Acta Phys. -Chim. Sin. ›› 2025, Vol. 41 ›› Issue (3): 100029.doi: 10.3866/PKU.WHXB202407025

Special Issue: Next-Generation Optoelectronic Functional Materials

• ARTICLE • Previous Articles    

NbSe2 Nanosheets Improved the Buried Interface for Perovskite Solar Cells

Pengyu Dong1, Yue Jiang1,*(), Zhengchi Yang1, Licheng Liu1, Gu Li1, Xinyang Wen1, Zhen Wang1,*(), Xinbo Shi2, Guofu Zhou3, Jun-Ming Liu4, Jinwei Gao5,1,*()   

  1. 1 Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
    2 Chain Walking New Material Technology (Guangzhou) Co. LTD., Guangzhou 511462, China
    3 Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
    4 Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
    5 Centre for Advanced Optoelectronics, School of Physics and Electronic Information, Gannan Normal University, Ganzhou 341000, Jiangxi Province, China
  • Received:2024-07-26 Revised:2024-08-21 Accepted:2024-08-30 Published:2024-12-14
  • Contact: Email: yuejiang@m.scnu.edu.cn (Yue Jiang)zhenwang@m.scnu.edu.cn (Zhen Wang)gaojinwei@m.scnu.edu.cn (Jinwei Gao)
  • Supported by:
    National Natural Science Foundation of China(52472193); National Natural Science Foundation of China(62105124); the Guangdong Basic and Applied Basic Research Foundation(2022A1515010264); the Guangdong Basic and Applied Basic Research Foundation(2022B1515120006); the Science and Technology Programs of Guangzhou(202201000008); the China Postdoctoral Science Foundation(2022M721215)

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Abstract:

Organic-inorganic metal halide perovskite solar cells (PSCs) are favorable candidates for next-generation solar cells, due to their excellent photovoltaic performance and promising low-cost fabrication process. Particularly, tin oxide (SnO2), with excellent charge mobility and extraction efficiency, is widely used as electron transport layers (ETLs), and the efficiency of the corresponding n-i-p-type perovskites has been certified as high as 26.21% in single-junction devices. The SnO2 layer serves as the substrate for the growth of perovskite films, determining the crystalline quality and the buried interface of perovskite films. However, due to the different thermal expansion coefficient of SnO2 and perovskite, the subsequent perovskite annealing process leads to the residual stress at the buried interfaces and lattice distortion in the perovskite films, which seriously affects their optoelectronic performance and stability. To release this interfacial stress, researchers have made some progress by applying different polymers and small molecules to the SnO2/perovskite interface as a buffer layer. Among these, two-dimensional (2D) nanosheets with high carrier mobility, a wide bandgap range, and excellent optical absorption properties are promising, especially 2D NbSe2 nanosheets showing the advantages of solution-processability, high intrinsic conductivity and clean smooth surface, namely without dangling bonded atoms. Herein, 2D NbSe2 nanosheets have been introduced at the SnO2/perovskite interface to release the undesired residual tensile strain in perovskite films and to form a more matched interfacial energy level alignment. As a result, we have obtained a high-quality perovskite film and further an improved photovoltaic performance. The PCE has been increased from 21.81% to 24.05%. The unencapsulated cell maintained 91% of the initial efficiency after aging over 1000 h under atmospheric condition.

Key words: Perovskite solar cells, Two-dimensional material, Strain relief, Cascade energy alignment