The improvement in organic photovoltaic response by inserting an interlayer between MoO3 and mixed layer of C60:5 wt% TAPC

Abstract

We demonstrate organic photovoltaic (OPV) cells with structure of ITO/MoO3 (5nm)/boron subphthalocyanine chloride (SubPc) (d nm)/C60:5wt% 1,1-bis-(4-methyl-phenyl)-aminophenyl-cyclohexane (TAPC) (40nm)/BCP (8nm)/Al, where d=0, 1, 3, 5, 7 and 13nm. We found that a 5-nm-thick SubPc based cell had a peak power conversion efficiency (PCE) of 3.75% and a voltage (Voc) of 1.03V, which was an increase of 35.4% and 0.19V, respectively, compared with the reference cell without SubPc. We found that the spectral response of cells with 1–5nm SubPc mostly corresponded to the C60 absorption and the cell with 5nm SubPc had the highest responsivity. The spectral response of the cell with 13nm SubPc corresponded to both C60 and SubPc absorptions, which is analogous to a previously reported flat heterojunction cell. The excellent PV parameter of the cell with 5nm SubPc was attributed to a built-in field induced by the Schottky barrier contact of MoO3/5-nm SubPc. To confirm this hypothesis, another two series of OPV cells with different interlayers and donors instead of SubPc and TAPC were developed.