Surface passivation boosted performances of perovskite solar cells assembled under ambient conditions

Boosted performances were measured for perovskite solar cells (PSCs) through interface engineering via surface passivation using p-toluenesulfonamide (PTSA) between the CH3NH3PbI3 (MAPbI(3)) and CuInS2 (CIS) hole transporting layer (HTL) films in ambient environment. All PSCs were assembled with an inexpensive archi-tecture: FTO/block-TiO2 (b-TiO2)/mesoporous TiO2 (m-TiO2)/MAPbI(3)/CIS/carbon. Furthermore, to explore PTSA-x-y effects onto the PSCs performances, the PTSA concentration (x) and layer number (y) were varied. For this purpose, two PTSA concentrations of 50 and 100 mg/mL along with up to four layer numbers were spin -coated over the MAPbI(3) film. The optimum PTSA concentration was found to be PTSA-50-2 indicating two layers of 50 mg/mL were coated on the perovskite layer. The SEM images exhibited that the PTSA-50-2 and PTSA-100-1 films had homogeneous surfaces without any pin-holes or tracks which were highly desirable to achieve high efficiency. The champion PSC contained the PTSA-50-2 interface layer which displayed the utmost power conversion efficiency (PCE) of 11.24% (J(SC) = 21.32 mA cm(-2), V-OC = 913.96 mV, FF = 0.58) demon-strating 64% PCE enhancement in comparison to that of champion reference cell assembled without PTSA film (PCE = 6.85%). Hence, surface passivation of the MAPbI(3) perovskite by the PTSA was an appropriate approach to fabricate large scale and cost-effective PSCs.