Low defects density CsPbBr3 single crystals grown by an additive assisted method for gamma-ray detection

Metal halide perovskites have arisen as a new family of semiconductors for radiation detectors due to their high stopping power, large and balanced electron-hole mobility-lifetime (μτ) product, and tunable bandgap. Here, we report a simple and low-cost solution processing approach using additive-assisted inverse temperature crystallization (ITC) to grow cesium lead bromide (CsPbBr3) single crystals with low-defect density. Crystals grown from precursor solutions without additives tend to grow fastest along the [002] direction, resulting in crystals shaped as small elongated bars. The addition of choline bromide (CB) proves to mediate the crystallization process to produce large single crystals with a cuboid shape, allowing for more practical fabrication of gamma-ray detectors. This new additive-assisted growth method also improves the resulting crystal quality to yield a reduction in the density of trap states by over one order of magnitude, relative to a crystal grown without CB. The detector fabricated from a CB-assisted solution-grown perovskite CsPbBr3 single crystal is able to acquire an energy spectrum from a cesium-137 (137Cs) source with a resolution of 5.5% at 662 keV.