Lead halide hybrid perovskite solar cells with lanthanide-salen complex interfacial layer as radical scavenger

Abstract

The application discloses a lead halide hybrid perovskite solar cell with a lanthanide metal-Salen complex interface layer as a free radical scavenger, which comprises, from bottom to top, a substrate layer, a transparent conductive metal oxide layer, an electron transport layer, a perovskite layer, an Ln-Salen complex interface layer, a hole transport layer and a metal electrode layer. The photovoltaic performance and stability of the perovskite solar cell prepared by using the Ln-Salen complex are improved. As an interface layer between the perovskite layer and the hole transport layer, the Ln-Salen complex has uncoordinated functional groups or atoms, which can be combined with the under-coordinated Pb 2+ Ions on the surface of the perovskite layer, thereby reducing the defects on the surface of the perovskite layer. Meanwhile, the substance has good oxidation resistance and can scavenge O2 ·‑ O2 ·‑ Produced by O2, avoids the reaction of O2 with the perovskite, and inhibits the degradation of the perovskite layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optoelectronic materials and devices, and particularly relates to a lead halide hybrid perovskite solar cell with a lanthanide metal-Salen complex interface layer as a free radical scavenger. BACKGROUND

[0002] Perovskite solar cells have attracted extensive attention due to their solution processing, low cost and high photovoltaic performance. Currently, the highest certified power conversion efficiency of perovskite solar cells has reached 26.7%, but there is still a gap with the Shockley-Queisser theoretical limit. This is because the solution-prepared perovskite thin film surface has a large number of defects, such as under-coordinated ion defects, vacancy defects and grain boundary defects. These defects will form recombination sites for photo-generated carriers, hinder carrier transport, and thus result in low power conversion efficiency of perovskite solar cells. In addition, the stability of perovskite thin film is also an important factor affecting the photovoltaic performance of perovskite solar cells. Many studies have shown that the reaction of perovskite with O2 ·- can accelerate the degradation process of perovskite, making the stability of perovskite solar cells worse. For example, it is found in the document "Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells" [1] that the perovskite thin film exposed to air and light will form O2 ·- , resulting in degradation of perovskite thin film and affecting the photovoltaic performance of perovskite solar cells. Therefore, it is urgent to find a substance that can not only eliminate O2 ·- , but also passivate the surface defects of perovskite thin film, to improve the photovoltaic performance of perovskite solar cells.

[0003] Small organic molecules or polymers are usually passivation agents for the surface of perovskite thin film. On the one hand, small molecules or polymers can interact with perovskite to reduce the surface defects of perovskite thin film. On the other hand, hydrophobic small molecules or polymers can block water in the environment from entering perovskite. In the document "Hydrophobic fluorinated conjugated polymer as a multifunctional interlayer for high-performance perovskite solar cells" [2]A fluorinated conjugated polymer 3,4-difluorothiophene (PTzNDI-2FT) was synthesized and used as an interfacial layer for perovskite / Spiro-OMeTAD. In addition to improving the hydrophobicity of perovskite film, the carbonyl group in PTzNDI-2FT can interact with uncoordinated Pb 2+ in perovskite, passivate trap states, and prolong the carrier lifetime. The perovskite solar cells with interfacial modification obtained a 23.2% power conversion efficiency and showed high environmental and thermal stability. Literature "A multifunctional polymer as an interfacial layer for efficient and stable perovskite solar cells" [3] A multifunctional polymethyl methacrylate-co-acrylamide (PMMA-AM) was designed and used as an interfacial layer for perovskite / Spiro-OMeTAD. The ester and amide groups in PMMA-AM can not only interact with uncoordinated Pb 2+ in perovskite, but also the amide can form hydrogen bonds with I - to inhibit I - migration and inhibit the formation of vacancy defects. The open-circuit voltage of the device was significantly improved from 1.12 V to 1.22 V after interfacial modification and a 23.24% power conversion efficiency was obtained. In addition, modifying the surface of 3D perovskite with 2D perovskite layer is also an effective strategy to improve the power conversion efficiency and stability of perovskite solar cells. Literature "Stable Layered 2D Perovskite Solar Cells with an Efficiency of over 19% via Multifunctional Interfacial Engineering" [4] Bromoguanidine was selected as an interfacial layer for perovskite and hole transport layer. It was found that bromoguanidine could induce perovskite film to recrystallize to form 2D perovskite, reducing the surface defects of perovskite film. The power conversion efficiency of perovskite solar cells with interfacial modification increased from 15.9% to 19.3% and showed excellent environmental stability. Although small molecules or polymers and 2D perovskite layer modifying the surface of 3D perovskite can improve the photovoltaic performance and stability of perovskite solar cells, they do not solve the problem of O2 ·- influencing the photovoltaic performance of perovskite solar cells under light conditions.

