High-efficiency MA1−z FA z Pbl3−x Cl x perovskite solar cells via mixed A-site cations in the lattice

Abstract

Abstract Inorganic–organic perovskite materials show enormous potential in the aspect of high power conversion efficiency (PCE) due to their superior optoelectronic properties. Herein, we performed a comprehensive analysis of the formamidinium (FA+) influences on the electrical properties and surface morphology of MA1−z FA z Pbl3−x Cl x films, as well as the changes in the perovskite solar cell (PSC) parameter. By adding a suitable amount of FAI to the precursor, a series of PSCs were prepared, with the absorption layer owning a mixed organic cation (MA1−z FA z PbI3−x Cl x ) to passivate interfacial defects and improve stability. This work discovered that the appropriate amounts of FA+ can improve grain size and interference defects generation through interionic interaction. Meanwhile, both the filling factor and the short-circuit current density (J sc) have been enhanced effectively, and the PCE of the champion device is 17.31%. Additionally, the stability of the MA0.6FA0.4PbI3−x Cl x -based PSC is also satisfactory. Under 150 h of darkness at 25 humidity and 25 °C, the PCE fell by just 2.9%. This work reveals that modest FA+ can significantly enhance the film-forming and device performance of MAPbI3−x Cl x by substituting for the A-site cation.