Enhanced Performance of Sn-Based Perovskite Photodetectors Through Double-Sided Passivation for Near-Infrared Applications

The development of high-performance Sn-based perovskite photodetectors is presented with double-sided passivation using large alkylammonium interlayers of PEAI and BDAI₂. This dual passivation strategy, applied to the top and bottom of FASnI₃ films, effectively improves film quality by reducing defect density, enhancing carrier mobility, and minimizing non-radiative energy losses at the interfaces. At 720 nm, the photodetectors demonstrate a responsivity of 0.37 A W⁻¹, a detectivity of 6.12 × 10¹³ Jones, and an external quantum efficiency (EQE) of 65.60%, with a rapid response time of 9 µs. Additionally, at 850 nm, the detectivity reaches as high as 3.27 × 10¹³ Jones. Furthermore, the device demonstrated a low 1/f noise of 1.21 × 10⁻¹⁵ AHz⁻⁰.⁵ at 10 Hz. Transient photocurrent (TPC) and transient photovoltage (TPV) measurements revealed a significant increase in charge recombination lifetime (τ_e) and improved charge transfer efficiency. These results showcase the potential of Sn perovskite photodetectors for near-infrared applications, including autonomous vehicles, biometric recognition, and biomedical treatments.