Preparing high-quality perovskite films is crucial to improve the power conversion efficiency (PCE ) of perovskite solar cells (PSCs ), which can be achieved by delaying the crystallization of perovskite films.
Therefore, Liu Shengzhong and others from Shaanxi Normal University designed difluoroacetic anhydride (DFA) as an additive to regulate the crystallization process, thereby reducing the formation of defects during the formation of perovskite films. The study found that DFA reacts with DMSO to form two molecules: difluoroacetate thioether ester (DTE) and difluoroacetic acid (DA ). Strongly bonded DTE·PbI2 and DA·PbI2 delay the perovskite crystallization process to form high-quality films, which are monitored by in-situ UV-visible and PL testing.
By using DFA additive, high-quality, low-defect perovskite films were prepared. Finally, a champion PCE of 25.28% was achieved with excellent environmental stability, retaining 95.75% of the initial PCE after 1152 hours at 25°C and 25% RH.
Yang Cao, Nan Yan, Mingzi Wang, Danyang Qi, Jiafan Zhang, Xin Chen, Ru Qin, Fengwei Xiao, Guangtao Zhao, Yucheng Liu, Xuediao Cai, Kui Zhao, Shengzhong (Frank) Liu, Jiangshan Feng, Angew. Chem. Int . Ed. 2024, e202404401.
https://doi.org/10.1002/anie.202404401