Furthermore, the hole transport layer includes a nickel oxide layer.

[0010] Furthermore, the electron transport layer includes fullerene C stacked in sequence from bottom to top. 60 Layer with 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0011] Furthermore, the hole transport layer also includes an electron blocking layer and / or an exciton blocking layer; and / or the electron transport layer also includes a hole blocking layer and / or an exciton blocking layer; and / or an anode buffer layer is further included between the anode layer and the hole transport layer; and / or a cathode buffer layer is further included between the cathode layer and the electron transport layer.

[0012] Furthermore, the anode layer and the cathode layer are metals or metal oxides or poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and modified products thereof.

[0013] Furthermore, the metal is aluminum, silver-magnesium alloy, silver or gold; and the metal oxide is one or a combination of two or more of indium tin oxide, fluorine-doped tin dioxide, zinc oxide and indium gallium zinc oxide.

[0014] Furthermore, the present invention also provides a method for preparing the above-mentioned perovskite photovoltaic cell device, comprising the following steps: S1) The substrate is ultrasonically cleaned using acetone, a micron-grade semiconductor detergent, deionized water, and isopropyl alcohol, followed by drying. S2) preparing an anode layer on the substrate; S3) depositing a hole transport layer on the anode layer by electron beam evaporation; S4) depositing a SAM on the hole transport layer; S5) depositing a SAM-doped perovskite light absorbing layer on the SAM; S6) depositing an electron transport layer on the SAM-doped perovskite light absorption layer by thermal evaporation; S7) preparing a cathode layer on the electron transport layer.

[0015] Furthermore, the method further includes forming an anode buffer layer between the anode layer and the hole transport layer; and / or depositing nickel oxide and / or an electron blocking layer and / or an exciton blocking layer on the anode layer as the hole transport layer; and / or depositing fullerene C on the SAM-doped perovskite light absorption layer. 60 A layer, a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer and / or a hole blocking layer and / or an exciton blocking layer are used as the electron transport layer; and / or a cathode buffer layer is formed between the electron transport layer and the cathode layer.

[0016] Specifically, an anode layer is formed on a substrate by evaporation, spin coating, sputtering or other methods.

[0017] Specifically, the SAM layer is formed on the surface of the hole transport layer by a solution spin coating method.

[0018] Specifically, the SAM-doped CsPbI x Br 3-x The precursor solution is spin-coated on the SAM layer and annealed to form a high-quality polycrystalline film.

[0019] Specifically, a SAM layer is formed on the surface of the SAM-doped perovskite light absorption layer by solution spin coating to passivate top interface defects and optimize energy level matching.

[0020] Beneficial effects:

[0021] (1) SAM molecules bind to the lead defects on the perovskite surface through functional anchoring groups (such as phosphonic acid groups). At the same time, through molecular structure design (such as introducing cyanide groups and adjusting electron-donating / withdrawing units), the interface energy level and dipole moment are regulated to achieve precise energy level matching with the transport layer.

[0022] (2) Through the synergistic modification of the bottom interface SAM layer (NiOx / CsPbI2Br) and the top interface SAM layer (CsPbI2Br / electron transport layer), double passivation of interface defects is achieved, non-radiative recombination losses are reduced, the carrier transport path is optimized, the open circuit voltage (Voc) and fill factor (FF) are significantly improved, and a PCE of more than 16% is achieved.

[0023] (3) By combining solution spin coating and evaporation processes, large-area uniform preparation of SAM-modified trans-CsPbI2Br PSCs was achieved, breaking through the bottlenecks of traditional devices in efficiency and environmental stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG1 is a diagram of the stacked structure of the perovskite solar cell device according to Example 1 of the present invention; Figure 2 1 is a current density-voltage characteristic curve of the perovskite solar cell device according to Example 1 of the present invention; Figure 3 This is a current density-voltage characteristic curve of the perovskite solar cell device according to Example 2 of the present invention; Figure 4 This is a current density-voltage characteristic curve of the perovskite solar cell device according to Example 3 of the present invention; Figure 5 This is a current density-voltage characteristic curve of the perovskite solar cell device of Comparative Example 1 of the present invention; Figure 6 This is a current density-voltage characteristic curve of the perovskite solar cell device of Comparative Example 2 of the present invention; Figure 7 This is a current density-voltage characteristic curve of the perovskite solar cell device of Comparative Example 3 of the present invention; Figure 8 This is a current density-voltage characteristic curve of the perovskite solar cell device of Comparative Example 4 of the present invention; Figure 9 This is a current density-voltage characteristic curve of the perovskite solar cell device of comparative example 5 of the present invention. DETAILED DESCRIPTION

[0025] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0026] The chemical structural formula of the SAM described below is: .

