Preparation method for effectively reducing defects of perovskite solar cell body

Abstract

The invention discloses a preparation method for effectively reducing defects of a perovskite solar cell body. A 4-fluorobenzenesulfonamide additive is introduced into a perovskite precursor solution, a sulfonyl group, a fluorine group and the like are coordinated with lead in perovskite, the crystallization process of the film is regulated and controlled, nucleation and crystal growth of an organic lead halide perovskite light absorption layer are effectively controlled, meanwhile, non-radiative recombination is inhibited, charge transfer is promoted, and the photoelectric conversion efficiency is improved. The photoelectric conversion efficiency is obviously improved, the cost is reduced and the repeatability is good. The additive is introduced by a solution method, the process is simple and the cost is low. Experimental results show that after the 4-fluorobenzenesulfonamide additive is used, the trap state density of a perovskite layer is reduced from 4.45 * 10 < 15 > cm <-3 > to 3.26 * 10 < 15 > cm <-3 >, and the photoelectric conversion efficiency of a perovskite cell is improved from 22.20% to 24.15%. The invention provides an efficient and low-cost solution for defect passivation of the perovskite solar cell.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite solar cells, and particularly relates to a preparation method for effectively reducing the bulk defects of perovskite solar cells. Background Art

[0002] Energy is an important driving force for promoting the development of human society. With the rapid advancement of the world's industrialization process and the global population growth, the demand for and consumption of energy are constantly increasing. However, currently, we mainly rely on traditional energy sources such as coal and oil, which are finite and non-renewable fossil energy. At the same time, the large carbon emissions, which affect the natural environment, such as the greenhouse effect, the melting of Antarctic glaciers, etc., have sounded the alarm for humanity, and the reserves are limited. Therefore, to solve the current energy problems, we must change the existing energy structure and actively develop and utilize new renewable and environmentally friendly energy sources. As an emerging energy source, solar energy stands out among many renewable energy sources. It has many advantages such as being inexhaustible, pollution-free, zero carbon emissions, safe and reliable, and widely distributed, and is considered to be one of the most effective ways to solve the world's current energy problems.

[0003] In recent years, organic-inorganic halide perovskite solar cells (PSCs) have received extensive attention due to their characteristics such as high efficiency and low cost. In the past decade or so, the power conversion efficiency (PCE) of PSCs has experienced a significant increase, from 3.8% to the certified value of 27.0%. Although PSCs have a bright future in next-generation photovoltaic power generation, due to their easy degradation under environmental conditions and the potential negative impact of the toxic lead component on the environment, they still have the problem of poor operational stability. To address this problem, the additive strategy is a widely used and effective crystallization regulation method. Additives can interact with uncoordinated metal cations or halide anions, inhibit the formation of defects or reduce the defect density, change the chemical environment of the perovskite precursor and the properties of the intermediate phase, and improve the quality of the perovskite thin film.

[0004] Currently, the widely used passivation materials are mainly insulating polymers. Although these materials can passivate some defects in perovskite, there are also some limitations. Their insulating properties will inhibit the effective collection of photogenerated carriers by the perovskite light-absorbing layer, thereby affecting the PCE of the device. And many passivation materials only contain a single functional group and lack hydrophobic groups, making it difficult for these materials to effectively block the intrusion of moisture in the air, resulting in poor stability of the device in a humid environment and reducing its service life. Summary of the Invention

[0005] To solve the above problems existing in the prior art, the present invention provides a preparation method for effectively reducing the bulk defects of perovskite solar cells.

[0006] Technical solution of the present invention: A preparation method for effectively reducing the bulk defects of perovskite solar cells, which successively includes a conductive glass, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a buffer layer, and a metal back electrode from bottom to top. A 4-fluorobenzenesulfonamide additive is added to the perovskite light-absorbing layer.

[0007] Among them, the small molecule structure of the passivating defect additive includes a sulfonyl group, an amino group, a benzene ring, and a fluorine group.

[0008] The concentration of the perovskite additive is 0.2 mg / ml to 0.8 mg / ml.

