Lanthanide-doped nanoparticles for sensitive photodetectors of short-wave radiation

There is ever growing interest in sensitive detection of short wavelength (SWL) radiation, ultraviolet (UV) and X-rays. We report on our efforts to develop sensitive SWL detectors based on the nanoparticles (NPs) of lanthanide (Ln) doped Cs-Pb-bromide perovskite and oxysulfides that down-convert the spectrum of SWL radiation into visible and near-infrared (NIR) light. The spectrum of this light matches the spectral response of inexpensive and rugged silicon avalanche photo diodes (APDs) and image sensors with an electron gain of >10⁶. Synthesized Eu-doped perovskite NPs demonstrated a down-shifted visible-NIR photoluminescence (PL) response to UV radiation with the spectral peaks attributed to both perovskite matrix and Eu dopant. A scintillating screen made of red nanophosphor Gd₂O₂S: Eu was used for X-ray see-through imaging of a metal object hidden in an opaque medium. Integration of the nanophosphor with a silicon APD made it possible to detect pulsating X-rays at frequencies of 20 and 40Hz with a signal-to-noise ration of ~5. The results obtained might be used in the field of sensitive detection of SWL radiation.