[0027] Example 1:

[0028] ITO conductive glass was selected as the substrate (ITO thickness of about 100 nm, sheet resistance of about 15 Ω / □). It was ultrasonically cleaned with acetone, a micron-grade semiconductor detergent (in this example, Alconox was used and prepared into a 1% aqueous solution), deionized water, and isopropyl alcohol for 20 minutes each to remove surface contaminants. The surface was then dried in an 80°C constant temperature oven. Nickel oxide (NiO) was prepared on the ITO substrate using electron beam evaporation. x ) Hole transport layer: NiOx The target material is used as the raw material, and thin film deposition is achieved by electron beam bombardment, followed by annealing at 300°C in air for 60 minutes; the device performance is optimized by adjusting the film thickness (10-110 nm), and the thickness of the hole transport layer is finally controlled to 30 nm.

[0029] Next, a solution method was used to prepare a self-assembled layer material SAM on the substrate after the above treatment. SAM was dissolved in methanol to prepare a solution with a concentration of 1 mg / mL, and then a self-assembled layer was formed on the substrate by solution spin coating. The perovskite light absorption layer was prepared by a solution method. The component of the perovskite was CsPbI2Br doped self-assembled material SAM (the concentration of SAM was 0.5wt%). Subsequently, a self-assembled monolayer SAM was used for interface modification: SAM molecules were dissolved in methanol (1 mg / mL), and a dense molecular layer was formed after solution spin coating, which effectively improved the interface contact performance. The device was transferred to the thermal evaporation equipment; when the vacuum degree of the evaporation chamber was reduced to 10 -4 Pa below, the electron transport layer C is deposited in sequence based on the mask. 60 (thickness 20-100nm, controlled to 60nm) and BCP layer (thickness 2-20nm, controlled to 5nm). Since both the hole transport layer and the electron transport layer are prepared by thermal evaporation, uniform film formation over a large area can be achieved. By changing the mask, battery devices of different sizes can be produced. Finally, metal Ag is evaporated as the cathode. The thickness is monitored in real time by a quartz crystal oscillator film thickness meter to control its thickness to ≥100nm. The final device structure is: glass / ITO / NiO x (30 nm) / SAM / CsPbI2Br+0.5wt%SAM / SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100nm).

[0030] Photovoltaic performance testing: After device fabrication, a Keithley 2400 source meter was used to measure the current-voltage characteristics. Light intensity data was combined to calculate parameters such as current density, fill factor, and power conversion efficiency (PCE). The device structure was optimized by analyzing these photovoltaic performance indicators.

[0031] Figure 2 The perovskite solar cell device (glass / ITO / NiO) obtained in Example 1 x (30 nm) / SAM / CsPbI2Br+SAM / SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0032] Example 2:

[0033] The only difference from Example 1 is that the perovskite component is CsPbI2Br doped self-assembled material SAM (SAM concentration is 0.3wt%), and the final device structure is: glass / ITO / NiO x (30 nm) / SAM / CsPbI2Br+0.3wt% SAM / SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0034] Figure 3 The perovskite solar cell device (glass / ITO / NiO) obtained in Example 2 x (30 nm) / SAM / CsPbI2Br+0.3wt% SAM / SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0035] Example 3:

[0036] The only difference from Example 1 is that the perovskite component is CsPbI2Br doped self-assembled material SAM (SAM concentration is 0.8wt%), and the final device structure is: glass / ITO / NiO x (30 nm) / SAM / CsPbI2Br+0.8wt% SAM / SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0037] Figure 4 The perovskite solar cell device (glass / ITO / NiO) obtained in Example 3 x (30 nm) / SAM / CsPbI2Br+0.8wt% SAM / SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0038] Comparative Example 1: The only difference from Example 1 is that it does not contain any self-assembled SAM layer, and the final device structure is: glass / ITO / NiO x (30 nm) / CsPbI2Br / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0039] Figure 5 The perovskite solar cell device (glass / ITO / NiO) obtained in Comparative Example 1 x (30 nm) / CsPbI2Br / C60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0040] Comparative Example 2: The only difference from Example 1 is that only in NiO x A self-assembled SAM layer is set on the layer, and the final device structure is: glass / ITO / NiO x (30 nm) / SAM / CsPbI2Br / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0041] Figure 6 The perovskite solar cell device (glass / ITO / NiO) obtained in Comparative Example 2 x (30 nm) / SAM / CsPbI2Br / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0042] Comparative Example 3: The only difference from Example 1 is that SAM is doped only in the perovskite layer, and the final device structure is: glass / ITO / NiO x (30 nm) / CsPbI2Br+0.5wt% SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0043] Figure 7 The perovskite solar cell device (glass / ITO / NiO) obtained in Comparative Example 3 x (30 nm) / CsPbI2Br+0.5wt% SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0044] Comparative Example 4: The only difference from Example 1 is that only a self-assembled SAM layer is provided on the perovskite layer, and the final device structure is: glass / ITO / NiO x (30 nm) / CsPbI2Br / SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100 nm).

