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  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.