High-efficiency organic photovoltaic cells processed using a non-halogen solvent

Abstract

In this paper we describe high-performance PM6:BTP-eC9–based organic photovoltaic (OPV) cells prepared using non-halogen solvents, with the goal of minimizing any potential environmental pollution. We investigated three green solvents (toluene, o-xylene, and 1,2,4-trimethylbenzene) as replacements for the commonly used chloroform. Using UV–Vis spectroscopy, atomic force microscopy, two-dimensional grazing incidence wide-angle X-ray spectroscopy, and carrier transport analysis, we optimized the blend films and investigated their optoelectronic properties and those of their respective devices. Among our tested devices, the OPV cell prepared with toluene as the solvent and 1,8-diiodooctane (DIO) as the additive displayed the best performance, with a power conversion efficiency (15.8 ± 0.20%) comparable with that of the chloroform-derived OPV (16.2 ± 0.1%). Thus, it is feasible to replace halogen solvents with non-halogen solvents when preparing OPV devices.