Insight into the high-voltage stability of perovskite ionizing radiation detector: From interfacial reaction to performance degradation

The stability of perovskite-based ionizing radiation detectors has garnered widespread concern. Here, the Schottky contact devices were fabricated using CsPbBr₃ single crystals with either In or Bi as the anode. This research focused on analyzing the peak-centroid and energy resolution of pulse height spectra when illuminated by ²⁴¹Am α particles. The cause of the operational instability in the Schottky CsPbBr₃ devices at high voltage was determined to be the result of chemical and electrochemical reactions between the anode metal and perovskite. These reactions were facilitated by the ion migration within the crystals. Moreover, there was a shift in the energy level of the reacted CsPbBr₃, resulting in a decrease in the charge collection efficiency. By utilizing a CsPbBr₃ crystal with a high ion migration activation energy of 0.42 eV and a Bi anode that suppresses interface reactions, a peak-centroid variation of less than ±1% under a bias of ∼2667 V·cm⁻¹ over a period of 4 months was obtained. These results are attributed to a comprehensive grasp of the high-voltage stability challenges associated with perovskite ionizing radiation detectors.