Highly efficient organic photovoltaic cells fabricated by electrospray deposition using a non-halogenated solution

Since a large amount of solvents are needed for roll-to-roll printing processes of organic photovoltaic cells, an environmentally friendly process for practical mass production systems is in high demand. In this research, a highly efficient organic photovoltaic cell was successfully demonstrated by the electrospray deposition method using a non-halogenated solvent, o-xylene. An addition of acetonitrile and 1,8-diiodooctane drastically reduced domain size of the organic active layer, resulting in improved device performance. In addition, the photoconversion efficiency was continuously increased with increasing the solvent evaporation time of a droplet deposited on a substrate, and the highest photoconversion efficiency of 5.6% was achieved by optimizing the solvent evaporation time. Current-density-voltage characteristics under irradiation with AM 1.5 light and corresponding AFM images of the active layers electrosprayed with and without the addition of 1,8-diiodooctane in o-xylene and acetonitrile.