Perovskite CsPbBr₃ Single‐Crystal Detector Operating at 10¹⁰ Photons s⁻¹ mm⁻² for Ultra‐High Flux X‐ray Detection

Abstract Semiconductors for detecting hard radiation are confronted with considerable problems when operating at high photon fluxes. A perovskite CsPbBr 3 single‐crystal detector capable of operating at X‐ray fluxes of up to 10 10 photons s −1 mm −2 with beam area ≤ 0.25 mm 2 at 58.61 keV for current‐mode X‐ray detection is reported. The spectrometer‐grade melt‐grown CsPbBr 3 detectors show a gamma‐ray energy resolution of ~7.5% at 122 keV for 57 Co and dark current as low as 4.3 nA (0.5 nA mm −2 ) at a reverse bias voltage of 200 V (118 V mm −1 ). The detector is tested at X‐ray energies of 8.2, 10, and 58.61 keV at a synchrotron light source under a reverse bias voltage of up to 1000 V (588 V mm −1 ). Under a sufficiently high bias voltage and within several hundreds of seconds X‐ray exposure, good photocurrent linearity (goodness of fit R 2 > 0.99) and reproducibility are obtained up to a flux of ≈10 10 photons s −1 mm −2 at beam area 0.25 mm 2 with Lower Limit of Detection of ≈10 5 photons s −1 mm −2 and Charge Collection Efficiency of ≈100% for 58.61 keV X‐rays. Accordingly, wide application of CsPbBr 3 detectors in high‐flux X‐ray detection is anticipated.