LAUSR

Abstract Hole-conductor-free perovskite solar cells (PSCs) were fabricated using carbon as counter electrodes (CE) and TiO 2 nanosheet (NS) layers as photoanode. The effect of TiO 2 NS layer thickness on the performance and charge carrier recombination of PSCs was investigated and discussed. With increasing the thickness of TiO 2 NS layer, more CH 3 NH 3 PbI 3 was adsorbed into the TiO 2 NS photoanode and the interfacial recombination of electrons and holes at TiO 2 NS/perovskite interface was reduced, leading to the higher short-circuit current density ( J sc ) and open-circuit voltage ( V oc ). However, over-thick TiO 2 layer not only caused a low fill factor ( FF ) but also decreased the performance of PSCs. The optimized PSC with the thickness of 1.0 μm TiO 2 NS layer obtained J sc of 14.11 mA cm −2 ,  V oc of 0.85 mV, FF of 0.68 and the power conversion efficiency (PCE) of 8.11%. The above results suggested that the thickness of TiO 2 NS layer played an important role in the performance of devices.