Simple planar perovskite solar cells with a dopant-free benzodithiophene conjugated polymer as hole transporting material

Abstract

Dopant-free poly[(4,8-bis-(2-ethylhexyloxy)-benzo[1,2-b;4,5-b′]dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b] thiophene)-2,6-diyl] (PBDTTT-C) polymer is used as hole transporting material (HTM) in electron transporting material (ETM) free planar perovskite solar cells (PSCs). The devices with a PBDTTT-C HTM show higher power conversion efficiency (PCE = 9.95%) than the devices with a P3HT HTM (PCE = 6.17%) with enhanced short circuit current density (J_sc), open circuit voltage (V_oc) and fill factor (FF) in a simple device configuration (ITO/CH₃NH₃PbI₃/PBDTTT-C/MoO₃/Ag), due to the suitable energy level, better carrier mobility and lower interfacial charge recombination.