Abstract
All-inorganic perovskites, renowned for their superior photoelectric properties, have found extensive applications across diverse fields. Among these, perovskite-based visible-blind ultraviolet photodetection and X-ray detection have emerged as rapidly evolving research hotspots. Herein, the accumulation of PbI(2) on the crystal surface is observed and verified for the first time. Through the slow solvent evaporation method at 70 °C to avoid PbI(2) accumulation, a high-quality transparent colorless Cs(4)PbI(6) single crystal with low defect density and high phase purity can be successfully fabricated, which exhibits excellent detection properties due to its wide bandgap of 3.3 eV. The zero-dimensional transparent colorless Cs(4)PbI(6) single-crystal-based visible-blind ultraviolet photodetector shows a high responsivity as much as 35.10 A/W, an external quantum efficiency as high as 1.07 × 10(4)%, and a detectivity as large as 2.45 × 10(14) Jones, with an extremely fast response speed of ∼40 μs and excellent long-term stability. In addition, transparent and colorless Cs(4)PbI(6) is also used in direct-type X-ray detectors exhibiting high sensitivity. Under the irradiation of an X-ray source energy (160 keV) close to that of medical CT, the sensitivity of the device can reach 154.84 μC·Gy(air) (-1)·cm(-2), with the detection limit lower than the safe value required for medical diagnosis.