Degradation of electrical properties of small molecule organic solar cells under oxygen and moisture

Abstract

ABSTRACTWe investigated the photovoltaic (PV) parameters of a planar hetero-junction solar cell with di-[4-(N,Nditolyl-amino)-phenyl] cyclohexane (TAPC) as donor (D) and C60 as acceptor (A), upon exposing the acceptor side to oxygen and moisture. We found that for the same time of exposure, even minor oxygen amounts lead to more detrimental results compared to moisture. We argue that the photo-conversion efficiency (PCE) decreases due to creation of recombination centers at the interface, which induce losses in exciton diffusion and charge generation. Under the same conditions, we also registered a direct connection between the cell PV parameters’ decay and a C60 thin-film conductivity loss.