Simple planar heterojunction fullerene-free organic photovoltaic cell with high open-circuit voltages above 1.4 V

Abstract

In this work, we describe the performance of organic photovoltaic cells (OPVs) based on the electron donor–acceptor pairing of rubrene and boron subphthalocyanine chloride (SubPc). An open-circuit voltage as high as 1.4 V is obtained, which is resulted from large difference between the highest occupied molecular orbital of the electron donor rubrene and the lowest unoccopied molecular orbital of the electron acceptor SubPc. Device performance shows a strong dependence on the thickness of rubrene as donor, and peak power conversion efficiency is achieved at a thickness of rubrene as thin as 5 nm. The optimized OPVs realize a power conversion efficiency of 2.4% under a simulated AM1.5 G solar illumination at 100 mW/cm2. A better stability of the cells with SubPc as acceptor is also achieved.