Lead-free organic-inorganic tin halide perovskites were prepared and investigated by a rapid screening technique utilizing a modified scanning electrochemical microscope (SECM). We studied liquid junction photoelectrochemical (PEC) solar cells based on p-type methylammonium tin halide (MASnI(3-x),Br-x) perovskites employing the benzoquinone (BQ) redox couple, BQ/BQ(center dot-), in dichloromethane (CH2Cl2). We found that the optimized Sn-based mixed halide perovskite, MASnI(0.5)Br(2.5), exhibits enhanced performance and stability in liquid junction PEC solar cells, with a power conversion efficiency of 1.51% (an increase of 20.8%) and a photovoltaic lifetime of 175 min (an increase of 75.0%), in comparison to MASnI(3) perovskites. (C) 2016 Elsevier Ltd. All rights reserved.