[0004] REFERENCES

[0005] 1. Aristidou N, Eames C, Sanchez-Molina I, et al. Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells [J]. Nature communications, 2017, 8(1): 15218.

[0006] 2. Li Y, Lim E L, Xie H, et al. Hydrophobic fluorinated conjugated polymer as a multifunctional interlayer for high-performance perovskite solar cells [J]. ACS Photonics, 2021, 8(11): 3185-3192. 3. Zhang B, Chen C, Wang X, et al. A multifunctional polymer as an interfacial layer for efficient and stable perovskite solar cells [J]. Angewandte Chemie International Edition, 2023, 62(2): e202213478.

[0007] 4. Huang Y, Li Y, Lim E L, et al. Stable layered 2D perovskite solar cells with an efficiency of over 19% via multifunctional interfacial engineering [J]. Journal of the American Chemical Society, 2021, 143(10): 3911-3917. SUMMARY

[0008] Based on the problems existing in the prior art, the present application provides a lead halide hybrid perovskite solar cell with a lanthanide metal-Salen (Ln-Salen) complex interface layer as a free radical scavenger to improve the photovoltaic performance and stability of the perovskite solar cell.

[0009] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0010] The application provides a lead halide hybrid perovskite solar cell with a lanthanide metal-Salen complex interface layer as a free radical scavenger, the lead halide hybrid perovskite solar cell comprising a substrate layer, a transparent conductive metal oxide layer, an electron transport layer, a perovskite layer, an Ln-Salen complex interface layer, a hole transport layer, and a metal electrode layer.

[0011] Further, the Ln-Salen complex is one of [Sm(Salen)(NO3)3], [Eu(Salen)(NO3)3] and [Dy(Salen)(NO3)3], wherein Salen is bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine. · - .

[0012] Further, the Ln-Salen complex interface layer is prepared by a spin coating method, and the concentration of a spin coating precursor solution (a complex is added to a solvent to form a required precursor solution) used is 0.01-5 mg / mL, and the solvent is one or more of toluene, chlorobenzene, methanol, ethanol and isopropanol.

[0013] Further, the substrate layer is glass, quartz, flexible polyethylene terephthalate or flexible polyethylene naphthalate.

[0014] Further, the transparent conductive metal oxide layer is fluorine-doped tin oxide or indium-doped tin oxide.

[0015] Further, the electron transport layer is tin oxide, titanium oxide or zinc oxide.

[0016] Further, the perovskite layer is Cs x (FA 1-y MA y ) 1-x Pb(I z Br 1-z )3, wherein 0≤x≤1, 0≤y≤1 and 0≤z≤1.

[0017] Further, the hole transport layer is 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene.

[0018] Further, the metal electrode layer is a gold electrode or a silver electrode.

[0019] The beneficial effects of the application are embodied in:

[0020] Ln-Salen complexes are passivating agents with antioxidant and coordination capabilities. They are used as an interface layer on the upper surface of the perovskite layer in perovskite solar cells. On one hand, the uncoordinated -C=N- and O in the Ln-Salen complex can interact with the undercoordinated Pb. 2+ Ion bonding passivates surface defects; on the other hand, Ln-Salen complexes possess antioxidant properties and can remove O2 generated by O2. ·- Avoid O2 · - The reaction with the perovskite layer inhibits its degradation, thereby improving the stability of the perovskite film. The perovskite solar cells prepared using the Ln-Salen complex in this invention exhibit improved photovoltaic performance and stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the lead halide hybrid perovskite solar cell of the present invention and a schematic diagram of the passivation mechanism of the Ln-Salen complex interface;

[0022] Figure 2 The JV curve is shown for the lead halide hybrid perovskite solar cell prepared in Example 1.

[0023] Figure 3 The JV curve is shown for the lead halide hybrid perovskite solar cell prepared in Example 2.

[0024] Figure 4 The JV curve is shown for the lead halide hybrid perovskite solar cell prepared in Example 3.

[0025] Figure 5 The light stability of the lead halide hybrid perovskite solar cells prepared in Example 4 and Comparative Example 1 is shown. Detailed Implementation

[0026] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention and not for limiting the claims of the present invention.

