The Brownian Ratchet Effect for Driving Carriers to Directional Transport in Organic Photovoltaic Devices

At the microscopic quantum level, we proposed a Brownian ratchet mechanism at the nanoscale within organic photovoltaic devices (OPVs). By considering the cooperation of the asymmetric potential and thermal noise, it is found that a directional photocurrent appears, even in the absence of a net driving field. This mechanism is unique for OPVs due to the quasi-particle characteristic of the photogenerated polarons. This work opens a promising perspective for improving directional charge transport, thereby enhancing the performance of OPVs.