Sensitivity and Detection Limit of Spectroscopic‐Grade Perovskite CsPbBr₃ Crystal for Hard X‐Ray Detection

Abstract

Abstract Spectroscopic‐grade single crystal detectors can register the energies of individual X‐ray interactions enabling photon‐counting systems with superior resolution over traditional photoconductive X‐ray detection systems. Current technical challenges have limited the preparation of perovskite semiconductors for energy‐discrimination X‐ray photon‐counting detection. Here, this work reports the deployment of a spectroscopic‐grade CsPbBr 3 Schottky detector under reverse bias for continuum hard X‐ray detection in both the photocurrent and spectroscopic schemes. High surface barriers of ≈ 1 eV are formed by depositing solid bismuth and gold contacts. The spectroscopic response under a hard X‐ray source is assessed in resolving the characteristic X‐ray peak. The methodology in enhancing X‐ray sensitivity by controlling the X‐ray energies and flux, and voltage, is described. The X‐ray sensitivity varies between a few tens to over 8000 μC Gy air −1 cm −2 . The detectable dose rate of the CsPbBr 3 detectors is as low as 0.02 nGy air s −1 in the energy discrimination configuration. Finally, the unbiased CsPbBr 3 device forms a spontaneous contact potential difference of about 0.7 V enabling high quality of the CsPbBr 3 single crystals to operate in “passive” self‐powered X‐ray detection mode and the X‐ray sensitivity is estimated as 14 μC Gy air −1 cm −2 . The great potential of spectroscopic‐grade CsPbBr 3 devices for X‐ray photon‐counting systems is anticipated in this work.