Multifunctional Molecule Engineered SnO<sub>2</sub> for Perovskite Solar Cells with High Efficiency and Reduced Lead Leakage
Jiali Zhang, Renjie Li, Sofia Apergi, Pengyang Wang, Biao Shi, Junke Jiang, Ningyu Ren, Wei Han, Qian Huang, Geert Brocks, Ying Zhao, Shuxia Tao, Xiaodan Zhang
Abstract
Outstanding performance of perovskite solar cells (PSCs) is closely linked to the optoelectrical properties of charge transporting layers. Herein, amino trimethylene phosphonic acid (ATMP) and KOH are mixed (ATMP‐K) and incorporated in a SnO 2 precursor solution to significantly improve the performance of the electron transport layer (ETL) SnO 2 in PSCs. Combining density functional theory (DFT) calculations and experiments, it is demonstrated that ATMP‐K effectively passivates the oxygen vacancy and reduces the hydroxyl groups on the surface of SnO 2 , resulting in a larger perovskite grain size and better energy‐level alignment with perovskites. ATMP‐K boosts the power conversion efficiency (PCE) of the PSCs from 20.99% to 23.52%. When applying in a perovskite/silicon heterojunction tandem solar cell, the device delivers an efficiency up to 24.75% with a high V OC of 1.94 V, compared with 22.67% and 1.85 V of the reference cells. Furthermore, ATMP‐K‐modified PSCs also show extraordinary ability to absorb Pb 2+ ions after their degradation in water, offering a facile strategy for reducing Pb leakage.