[0027] Example 1

[0028] This embodiment provides a lead halide hybrid perovskite solar cell using a [Eu(Salen)(NO3)3] complex interface layer as a free radical scavenger, and its preparation steps are as follows:

[0029] (1) Etching and cleaning FTO conductive glass: After etching the FTO conductive glass with zinc powder and hydrochloric acid, ultrasonically clean the FTO conductive glass with detergent, anhydrous ethanol, acetone and deionized water in sequence, and finally dry it with nitrogen gas for later use.

[0030] (2) Preparation of the electron transport layer: SnO2 aqueous solution (mass ratio of SnO2 to H2O is 1:4.2) was spin-coated on the FTO conductive glass at a speed of 3000 rpm for 30 s, and then annealed at 200 °C for 1 h to form the electron transport layer.

[0031] (3) Preparation of the perovskite layer: 44.5 mg of MAI, 192.6 mg of FAI, 677.7 mg of PbI2, and 20.26 mg of MACl were dissolved in 1 mL of a mixed solvent of DMF and DMSO (volume ratio of DMF to DMSO is 8:1) to obtain a perovskite precursor solution, which was spin-coated on the FTO / SnO2 substrate at a speed of 1000 rpm for 10 s in the first step and at a speed of 5000 rpm for 50 s in the second step. 200 μL of toluene antisolvent was added 10-30 s before the end of the second step. After spin-coating, the sample was annealed at 150 °C for 0.5 h to form the perovskite layer.

[0032] (4) Preparation of the complex interface layer:

[0033] The preparation of [Eu(Salen)(NO3)3] refers to the method in the reference “Tang X, Shi X, Xu Y, et al. Synthesis, Crystal Structure, Fluorescent and Antioxidation Properties of Cerium(III) and Europium(III) Complexes with Bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine [J]. Zeitschrift für anorganische und allgemeine Chemie, 2017, 643(5): 379-386.”. The sample in the corresponding literature is [Eu(Bod)(NO3)3].

[0034] [Eu(Salen)(NO3)3] was added to toluene to prepare a [Eu(Salen)(NO3)3] solution with a concentration of 0.15 mg / mL, which was spin-coated on the perovskite film at a speed of 3000 rpm for 30 s, and then annealed at 50 °C for 12 min to form the complex interface layer.

[0035] (5) Preparation of hole transport layer: The hole transport layer solution (containing 72.3 mg 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 28.8 μL 4-tert-butylpyridine, and 17.5 μL bis(trifluoromethanesulfonyl)imide lithium salt (520 mg / mL) acetonitrile solution, 1 mL chlorobenzene) was spin-coated on the complex interface layer at a speed of 4000 rpm for 30 s to form the hole transport layer.

[0036] (6) Preparation of metal electrode layer: The sample was placed in a vacuum evaporation device to evaporate a 60 nm thick Au electrode by a thermal evaporation process, i.e., the preparation of the perovskite solar cell was completed.

[0037] The cell was tested under the condition of AM1.5 and an active layer effective area of 0.04 cm -2 , and the J-V curve is shown in Figure 2 . It can be seen that the sample obtained an open-circuit voltage of 1.05 V, a short-circuit current density of 24.20 mAcm -2 , a fill factor of 78.1%, and a photoelectric conversion efficiency of 19.76%.

[0038] Example 2

[0039] This example provides a lead halide hybrid perovskite solar cell with a [Sm(Salen)(NO3)3] complex interface layer as a free radical scavenger, and the preparation steps are as follows:

[0040] (1) Etching and cleaning FTO conductive glass: the same as in Example 1.

[0041] (2) Preparation of electron transport layer: The cleaned FTO conductive glass was placed in a 0.04 M TiCl4 aqueous solution, kept in a 70°C oven for 0.5 h, rinsed with deionized water, dried with nitrogen, and kept on a 200°C heating table for 1 h to deposit a TiO2 thin film.

[0042] (3) Preparation of perovskite layer: 10.9 mg of CsI, 11.97 mg of MAI, 221.5 mg of FAI, 677.7 mg of PbI2, and 20.26 mg of MACl were dissolved in 1 mL of a mixed solvent of DMF and DMSO (volume ratio of DMF to DMSO being 8:1) to obtain a perovskite precursor solution, which was spin-coated on the FTO / TiO2 substrate, the first step being set at a speed of 1000 rpm for 10 s, and the second step being set at a speed of 5000 rpm for 50 s, 200 mL of toluene anti-solvent being added dropwise 10-30 s before the end of the second step, and the spin-coated sample being annealed at 150°C for 0.5 h to form a perovskite layer.

