Lead-Free CH 3 NH 3 SnBr 3 Photodetector with Low Dark Current Enabling Sensitive Low-Intensity Light Detection

This study presents a numerical simulation of the performance of perovskite-based photodetectors (PDs) with the tin-based absorptive material CH 3 NH 3 SnBr 3 , using SCAPS-1D. A device was designed on the architecture, using fluorine-doped tin oxide (FTO) as the front contact, PCBM as the electron transport layer (ETL), P3HT as the hole transport layer (HTL), and gold as the back contact. The parameters that affect key performance, such as responsivity, detectivity, dark current, quantum efficiency, thermal stability, and absorber thickness, were analyzed. The performance of the CH 3 NH 3 SnBr 3 -based PD was found to be very high, with a maximum responsivity of ~0.48 A/W at 650 nm, detectivity of 9.6×10 13 Jones, and quantum efficiency of up to 90%, with a wide spectral range (400-800 nm). It also showed high thermal stability and uniform open-circuit voltage (V OC ) and short-circuit current density (J SC ) over a temperature range of 250 K to 450 K. This high performance of CH 3 NH 3 SnBr 3 is observed due to the optimized energy band alignment and the greater built-in electric field, which improves carrier separation and decreases recombination losses. The findings identify CH 3 NH 3 SnBr 3 as a very promising perovskite-based detector technology on a scalable high-performance platform applicable in optical sensing and environmental conditions.