Reinforcing perovskite framework via aminotrifluorotoluene for achieving efficient and moisture-resistance solar cells

Perovskite solar cells (PSCs) are one of the most prospective photovoltaic devices because of their excellent photoelectric properties, yet their stability remains challenging. Apart from the reported passivation or encapsulation strategies, reinforcing the inherent framework of the perovskite is recognized as a substantial approach to stabilizing the PSCs. Herein, a multifunctional 2-amino-acetamidobenzotrifluoride (called BDP) with –NH2, C = O, and -CF3 moieties is meticulously screened to strengthen the perovskite framework. The electron-donating groups of the BDP (–NH2 and C = O) can simultaneously modify the crystallization process and achieve passivation, which devoted to reducing defect density; -CF3 is used as a hydrophobic chemical stabilizer to form a moisture-resistant layer on the perovskite surface and suppress the MA+ ion migration by forming a hydrogen bond. Notably, the presence of the BDP also achieves a better energy level matching at the perovskite/hole transfer layer interface. Consequently, the power conversion efficiency (PCE) of MAPbI3 solar cells is remarkably improved from 18.47% to 21.62%. Compared with the control devices, the PCE remains relatively stable under harsh external environmental conditions. Furthermore, the BDP also inhibits the lead leakage of PSCs, which is conducive to environmental applications.