[0009] A preparation method for effectively reducing the bulk defects of perovskite solar cells, comprising the following steps: Step 1: Ultrasonically treat the conductive glass successively with a detergent, deionized water, and isopropanol, then blow it dry, and then perform ultraviolet ozone treatment, and take it out for standby; Step 2: Spin-coat the prepared MeO-4PACz solution on the pretreated ITO substrate, and then anneal it to obtain a hole transport layer; Step 3: Dissolve the perovskite light-absorbing layer material in a mixed solvent of DMF and DMSO to obtain a perovskite precursor solution, then add 4-fluorobenzenesulfonamide, shake and filter it, and then spin-coat it on the hole transport layer, and then anneal it. Before the spin-coating of the perovskite precursor solution ends, chlorobenzene is dropped; Step 4: Spin-coat the prepared PCBM solution on the perovskite light-absorbing layer obtained in Step 3 to obtain an electron transport layer; Step 5: Spin-coat the prepared BCP solution on the electron transport layer obtained in Step 4 to obtain a buffer layer; Step 6: Under high vacuum, thermally evaporate a metal back electrode on the buffer layer obtained in Step 5.

[0010] Furthermore, in Step 1, the conductive glass is ITO or FTO, the time of the ultrasonic treatment is 20 min, and the time of the ozone treatment is 15 to 20 min.

[0011] Furthermore, in Step 2, the annealing temperature is 100 °C and the time is 10 min.

[0012] Furthermore, in Step 3, the perovskite light-absorbing layer material is an organic amine salt and a lead halide salt, and the volume ratio of DMF to DMSO is 4:1.

[0013] Furthermore, in Step 4, the spin-coating speed is 3000 rpm and the spin-coating time is 30 s.

[0014] Further, in the step 5, the metal back electrode is gold, silver, copper or aluminum, and the evaporation thickness is 80 nm.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention uses 4-fluorobenzenesulfonamide as an additive, and through the coordination of sulfonyl group and fluorine group with lead in perovskite, the crystallization process of the film is regulated, and the nucleation and crystal growth of the organic lead halide perovskite light absorption layer are effectively controlled; 2. It helps to inhibit charge recombination and promote charge transport; 3. The photoelectric conversion efficiency is significantly improved, the cost is reduced, the repeatability is good, and it has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the perovskite solar cell of the present invention.

[0017] Figure 2 It is a comparison result diagram of the X-ray diffraction pattern of the perovskite of the present invention.

[0018] Figure 3 It is a comparison result diagram of the steady-state photoluminescence intensity of the perovskite of the present invention.

[0019] Figure 4 It is a comparison result diagram of the water contact angle of the perovskite of the present invention.

[0020] Figure 5 It is a single electron device of the present invention J-V Comparison result diagram of the curve.

[0021] Figure 6 It is a comparison result diagram of the short-circuit current density and open-circuit voltage curves of the perovskite solar cell of the present invention. SPECIFIC EMBODIMENTS

[0022] Comparative Example A preparation method for effectively reducing the body defects of perovskite solar cells, comprising the following steps: (1) The ITO conductive substrate is ultrasonically treated with detergent, deionized water, and isopropanol for 20 min in sequence, then dried, and then treated with ultraviolet ozone for 20 min, and taken out for standby; (2) 0.5 mg of Me-4PACz is dissolved in ethanol, spin-coated at a speed of 30 s, 3000 r / min (acceleration is 1000 r / min / s), and then annealed at 100 °C for 10 min to prepare a hole transport layer; (3) FAI (219 mg), MAI (23.8 mg), MACl (12.7 mg), PbI 2(760.7 mg) and CsI (19.5 mg) were dissolved in a mixed solution of DMF and DMSO (VDMF:VDMSO = 4:1). After shaking for 5 min, the perovskite precursor solution was dropped onto the hole transport layer prepared in step (2). First, it was spin-coated at a speed of 10 s, 1000 r / min (acceleration of 1000 r / min / s), and then at a speed of 40 s, 4000 r / min (acceleration of 4000 r / min / s). At the remaining 5 s, 150 μL of chlorobenzene antisolvent was added, and then annealed at 100 °C for 30 min to obtain the perovskite light-absorbing layer; (4) 20 mg of PCBM was dissolved in chlorobenzene and spin-coated on the perovskite layer prepared in step (3) at a speed of 30 s, 3000 r / min (acceleration of 3000 r / min / s), and then annealed at 100 °C for 10 min to obtain the electron transport layer; (5) 0.5 mg of BCP was dissolved in isopropanol and spin-coated on the electron transport layer prepared in step (4) at a speed of 30 s, 4000 r / min (acceleration of 4000 r / min / s) to obtain the buffer layer; (6) Under high vacuum (10 -4 Pa), an Ag electrode with a thickness of 80 nm was thermally evaporated onto the buffer layer prepared in step (5), and that's it. Example

[0023] A method for preparing a perovskite solar cell doped with 4-fluorobenzenesulfonamide passivator, which is different from the comparative example in that in step (3), the concentration of the perovskite precursor solution added with 4-fluorobenzenesulfonamide is 0.25 mg / mL.