[0043] (4) Preparation of complex interface layer:

[0044] The preparation of [Sm(Salen)(NO3)3] refers to the method in the reference literature "Shi X, Mao S, Shen K, et al. Synthesis, crystal structure, antioxidation and fluorescence of two lanthanide complexes with a noncyclic polyether Schiff base ligand [J]. Journal of Coordination Chemistry, 2017, 70(12): 2015-2028.", and the sample in the corresponding literature is [Sm(Bod)(NO3)3].

[0045] [Sm(Salen)(NO3)3] was added to toluene to prepare a [Sm(Salen)(NO3)3] solution with a concentration of 0.50 mg / mL, which was spin-coated on the perovskite film at a speed of 3000 rpm for 30 s. After spin-coating, the sample was annealed at 90℃ for 6 min to form the complex interface layer.

[0046] (5) Preparation of hole transport layer: same as Example 1.

[0047] (6) Preparation of metal electrode layer: same as Example 1.

[0048] The battery was tested under the conditions of AM1.5 and an active layer effective area of 0.04 cm -2 . The J-V curve is shown in Figure 3 . It can be seen that the sample obtained an open-circuit voltage of 1.08 V, a short-circuit current density of 24.42 mAcm -2 , a fill factor of 80.6%, and a photoelectric conversion efficiency of 21.36%.

[0049] Example 3

[0050] This example provides a lead halide hybrid perovskite solar cell with [Dy(Salen)(NO3)3] complex interface layer as a free radical scavenger, and the preparation steps are as follows:

[0051] (1) Etching and cleaning FTO conductive glass: same as Example 1.

[0052] (2) Preparation of electron transport layer: same as Example 1.

[0053] (3) Preparation of perovskite layer: 222.5 mg of MAI, 677.7 mg of PbI2, and 10.26 mg of MACl were weighed and dissolved in 1 mL of a mixed solvent of DMF and DMSO, wherein the volume ratio of DMF to DMSO was 8:1, to obtain a perovskite precursor solution, which was spin-coated on an FTO / SnO2 substrate, the first step was set to 1000 rpm for 10 s, and the second step was set to 5000 rpm for 50 s, 200 mL of toluene anti-solvent was added dropwise 10-30 s before the end of the second step, and the perovskite layer was formed after spin-coating and annealing at 100°C for 0.5 h.

[0054] (4) Preparation of complex interface layer:

[0055] The preparation of [Dy(Salen)(NO3)3] refers to the method in the reference "Li C F, Xu Y L, Bai Y C, et al. Synthesis, Crystal Structure, Antioxidation, and Luminescence of a Mononuclear Dysprosium(III) Complex Based on the Bis(3-Methoxysalicylidene)-3-Oxapentane-1, 5-Diamine Ligand [J]. Koordinatsionnaya Khimiya, 2017, 43(1): 54-62.", and the sample in the corresponding literature is [Dy(Bod)(NO3)3].

[0056] [Dy(Salen)(NO3)3] was added to toluene to prepare a [Dy(Salen)(NO3)3] solution with a concentration of 1.0 mg / mL, which was spin-coated on the perovskite film with a rotation speed of 3000 rpm for 30 s, and the complex interface layer was formed after spin-coating and annealing at 60°C for 24 min.

[0057] (5) Preparation of hole transport layer: same as Example 1.

[0058] (6) Preparation of metal electrode layer: same as Example 1.

[0059] The battery was tested under the conditions of AM1.5 and an active layer effective area of 0.04 cm -2 , and the J-V curve is shown in Figure 4 . It can be seen that the sample obtained an open-circuit voltage of 1.02 V, a short-circuit current density of 23.50 mAcm -2 , a fill factor of 75.5%, and a photoelectric conversion efficiency of 18.10%.

[0060] Example 4

[0061] The embodiment provides a lead halide hybrid perovskite solar cell with a [Sm(Salen)(NO3)3] complex interface layer as a free radical scavenger, and the preparation steps are as follows:

[0062] (1) Etching and cleaning FTO conductive glass: the same as in embodiment 1.

[0063] (2) Preparation of an electron transport layer: the same as in embodiment 1.

[0064] (3) Preparation of a perovskite layer: the same as in embodiment 1.

[0065] (4) Preparation of a complex interface layer: [Sm(Salen)(NO3)3] is added to toluene to prepare a [Sm(Salen)(NO3)3] solution with a concentration of 0.15 mg / mL, which is spin-coated on the perovskite thin film at a speed of 3000 rpm for 30 s, and then annealed at 50 DEG C for 12 min after spin-coating to form a complex interface layer.

