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

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 CsPbBr₃ 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 CsPbBr₃ detectors is as low as 0.02 nGy_air s⁻¹ in the energy discrimination configuration. Finally, the unbiased CsPbBr₃ device forms a spontaneous contact potential difference of about 0.7 V enabling high quality of the CsPbBr₃ 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 CsPbBr₃ devices for X-ray photon-counting systems is anticipated in this work.