Ma Yue, Cai Haoyu, Liu Yongjun, He Biqi, Zhang Hongfei, Cheng Yaqi, Liu Guodong, Zhao Juan, Cheng Yi-Bing, Zhong Jie
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P.R. China.
School of Automobile Engineering, Wuhan University of Technology, Wuhan, 430070, P.R. China.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202504253. doi: 10.1002/anie.202504253. Epub 2025 Jun 3.
The precursor quality critically determines the morphology, grain size, crystallinity, and trap state density of the perovskite films. A long shelf life of the perovskite precursor could greatly benefit the reliable upscaling of perovskite solar cells (PSCs). Herein, we suggest that the most commonly used N, N-Dimethylformamide/Dimethyl sulfoxide (DMF/DMSO) mixed solvent exhibits more severe degradation compared to its corresponding single solvents, due to the complex interplay of reactions, including hydrolysis, oxidation, and deprotonation of precursor species in the solution. 2-thiouracil (Th) was thus introduced into the precursor to inhibit these side reaction chains and effectively alleviate the detrimental degradation of cations and iodide ions (I⁻). The synergistic effects of Th allow it to bind with undercoordinated Pb, modulating the crystallization process and thereby achieving high-quality films with a low defect density. Consequently, Th-based precursor demonstrates enhanced shelf life, retaining 94.78% of the initial efficiency (25.13%) of the device prepared from fresh solution after 30 days of aging, compared to 64.22% for the control sample. The target device also exhibits remarkable stability, maintaining 87.8% of its initial efficiency after 1000 h of maximum power point tracking.
前驱体的质量对钙钛矿薄膜的形貌、晶粒尺寸、结晶度和陷阱态密度起着关键决定作用。钙钛矿前驱体的长保质期对钙钛矿太阳能电池（PSC）的可靠扩大规模将大有裨益。在此，我们表明，由于溶液中前驱体物种的水解、氧化和去质子化等反应的复杂相互作用，最常用的N，N-二甲基甲酰胺/二甲基亚砜（DMF/DMSO）混合溶剂与其相应的单一溶剂相比，表现出更严重的降解。因此，将2-硫脲（Th）引入前驱体中，以抑制这些副反应链，并有效减轻阳离子和碘离子（I⁻）的有害降解。Th的协同作用使其能够与配位不足的Pb结合，调节结晶过程，从而获得具有低缺陷密度的高质量薄膜。因此，基于Th的前驱体显示出延长的保质期，在老化30天后，由新鲜溶液制备的器件保留了初始效率（25.13%）的94.78%，而对照样品为64.22%。目标器件还表现出显著的稳定性，在最大功率点跟踪1000小时后保持其初始效率的87.8%。
