Favorable growth of well-crystallized layered hybrid perovskite by combination of thermal and solvent assistance

Abstract

In recent years, attention is increasingly paid to developing layered two-dimensional perovskites due to their superior environmental stability compare with their three-dimensional analogues. However, two-dimensional perovskite based solar cells usually give unsatisfactory photovoltaic performance due to large numbers of defects in the process of crystallinity. Many groups investigate multiple approaches to improve the crystalline quality so far. Here, we systematically investigate the influence of temperature on two-dimensional (PEA)2(MA)2Pb3I10 perovskite films crystallinity based on hot-casting and post-annealing. The crystallization of (PEA)2(MA)2Pb3I10 in the case of hot-casting has better crystallinity than post-annealing and discover the thermal annealing and solvent-assisted mass transfer are very important in the process of crystallization based on two-dimensional perovskite. As a result, the devices obtain a highest power conversion efficiency of 5.57% at 100 °C (hot-casting) by optimizing heating temperature of the substrate and the hot-casting two-dimensional (PEA)2(MA)2Pb3I10 films and devices display superior ambient stability. This work provides an important reference for further improve the crystallization of two-dimensional perovskite film.