All-polymer indoor photovoltaics with high open-circuit voltage

Abstract

Indoor photovoltaic (IPV) cells receive increasing attention because of their promising applications as power sources for devices of the Internet of Things ecosystem. Under indoor artificial light illumination with narrow emission spectra, short-circuit current density is limited, and thus the IPV efficiency is highly dependent on open-circuit voltage (V_OC). However, the V_OC of various IPV cells, including silicon, III–V semiconductor, dye-sensitized, organic/polymeric, and perovskite photovoltaic cells, is mainly lower than 1 V due to their small optical bandgaps. Here, we report the first all-polymer IPVs using a blend of polymer donor and polymer acceptor as the active layer. Owing to the medium bandgap (E_g = 1.93 eV) and proper energy level alignment of the two polymers, the all-polymer IPV cell shows a high power conversion efficiency of 27.4% with an unprecedentedly high V_OC of 1.16 V under fluorescent lamp illumination. This work opens up a research field of all-polymer photovoltaics for indoor light-harvesting applications.