[0024] Figure 1 It is a schematic diagram of the structure of the perovskite solar cell of the comparative example; Figure 2 It is the Pb 4f XPS spectrum of the perovskite in the comparative example and Example 1. It can be seen that the Pb 4f energy level of the perovskite in Example 1 shifts to a lower energy level, indicating that there is a strong interaction between the 4-fluorobenzenesulfonamide molecule and the uncoordinated Pb 2+ and effectively passivates the defects in the perovskite film; Figure 3 It is the steady-state photoluminescence intensity of the perovskite measured in the comparative example and Example 1. It can be seen that the PL intensity of the perovskite in Example 1 is significantly improved, inhibiting non-radiative recombination and reducing perovskite body defects; Figure 4 It is the water contact angle of the perovskite measured in the comparative example and Example 1. It can be seen that the water contact angle of the perovskite in Example 1 increases from 48.14 to 63.75, improving the stability of the perovskite film; Figure 5 For the single-electron devices measured in the comparative example and Example 1 J-V curve, it can be seen that the V of the device in Example 1 TFL decreases from 0.13 V to 0.11 V, and the perovskite trap state density decreases from 4.45×10 15 cm -3 to 3.26×10 15 cm -3 , and the electron mobility increases from 7.69×10 -5 cm 2 V -1 s -1 to 1.80×10 -4 cm 2 V -1 s -1 .

[0025] Figure 6 For the short-circuit current density and open-circuit voltage curves of the perovskite solar cells in the comparative example and Example 1 measured under AM 1.5G sunlight, it can be seen that the photoelectric conversion efficiency of the perovskite solar cell in Example 1 increases from 22.20% to 24.15%.

[0026] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell that effectively reduces defects, characterized in that: From bottom to top, there are conductive glass, hole transport layer, perovskite light absorption layer, electron transport layer, buffer layer and metal back electrode. The perovskite light absorption layer is added with 4-fluorobenzenesulfonamide additive.

2. The small molecular structure of the additive includes sulfonyl group, amino group, benzene ring and fluorine group.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The concentration of the additive is 0.2 mg / ml to 0.8 mg / ml.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The perovskite precursor solution is a precursor solution of an ABX3 type perovskite material, wherein A is at least one of Cs, MA, and FA, B is Pb and / or Sn, and X is at least one of Cl, Br, and I.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The following steps are involved: Step 1, treating the conductive glass with detergent, deionized water, and isopropyl alcohol in sequence, then drying it with air, and then treating it with ultraviolet ozone, and then taking it out for use; Step 2, spin coating the prepared MeO-4PACz solution on the pretreated ITO substrate, followed by annealing to obtain a hole transport layer; Step 3, dissolving the perovskite light absorbing layer material in a mixed solvent of DMF and DMSO to obtain a perovskite precursor solution, then adding 4-fluorobenzenesulfonamide, shaking, filtering, and then spin-coating on the hole transport layer, followed by annealing, and before the perovskite precursor solution is spin-coated, chlorobenzene is added dropwise; Step 4, spin coating the prepared PCBM solution onto the perovskite light absorbing layer prepared in step 3 to prepare an electron transport layer; Step 5, spin coating the prepared BCP solution onto the electron transport layer prepared in step 4 to prepare a buffer layer; Step 6: Deposit a metal back electrode on the buffer layer prepared in step 5 by thermal evaporation under high vacuum.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step 1, the conductive glass is ITO or FTO, the ultrasonic treatment time is 20 min, and the ozone treatment time is 15 to 20 min.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In step 2, the annealing temperature is 100° C. and the time is 10 min.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step 3, the perovskite light-absorbing layer materials are organic amine salts and lead halide salts, and the volume ratio of DMF to DMSO is 4:

1.

9. The method for preparing a perovskite solar cell according to claim 5, characterized in that: The spin coating speed in step 4 is 3000 rpm, and the spin coating time is 30 s.

10. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In step 5, the metal back electrode is gold, silver, copper or aluminum, and the evaporation thickness is 80 nm.

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