(C6H5C2H4NH3)2FAn-1PbnI3n+1: A quasi two-dimensional perovskite with high performance produced via two-step solution method

At present, perovskite solar cells using two-dimensional perovskite hybrids have been researching, for their good optical performance and humidity stability work. However, there is still a great obstacle obtaining two-dimensional perovskite films of high quality and high performances. In this work, we succeeded in fabricating dense and highly crystallized Q-2D (C 6 H 5 C 2 H 4 NH 3 ) 2 FA n-1 Pb n I 3n+1 by adopting a novel two-step solution deposition method, from which a stoichiometric precursor containing PEAI and PbI 2 was first spin-coated and FAI solution was then dropped and spin-coated on the substrate. It was found that the amount of FAI solution dropped onto the substrate during the second step had great influence on the microstructure and performance of the Q-2D (C 6 H 5 C 2 H 4 NH 3 ) 2 FA n-1 Pb n I 3n+1 . Our first–generation Q-2D (C 6 H 5 C 2 H 4 NH 3 ) 2 FA n-1 Pb n I 3n+1 perovskite solar cells were higher than its 3D perovskite counterpart FAPbI 3 in moisture stability. We finally obtained Q-2D (C 6 H 5 C 2 H 4 NH 3 ) 2 FA n-1 Pb n I 3n+1 perovskite solar cells, showing an open-circuit voltage of 0.826 V and a power conversion efficiency of 11.46%.