Hydrobromic acid assisted crystallization of MAPbI3−xClx for enhanced power conversion efficiency in perovskite solar cells

Abstract

Enhanced performance of perovskite solar cells based on the application of high quality MAPbI_3−xCl_x films developed via a hydrobromic acid assisted fast crystallization process is reported. A current density (J_sc) of 21.71 mA cm⁻², an open circuit voltage (V_oc) of 0.94 V, a fill factor (FF) of 0.77 and a high power conversion efficiency (PCE) of 15.76% were obtained. Noticeably, the hydrobromic acid assisted device exhibited less hysteresis and followed a crystallization route which is several times faster than that of the traditional one-step spin-coating method. The enhancement in device performance is attributed to the increased parallel resistance, lower leakage current, reduced series resistance and stronger crystallization of the MAPbI_3−xCl_x perovskite layer.