A wearable organic photovoltaic-thermoelectric (OPV-TE) hybrid generator to minimize the open-circuit voltage losses of OPV module

Abstract

This work presents a hybrid generator, composed of an organic photovoltaic (OPV) module and a thermoelectric generator (TEG), to improve power generation performance mainly by minimizing the open-circuit voltage (VOC) losses of OPV modules. Thanks to the TEG, which utilizes heat energy, the proposed device can be used to harvest electrical energy even after the sun goes down. After hybridization, the external quantum efficiency and photon absorption of the OPV module increased remarkably, especially in the long wavelength region. The VOC of the hybrid generator increased more than the arithmetic sum of the VOCs of the TEG and OPV module, thanks to the reduction in nonradiative recombination. The hybrid generator also had a longer charge recombination lifetime, despite the much larger number of excess charge carriers compared to the OPV module alone. This allows the hybrid generator to have a higher short-circuit current than the OPV module alone has. As a result, the hybrid generator can harvest up to 46.3% more electrical energy than an OPV module alone throughout the day. Wearing the wearable hybrid generator on the forearm for 30 min outdoors could harvest up to 34 mWh during the day, and up to 5.9 mWh at night.