Numerical Simulation to Achieve High Efficiency in CuTlSe2–Based Photosensor and Solar Cell

Abstract

This article presents the design and numerical investigation of a novel dual-function architecture that integrates a photosensor (PS) and a solar cell (SC), based on the chalcogenide compound copper thallium selenide (CuTlSe2), utilizing cadmium sulfide (CdS) as the window layer and germanium sulfide (GeS) as the back surface field (BSF) layer. Simulations have been conducted using SCAPS-1D software, utilizing material parameters obtained from the literature and previously reported experimental studies. The optimized device, with the GeS BSF layer, achieves a power conversion efficiency (PCE) of 31%, an open-circuit voltage (VOC) of 0.84 V, a short-circuit current density (JSC) of 43.18 mA cm−2, and a fill factor (FF) of 85.88%. In contrast, without the BSF layer, the device delivers a reduced PCE of 22.97%, JSC of 38.64 mA cm−2, VOC of 0.73 V, and FF of 81%. Additionally, the proposed structure reveals superior photosensing performance, achieving a peak responsivity (R) of 0.78 A W−1 and detectivity (D∗) of 2 × 1015 Jones at a photon wavelength of 1040 nm in the presence of the BSF layer. The device exhibits enhanced spectral response in the near-infrared (NIR) region, specifically within the wavelength range of 800–1100 nm, emphasizing its proficiency in NIR light detection. These findings highlight the potential of CuTlSe2–based structures for efficient dual-function photovoltaic (PV) and photosensing applications.