A novel interface layer for inverted perovskite solar cells fabricated in ambient air under high humidity conditions

Abstract

A novel benzotriazol based small molecule (2-hexyl-4,7-bis(5'-hexyl-2,2'-bithien-5-yl)-2H-1,2,3-benzotriazole) BTBT was synthesized by Suzuki coupling reaction and was successfully employed in planar inverted perovskite solar cells with ITO/BTBT/PEDOT:PSS/CH3NH3PbI3-xCl(x)/PCBM/Al configuration. Fabrication processes, including the spin coating of the perovskite layer, were performed in ambient air, under high humidity conditions (>60%). BTBT/PEDOT:PSS bilayer notably improved the power conversion efficiencies (PCE) from 9.65% to 11.6%, which corresponds to an increase of 20%.