Computational investigation on the photovoltaic performance of an efficient GeSe-based dual-heterojunction thin film solar cell

This article reports the design and computational analysis of an efficient GeSe-based n-ZnSe/p-GeSe/p+-WSe2 dual-heterojunction (DH) thin film solar cell using SCAPS-1D simulation program with physical parameters from the literature. The device has been optimized considering the thickness, doping and defect density of each layer. The optimized device shows an efficiency of ∼42.18% with a short circuit current density, JSC of 47.84 mA cm−2, an open circuit voltage, VOC of 1.07 V and fill factor, FF of 82.80%, respectively that remains within the Shockley-Queisser limit of a DH solar cell. The raised built-in potential developed between the two interfaces of the devices produces a surpassing VOC. The higher JSC is attributed to the current generated by absorption of sub-band gap photons by a tail-states-assisted two-step photon upconversion mechanism in the WSe2 back surface field layer. These results indicate the potential of manufacturing the high efficiency GeSe-based DH solar cell in future.