[0045] Figure 8 The perovskite solar cell device (glass / ITO / NiO) obtained in Comparative Example 4 x(30 nm) / CsPbI2Br / SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0046] Comparative Example 5: The only difference from Example 1 is that only in NiO x layer and a self-assembled SAM layer is set on the perovskite layer. The final device structure is: glass / ITO / NiO x (30 nm) / SAM / CsPbI2Br / SAM / C 60 (60 nm) / BCP (5 nm) / Ag (100nm).

[0047] Figure 9 The perovskite solar cell device (glass / ITO / NiO) obtained in Comparative Example 5 x (30 nm) / SAM / CsPbI2Br / SAM / C 60 Current density-voltage characteristic curve of (60 nm) / BCP (5 nm) / Ag (100 nm)).

[0048] Table 1 shows the comparison results of photovoltaic performance parameters of the perovskite solar cell devices in Example 1 and Comparative Examples 1-4.

[0049] Table 1 Comparison results of photovoltaic performance parameters

[0050] Open circuit voltage (V) Fill factor (%) <![CDATA[Short-circuit current (mA / cm -2 )]]> Solar energy conversion rate (%) Example 1 1.17 83.94 16.32 16.03 Example 2 1.14 81.68 16.32 15.20 Example 3 1.15 82.15 16.34 15.44 Comparative Example 1 0.98 75.37 15.83 11.69 Comparative Example 2 1.11 80.13 16.27 14.47 Comparative Example 3 1.10 78.58 16.31 14.10 Comparative Example 4 1.15 79.76 16.29 14.94 Comparative Example 5 1.15 80.53 16.28 15.08

[0051] As shown in Table 1, in Comparative Example 1, no self-assembled layer (SAM) was introduced for interface modification. The open circuit voltage of the device was 0.98 V, which is relatively low, indicating that the potential difference maintained across the battery is small in the absence of light. The fill factor was 75.37%, indicating that there is room for improvement in the efficiency of energy collection and utilization in actual operation. The short-circuit current was 15.83 mA / cm 2 , reflecting that under illumination conditions, the maximum current intensity that the battery can generate is relatively limited; finally, the solar energy conversion efficiency is only 11.69%, which indicates that the battery has a weak ability to convert the received solar energy into electrical energy; overall, various indicators in Example 1 and Comparative Examples 1-4 are at a relatively low level, indicating that when no special interface optimization and other treatments are performed, the photoelectric performance of the device has certain limitations.

[0052] Comparative Example 2 introduces SAM for interface modification; at this time, the open circuit voltage increases to 1.11V, which is significantly higher than that of Comparative Example 1. This means that the battery can maintain a higher potential difference in the absence of light, providing more favorable conditions for subsequent power generation; the fill factor reaches 80.13%, indicating that the battery's efficiency in collecting and utilizing power has been improved, and the generated power can be output more effectively; the short-circuit current is 16.27mA / cm 2 , which is an increase compared with Comparative Example 1, indicating that the battery can generate a stronger current under light; finally, the solar energy conversion efficiency reaches 14.47%, which is a significant improvement compared with Comparative Example 1; this fully demonstrates that SAM optimizes the interface performance of the battery, improves the charge transfer process, and thus improves the overall photoelectric performance.

[0053] Comparative Example 3 doped the perovskite layer with 0.5wt% SAM material. The open circuit voltage was 1.10V, which was higher than that of Comparative Example 1 but slightly lower than that of Comparative Example 2. The fill factor was 78.58%, which was also lower than that of Comparative Example 2. The short circuit current was 16.31mA / cm 2 , but the overall improvement effect is limited; the solar energy conversion efficiency is 14.10%, which is also slightly lower than that of Comparative Example 2; this shows that simply doping the perovskite layer with SAM material is not as effective in optimizing device performance as introducing SAM for interface modification, because the doped SAM material does not improve the key processes such as charge transfer and recombination at the interface as effectively as the SAM layer.

[0054] Comparative Example 4 again uses SAM interface modification; the open circuit voltage is 1.15V, continuing to maintain a high level, further proving the positive effect of SAM on improving the open circuit voltage; the fill factor is 79.76%, and the short circuit current is 16.29m / cm 2 , the solar energy conversion efficiency is 14.94%; these data once again verify that SAM can effectively regulate the interface of perovskite cells, thereby effectively improving the various performance indicators of the device, which is of great significance to improving the photoelectric performance of perovskite solar cells.

