Impact of CsI concentration, relative humidity, and annealing temperature on lead-free Cs2SnI6 perovskites: Toward visible light photodetectors application

摘要： Physical, electrical, and photodetection properties of stable, lead-free Cs2SnI6 (CSI) perovskite thin films prepared on thermally oxidized Si (SiO2, 100 nm) substrates via direct solution spin coating process are reported. XRD, XPS, and EDS analysis reveal that initial CsI rich-concentration, higher RH% levels (>40%) have an impact on phase formation of CSI films. The porous, sub-lm sized rods of fabricated CSI films are confirmed by FEG-SEM analysis. Contact resistance (Rc) and sheet resistance (Rsh) for CSI films, annealed at 150 (cid:1)C, are decreased up to 37% and 85%, respectively, as compared with those of films processed at 75 (cid:1)C. The photoresponsivity (6 mA/W) and specific detectivity (2.00 (cid:1) 109 Jones) for two-terminal CSI photodetectors are achieved with annealing condition of 100℃ and at a bias voltage of 1 V as well. The preliminary photodetection properties for CSI devices processed at low temperatures indicate that they can be potentially applicable to a flexible, visible light photodetector.