Cationic Management for Efficient and Stable FAPbI3-Based Perovskite Solar Cells

Abstract

Highly efficient perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) > 25% are fabricated with formamidinium (FA)-based lead triiodide (FAPbI3) perovskites. In general, mixed cations and anions containing FA, methylammonium (MA), Cs, I and Br ions are used to stabilize the black α-phase against d-phase of the pristine FAPbI3. Disadvantageously, the additives such as MA, Cs and Br to FAPbI3 widen its bandgap and reduce the thermal stability due to the lower thermal decomposition of MA to FA. Therefore, in order to further increase PCE through the enhanced photocurrent density due to the increased light harvesting, stabilizing the a-FAPbI3 without blue-shift of the bandgap is needed. In addition, structural dimensions, distortion, and dielectric properties can vary significantly depending on the ionic radius and type of the A-site cation. In this presentation, I would like to introduce the impact of cationic management on the efficiency and long-term stability of perovskite solar cells.