Excitonic solar cells based on van der Waals heterojunctions of Janus III–VI chalcogenide monolayers

Abstract

Abstract We construct the two-dimensional (2D) excitonic solar cells based on type II vdW heterojunctions of Janus III–VI chalcogenide monolayers and investigate the performance of the device using the first principle. The calculated solar energy absorbance of In2SSe/GaInSe2 and In2SeTe/GaInSe2 heterojunctions is the order of 105 cm−1. The predicted photoelectric conversion efficiency of the In2SeTe/GaInSe2 heterojunction can reach up to 24.5%, which compares favorably with other previously studied 2D heterojunctions. The excellent performance of In2SeTe/GaInSe2 heterojunction originates from the fact that the built-in electric field at the interface of In2SeTe/GaInSe2 promote the flow of the photogenerated electrons. The results suggest that 2D Janus Group-III chalcogenide heterojunction can be a good candidate for new optoelectronic nanodevices.