Liu Minchao, Zhang Jinyuan, Qin Shucheng, Miao Xiaodan, Yuan Meng, Liu Zhe, Wang Yiyang, Feng Yishun, Jiang Xin, Wu Ruihan, Yi Yuanping, Meng Lei, Li Yongfang
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
School of Chemical Science, University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2024 Nov 20;146(46):32105-32116. doi: 10.1021/jacs.4c13248. Epub 2024 Nov 8.
Chemical additives play a critical role in the crystallization kinetics and film morphology of perovskite solar cells (pero-SCs), thus affecting the device performance and stability. Especially, carboxylic acids and their congeners with a -COOH group can effectively serve as ligands to fortify the structural integrity and mitigate the risk of lead efflux. However, direct addition of -COOH into the precursor solution could retard the crystallization kinetics of the perovskite during film formation due to the strong coordination. Here, we present a novel approach of in situ functional group conversion using Bis(2,5-dioxopyrrolidin-1-yl) 4,7,10,13-tetraoxahexadecanedioate (Bis-PEG4-NHS ester) as an additive in the antisolvent, which underwent a functional group transformation from -COOR to -COOH during the annealing process through a hydrolysis reaction of Bis-PEG4-NHS ester. The corresponding hydrolysates exhibit enhanced interactions with PbI and FAI, contributing to the structural integrity and the defect passivation. Our findings offer valuable insights into the chemical interactions within the crystal growth process, achieving the p-i-n pero-SC device with an efficiency of 25.79% (certified as 25.47%) and notable long-term stability.
化学添加剂在钙钛矿太阳能电池（pero-SC）的结晶动力学和薄膜形态中起着关键作用，从而影响器件性能和稳定性。特别是，带有-COOH基团的羧酸及其同系物可以有效地作为配体，增强结构完整性并降低铅泄漏的风险。然而，由于强配位作用，将-COOH直接添加到前驱体溶液中可能会在成膜过程中阻碍钙钛矿的结晶动力学。在此，我们提出了一种新颖的原位官能团转化方法，使用双（2,5-二氧代吡咯烷-1-基）4,7,10,13-四氧杂十六烷二酸酯（双-PEG4-NHS酯）作为反溶剂中的添加剂，其在退火过程中通过双-PEG4-NHS酯的水解反应经历了从-COOR到-COOH的官能团转变。相应的水解产物与PbI和FAI表现出增强的相互作用，有助于结构完整性和缺陷钝化。我们的研究结果为晶体生长过程中的化学相互作用提供了有价值的见解，实现了效率为25.79%（认证为25.47%）且具有显著长期稳定性的p-i-n钙钛矿太阳能电池器件。
