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/MoO 3 (5 nm)/boron subphthalocyanine chloride (SubPc) ( d nm)/C 60 :5 wt% 1,1-bis-(4-methyl-phenyl)-aminophenyl-cyclohexane (TAPC) (40 nm)/BCP (8 nm)/Al, where d  = 0, 1, 3, 5, 7 and 13 nm. 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 1.03 V, which was an increase of 35.4% and 0.19 V, respectively, compared with the reference cell without SubPc. We found that the spectral response of cells with 1–5 nm SubPc mostly corresponded to the C 60 absorption and the cell with 5 nm SubPc had the highest responsivity. The spectral response of the cell with 13 nm SubPc corresponded to both C 60 and SubPc absorptions, which is analogous to a previously reported flat heterojunction cell. The excellent PV parameter of the cell with 5 nm SubPc was attributed to a built-in field induced by the Schottky barrier contact of MoO 3 /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.