Additive Molecules Adsorbed on Monolayer PbI 2 : Atomic Mechanism of Solvent Engineering for Perovskite Solar Cells

作者：Hongfei Chen, Qiye Guan, Hejin Yan, Xiangyue Cui, Zheng Shu, Yongqing Cai · 发表于：ACS Applied Materials & Interfaces · 年份：2023 · DOI：10.1021/acsami.3c05933 · 被引用次数：24 · 研究领域：Perovskite Materials and Applications、Quantum Dots Synthesis And Properties、Advanced Thermoelectric Materials and Devices

Solvent engineering is highly essential for the upscaling synthesis of high-quality metal halide perovskite materials for solar cells. The complexity in the colloidal containing various residual species poses great difficulty in the design of the formula of the solvent. Knowledge of the energetics of the solvent-lead iodide (PbI 2 ) adduct allows a quantitative evaluation of the coordination ability of the solvent. Herein, first-principles calculations are performed to explore the interaction of various organic solvents (Fa, AC, DMSO, DMF, GBL, THTO, NMP, and DPSO) with PbI 2 . Our study establishes the energetics hierarchy with an order of interaction as DPSO > THTO > NMP > DMSO > DMF > GBL. Different from the common notion of forming intimate solvent–Pb bonds, our calculations reveal that DMF and GBL cannot form direct solvent–Pb 2+ bonding. Other solvent bases, such as DMSO, THTO, NMP, and DPSO, form direct solvent–Pb bonds, which penetrate through the top iodine plane and possess much stronger adsorption than DMF and GBL. A strong solvent–PbI 2 adhesion (i.e., DPSO, NMP, and DMSO), associated with a high coordinating ability, explains low volatility, retarded precipitation of the perovskite solute, and tendency of a large grain size in the experiment. In contrast, weakly coupled solvent–PbI 2 adducts (i.e., DMF) induces a fast evaporation of the solvent, accordingly a high nucleation density and small grains of perovskites are observed. For the first time, we reveal the p...