Organic-inorganic hybrid perovskite materials have received extensive attention in the photovoltaic field. However, the toxicity of lead-based perovskite has brought certain restrictions to its application. The development of non-toxic or low-toxic non-lead perovskite solar cells is very important. necessary. Among them, tin-based perovskite material has an ideal band gap and high carrier mobility, and is a low-toxic photovoltaic material. At present, the efficiency of non-lead-tin-based perovskite solar cells has reached more than 10%, proving that tin-based perovskite has great potential in photovoltaic applications. However, tin-based perovskite has the shortcomings of easy oxidation and more vacancy defects, and the faster crystallization rate of tin-based perovskite causes more film defects, which limits the further improvement of the efficiency of tin-based perovskite solar cells.

Recently, Professor Xiangyue Meng of the School of Optoelectronics, University of Chinese Academy of Sciences and his collaborators, using tin halide perovskites as the research object, based on the basic kinetic and thermodynamic theories of the perovskite crystallization process, proposed a cluster based on pre-nucleation ( PNCs) new nucleation theory, constructed high-quality tin halide perovskite solar cell devices. By adding additive PDI₂ to the FASnI₃ perovskite precursor solution to adjust the colloidal chemistry of the perovskite precursor solution, stable clusters have been formed in the perovskite precursor solution before nucleation, these pre-nucleated clusters As an intermediate phase, it reduces the energy barrier of nucleation, making the nucleation process of the perovskite film faster and easier, so as to obtain a high-quality tin-based perovskite film with low defect density. The prepared solar cell device has an efficiency of 11.39% and has good light stability.

In this work, through in-depth understanding and precise control of the crystallization process of tin-based perovskite films, a new nucleation theory based on pre-nucleation clusters is proposed, which has significant effects on the crystallinity, morphology and photoelectric properties of FASnI₃ perovskite. Important regulatory role. This non-classical nucleation theory based on pre-nucleated clusters has important implications for the understanding of the crystallization process of perovskite thin film materials.

This result was recently published in Angewandte Chemie International Edition. Professor Xiangyue Meng is the first author and corresponding author of the article.

Paper information:

Crystallization Kinetics Modulation of FASnI₃ Films with Pre-nucleation Clusters for Efficient Lead-free Perovskite Solar Cells

Xiangyue Meng,* Yunfei Li, Yizhi Qu, Haining Chen, Nan Jiang, Minghua Li, Ding-Jiang Xue, Jin-Song Hu,* Hui Huang,* and Shihe Yang*

Angewandte Chemie International Edition

DOI: 10.1002/anie.202012280