Precursor engineering for efficient and stable perovskite solar cells

Fuyuan Luan; Haiyan Li; Shuiping Gong; Xinyu Chen; Chunhui Shou; Zihua Wu; Huaqing Xie; Songwang Yang

doi:10.1088/1361-6528/ac9f4f

Precursor engineering for efficient and stable perovskite solar cells

Nanotechnology. 2022 Nov 18;34(5). doi: 10.1088/1361-6528/ac9f4f.

Authors

Fuyuan Luan^{1

2

3}, Haiyan Li², Shuiping Gong², Xinyu Chen², Chunhui Shou⁴, Zihua Wu^{1

3}, Huaqing Xie^{1

3}, Songwang Yang^{1

2

5}

Affiliations

¹ School of Energy and Materials, Shanghai Polytechnic University, Shanghai 201209, People's Republic of China.
² CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Shanghai 201899, People's Republic of China.
³ Shanghai Engineering Research Center of Advanced Thermal Functional Materials, Shanghai 201209, People's Republic of China.
⁴ Key Laboratory of Solar Energy Utilization & Energy Saving Technology of Zhejiang Province, Zhejiang Energy Group R&D, Hangzhou, Zhejiang 310003, People's Republic of China.
⁵ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.

PMID: 36322962
DOI: 10.1088/1361-6528/ac9f4f

Abstract

The perovskite film prepared by the two-step spin coating method is widely used in photovoltaic devices due to its good film morphology and great reproducibility. However, there usually exists excessive lead iodide (PbI₂) in the perovskite film for this method, which is believed to passivate the grain boundaries (GBs) to increase the efficiency of the perovskite solar cells. Nevertheless, the excessive PbI₂at the GBs of perovskite is believed to induce the decomposition of the perovskite film and undermine the long-term stability of devices. In this study, we utilize precursor engineering to realize the preparation of perovskite solar cells with high efficiency and stability. The concentration of organic salts (AX: A = MA⁺, FA⁺; X = I^-, Cl^-) in the precursor solution for the second step of the two-step spin coating method is adjusted to optimize the perovskite light-absorbing layer so that the excessive PbI₂is converted into perovskite to obtain a smooth and pinhole-free perovskite film with high performance. Our results indicate that by adjusting the concentration of AX in the precursor solution, PbI₂in the film could be completely converted into perovskite without excessive AX residue. Both the efficiency and stability of the perovskite solar cells without excessive PbI₂have been significantly improved. A planar perovskite solar cell with the highest power conversion efficiency (PCE) of 21.26% was achieved, maintaining about 90% of the initial PCE after 300 h of storage in a dry air environment and in the dark, about 76% of the initial PCE after 300 h of continuous illumination of 1 Sun.

Keywords: concentration; lead iodide; perovskite solar cell; stability; suppression.