Design and Performance Assessment of Cs ₂ CuSbCl ₆ ‐Based Double‐Perovskite Photodetector Using Integrated DFT and SCAPS‐1D Simulations

We present the design of a Cs 2 CuSbCl 6 ‐based double‐perovskite photodetector for visible‐range detection. Initially, we evaluated the structural, electronic, and optical properties of Cs 2 CuSbCl 6 using first‐principles DFT calculations. The DFT results indicate the potential of Cs 2 CuSbCl 6 as a light‐absorbing semiconductor with an indirect bandgap of 1.74 eV. Finally, we evaluated Cs 2 CuSbCl 6 ‐based photodetector devices using SCAPS‐1D with various charge‐transport layers (CTLs) (TiO 2 , ZnO, WS 2 , SnO 2 , CdS, CuI, Cu 2 O, CuSbS 2 , Spiro‐OMeTAD, NiO). Device performance is also evaluated by varying the thickness, defects, and doping concentration of the absorber and CTLs. Additionally, the effects of the metal work function and the series and shunt resistances are evaluated. The photodetectors with the configuration FTO/WS 2 /Cs 2 CuSbCl 6 /Cu 2 O/Pt demonstrated a maximum J SC of ∼19.98 mA/cm 2 . The photodetector exhibits a maximum responsivity of 0.45 AW −1 and a detectivity of 4.02 × 10 11 Jones near 600 nm. This study presents Cs 2 CuSbCl 6 as a stable, lead‐free perovskite for high‐performance visible photodetectors.