A V-shaped analog of ITIC with a small exciton binding energy

Abstract The exciton binding energy (Eb) of organic semiconductors is a key parameter that determines the performance of organic optoelectronic devices. Here, we focus on ITIC, a representative organic semiconductor used in organic photovoltaics (OPVs), and investigate the influence of molecular structure on Eb by developing io-ITIC, a V-shaped isomer of ITIC. Experimental results reveal that io-ITIC exhibits a small Eb compared to ITIC. However, OPVs based on io-ITIC showed moderate photovoltaic characteristics. Theoretical studies including molecular dynamics simulations indicate that the stacking configuration of io-ITIC affects Eb and OPV characteristics.