Sensitive detection of ultraviolet and x-ray radiation with photoluminescent nano-matter based on rare-earth doped compounds

There is ever growing interest in sensitive detection of ultraviolet (UV) and x-ray radiation. We report on our efforts to develop photoluminescent spectrum downshifting nanomaterials based on perovskites and oxysulphides doped with rare-earth (RE) ions of Eu³⁺ for sensitive UV/X-ray detection. We used the ex-situ method of doping pre-made nanoparticles (NPs) of perovskite CsPbBr₃ with Eu³⁺ ions. Suspension of the NPs in Toluene was mixed with the solution of anhydrous EuCl₃ in anhydrous DMF. The result was shifting spectral peak of perovskite-related photoluminescence (PL) under UV excitation from 510nm to 452nm and a weak Eu-related PL. A PL screen made of compressed nano-powder of Gd₂O₂S:Eu integrated with a silicon avalanche photodiode was demonstrated as a receiver in a solar-blind non-line-of-sight free space optical communication system in lab environment. The signal was simulated by a series of periodic pulses transmitted by a chopped 265-nm UV-C LED. The signal-to-noise ratio of the receiver was ~26 dB. Gd2O2S: Eu nano-powder was also used in a scintillating screen for x-ray imaging of steel washers wrapped in black paper. The images were clearly seen with a naked eye at room illumination. The results are useful for further development of UV and x-ray sensors.