Investigation on energy resolution of CsPbBr3 detectors: from charge transport behavior to device configuration

Abstract

All-inorganic perovskite CsPbBr₃ serving as an ionizing radiation material exhibits tremendous potential in many fields. However, its applications are limited by poor energy resolution (ER), which is significantly associated with both material properties and device configurations. In this work, the effects of applied electric field, crystal thickness and carrier transport properties on the ER of CsPbBr₃ detectors are investigated by theoretical simulation. For the first time, the (μτ)_e/(μτ)_h ratio as a critical factor that affects the ER has been revealed, which provides guidance on electrode configuration design for enhancing charge collection efficiency and minimizing the tailing in pulse height spectra. Additionally, experimental investigations on electrode structures of CsPbBr₃ detectors have been conducted. The resulting ER of CsPbBr₃ detectors is improved from 30.3% (planar electrode) to 11.76% (quasi-hemispherical electrode) at 59.5 keV γ-rays. Furthermore, the quasi-hemispherical detector also achieves an ER of 11.47% at ¹³⁷Cs 662 keV γ-rays, showing great potential for high-energy γ-ray detection. These experimental results are in good accordance with the simulation calculations, demonstrating that both crystallization improvement and optimization of the device configuration can enhance the ER of radiation detectors.