Perovskite CsPbBr3: Material Purity, Crystal Defects, and Detector Performance

The perovskite CsPbBr3is a new generation semiconductor in the field of X-ray and g-ray detection. The fundamental physical properties of CsPbBr3well meet the requirements for high energy detector applications, with direct band gap (orange color, 2.25 eV), high density (4.85 g/cm3), attenuation coefficient comparable to CZT, and high resistivity (109-1010W• cm) and carrier mobility-lifetime product (10-3- 10-4cm2/V). We developed a new chemical process for inexpensive material production with an excellent purity (>99.999%) and quantitative (>95%) yield. Large crystals of CsPbBr3grown by the Bridgman method show high transparency (85% transmission in FT-IR spectroscopy) and well resolved characteristic peaks in g-ray spectroscopy with241Am,57Co, and137Cs and high flux X-rays as radiation sources. The energy resolution of the planar detector has reached the value close to 1% from the137Cs g-ray irradiation. One of the major challenges currently lying in practical applications of this material is the crystal defects including domain and twin boundaries and the charge carrier trap states present in the material, all of which should be minimized to maximize the detector sensitivity. This presentation will give an overview of the process of synthesis, crystal growth and optimization efforts to mitigate the issues above to enhance crystal quality and detector performance of CsPbBr3.