[0055] Example 1 simultaneously introduces SAM interface modification and perovskite layer doping with 0.5wt% SAM material; its open circuit voltage reaches a maximum value of 1.17V, which further increases the potential difference that the battery can maintain in the absence of light; the fill factor is 83.94%, the highest among all examples and comparative examples, indicating that the battery has achieved optimal efficiency in collecting and utilizing electrical energy; the short-circuit current is 16.32mA / cm 2, slightly improved; the solar energy conversion efficiency reached 16.03%, which was significantly higher than other comparison examples; this fully demonstrates that the synergistic effect of interface optimization (SAM modification) and material doping (perovskite layer doped with SAM material) can effectively improve the charge transport inside the battery, reduce charge recombination, etc., greatly improving the open circuit voltage, fill factor, short-circuit current and solar energy conversion efficiency, and significantly improving the photoelectric performance of perovskite solar cells.

[0056] A systematic comparison and analysis of data from various examples and comparative examples demonstrates that both self-assembled layer (SAM) interface modification technology and SAM material doping strategies in the perovskite layer play a key role in improving the performance of perovskite solar cells. Particularly noteworthy is the significant synergistic coupling effect achieved when these two approaches are used synergistically: not only achieving breakthroughs in key parameters such as open-circuit voltage, short-circuit current, and fill factor, but also reshaping the internal carrier behavior of the cell from the perspective of charge dynamics. From a device structural perspective, this combined strategy enables precise control of the energy level matching between the functional layers. The SAM optimizes the interface energy level alignment, creating a low-barrier channel that facilitates efficient hole transport. SAM material doping modulates the perovskite layer band structure, promoting directional electron extraction and migration. The synergistic effect of these two approaches effectively reduces charge recombination losses at the interface, creating a "high-speed channel" for hole and electron transport, enabling efficient carrier separation and collection during the device's photoelectric conversion process. This synergistic optimization ultimately drives a qualitative leap in device performance, providing a highly promising technological path towards the industrialization of perovskite solar cells.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A perovskite photovoltaic cell device, characterized in that: The invention comprises a substrate, an anode layer, a hole transport layer, a SAM, a SAM-doped perovskite light absorption layer, a SAM, an electron transport layer and a cathode layer stacked in sequence from bottom to top; the chemical structure of the SAM is: 。 2. The perovskite photovoltaic cell device according to claim 1, characterized in that The concentration of SAM in the SAM-doped perovskite light absorption layer is 0.3~0.8wt%.

3. The perovskite photovoltaic cell device according to claim 1, characterized in that: The perovskite is CsPbI x Br 3-x , where x=2~3.

4. The perovskite photovoltaic cell device according to claim 1, characterized in that: The hole transport layer includes a nickel oxide layer.

5. The perovskite photovoltaic cell device according to claim 1, characterized in that: The electron transport layer includes fullerene C stacked sequentially from bottom to top. 60 Layer with 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline.

6. The perovskite photovoltaic cell device according to claim 1, characterized in that: The hole transport layer further includes an electron blocking layer and / or an exciton blocking layer; and / or the electron transport layer further includes a hole blocking layer and / or an exciton blocking layer; and / or an anode buffer layer is further included between the anode layer and the hole transport layer; and / or a cathode buffer layer is further included between the cathode layer and the electron transport layer.

7. The perovskite photovoltaic cell device according to claim 1, characterized in that: The anode layer and the cathode layer are metal or metal oxide or poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonic acid) and modified products thereof.

8. The perovskite photovoltaic cell device according to claim 7, characterized in that: The metal is aluminum, silver-magnesium alloy, silver or gold; the metal oxide is one or a combination of two or more of indium tin oxide, fluorine-doped tin dioxide, zinc oxide and indium gallium zinc oxide.

9. A method for preparing a perovskite photovoltaic cell device according to any one of claims 1 to 8, characterized in that: The steps include: S1) The substrate is ultrasonically cleaned using acetone, a micron-grade semiconductor detergent, deionized water, and isopropyl alcohol, followed by drying. S2) preparing an anode layer on the substrate; S3) depositing a hole transport layer on the anode layer by electron beam evaporation; S4) depositing a SAM on the hole transport layer; S5) depositing a SAM-doped perovskite light absorbing layer on the SAM; S6) depositing an electron transport layer on the SAM-doped perovskite light absorption layer by thermal evaporation; S7) preparing a cathode layer on the electron transport layer.

10. The preparation method according to claim 9, characterized in that The method further includes forming an anode buffer layer between the anode layer and the hole transport layer; and / or depositing nickel oxide and / or an electron blocking layer and / or an exciton blocking layer on the anode layer as the hole transport layer; and / or depositing fullerene C on the SAM-doped perovskite light absorption layer. 60 A layer, a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline layer and / or a hole blocking layer and / or an exciton blocking layer are used as the electron transport layer; and / or a cathode buffer layer is formed between the electron transport layer and the cathode layer.

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