[0066] (5) Preparation of a hole transport layer: the same as in embodiment 1.

[0067] (6) Preparation of a metal electrode layer: the same as in embodiment 1.

[0068] The battery is tested under the condition of AM1.5 and an active layer effective area of 0.04 cm -2 , and the sample obtains an open circuit voltage of 1.07 V, a short circuit current density of 24.15 mAcm -2 , a fill factor of 81.9%, and a photoelectric conversion efficiency of 21.10%. Figure 5 is the light stability of the battery tested under the condition of AM1.5, and it can be seen that the light stability of the sample is obviously higher than that of comparative example 1.

[0069] Embodiment 5

[0070] The embodiment provides a lead halide hybrid perovskite solar cell with a [Dy(Salen)(NO3)3] complex interface layer as a free radical scavenger, and the preparation steps are as follows:

[0071] (1) Etching and cleaning FTO conductive glass: the same as in embodiment 1.

[0072] (2) Preparation of an electron transport layer: the same as in embodiment 1.

[0073] (3) Preparation of a perovskite layer: the same as in embodiment 1.

[0074] (4) Preparation of the complex interface layer: [Dy(Salen)(NO3)3] was added to toluene to prepare a [Dy(Salen)(NO3)3] solution with a concentration of 0.15 mg / mL, which was spin-coated on the perovskite film at a rotation speed of 3000 rpm for 30 s, and then annealed at 50°C for 12 min to form the complex interface layer.

[0075] (5) Preparation of the hole transport layer: same as in Example 1.

[0076] (6) Preparation of the metal electrode layer: same as in Example 1.

[0077] The battery was tested under AM1.5, with an active layer effective area of 0.04 cm -2 , and the sample obtained an open-circuit voltage of 1.04 V, a short-circuit current density of 24.16 mA cm -2 , a fill factor of 80.8%, and a photoelectric conversion efficiency of 20.40%.

[0078] Comparative Example 1

[0079] A lead halide hybrid perovskite solar cell was prepared according to the same method as in Example 1, except that no complex interface layer was provided between the perovskite layer and the hole transport layer.

[0080] The battery was tested under AM1.5, with an active layer effective area of 0.04 cm -2 , and the sample obtained an open-circuit voltage of 0.99 V, a short-circuit current density of 24.11 mA cm -2 , a fill factor of 76.8%, and a photoelectric conversion efficiency of 18.29%.

[0081] The above description is only exemplary embodiments of the present application, and does not limit the present application in any way. Any modification and equivalent variation made according to the method of the present application still falls within the scope of protection of the present application.

Claims

1. A lead halide hybrid perovskite solar cell with a lanthanide metal-Salen complex interfacial layer as a radical scavenger, said lead halide hybrid perovskite solar cell comprising a substrate layer, a transparent conductive metal oxide layer, an electron transport layer, a perovskite layer, a hole transport layer, a metal electrode layer, characterized in that: An Ln-Salen complex interface layer is further arranged between the perovskite layer and the hole transport layer; the Ln-Salen complex is one of [Sm(Salen)(NO3)3], [Eu(Salen)(NO3)3] and [Dy(Salen)(NO3)3], wherein Salen is bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine.

2. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The Ln-Salen complex interface layer has antioxidant properties and can eliminate O2 generated by O2 ·- .

3. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The Ln-Salen complex interface layer is prepared by a spin coating method, and the concentration of a spin coating precursor solution used is 0.01-5 mg / mL, and the solvent is one or more of toluene, chlorobenzene, methanol, ethanol and isopropanol.

4. The lead halide hybrid perovskite solar cell of claim 1, wherein: The substrate layer is glass, quartz, flexible polyethylene terephthalate or flexible polyethylene naphthalate.

5. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The transparent conductive metal oxide layer is fluorine-doped tin oxide or indium-doped tin oxide.

6. The lead halide hybrid perovskite solar cell of claim 1, wherein: The electron transport layer is tin oxide, titanium oxide or zinc oxide.

7. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The perovskite layer is Cs x (FA 1-y MA y ) 1-x Pb(I z Br 1-z )3, wherein 0 ≤ x≤ 1, 0 ≤ y≤ 1, 0 ≤ z≤ 1.

8. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The hole transport layer is 2,2 ′ ,7,7 ′ -tetra[N,N-di(4-methoxyphenyl)amino]-9,9 ′ -spirobifluorene.

9. The lead halide hybrid perovskite solar cell according to claim 1, characterized in that: The metal electrode layer is a gold electrode or a silver electrode.

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