Engineering Solid-Liquid Interface Leading to Excellent Quality CsPbBr3 Single Crystal With High Spectral Resolution of Gammarays

Abstract

All-inorganic metal halide perovskite CsPbBr3 crystal was regarded an attractive alternative to high purity Ge and CdZnTe for room temperature γ-ray detection. However, high γ-ray resolution is only observable in small CsPbBr3 crystal, more practical and deployable large crystal exhibits very low, and even no detection efficiency, thereby thwarting prospects for cost-effective room temperature γ-ray detection. The poor performance of large crystal is attributed to the unexpected secondary phase inclusion during crystal growth, which trapped the generated carriers. Here, we engineered the solid-liquid interface during crystal growth by optimizing the temperature gradient and growth velocity. This terminates the unfavorable formation of secondary phase, leading to large (Φ30 mm) excellent quality crystal. The crystal exhibits a remarkable high carrier mobility of 35.4 cm–2·V–1·s–1, and resolves the peak of 137Cs @662 keV γ-ray at an energy resolution of 19.51%. These values are the highest among crystal with same dimension.

Keywords: Interface engineering, Secondary phase inclusion, Nano-scale defect elimination, CsPbBr3 perovskites, Gamma-ray detection