Heterojunction Engineering of All-Inorganic CsPbI3 Perovskite for High-Responsivity SWIR Photodetectors Performed at Room Temperature

Short-wave infrared (SWIR) light, 0.9–2.5 μm wavelengths, has widespread applications, including inspection processes, nighttime imaging, and machine vision. As such, there is increasing demand for practical and effective SWIR detectors. Many current SWIR photodetectors are based on high-cost materials and require cryogenic cooling. Perovskite materials, including CsPbI3, have been effectively used as photodetectors in the UV to near IR ranges, but their large bandgaps limit their use for lower energy SWIR light. In this report we introduce an all-inorganic perovskite photodetector based on CsPbI3 with heterojunction engineering for efficient and practical detection in the SWIR range at room temperature. The devices undergo a simple, solution-based fabrication process which includes spin-coating under ambient conditions and moderate annealing temperatures. Without additional cooling, the SWIR devices produce excellent results at room temperature with responsivity of 1.65 × 103 A W−1 and a specific detectivity of 8.0 × 1010 Jones under 0.28 mW cm−2 of 1310 nm light and bias of −5 V. This material shows not only high response but also high sensitivity, making it stand out in the field of SWIR photodetection with the additional benefits of low-cost production and room temperature operation.