Development of Methylammonium Lead Tribromide for Detectors of Ionizing Radiation

Organic-inorganic hybrid perovskites, such as MAPbBr₃, have garnered significant interest in recent years as a potential material for radiation detection due to their outstanding optoelectronic properties, low-cost solution growth, and easily tunable stoichiometry. As a result, perovskites have emerged as a promising low-cost option for spectroscopy and nuclear imaging applications. However, several challenges must be addressed to develop MAPbBr₃ for ionizing radiation detection. This dissertation presents the development of MAPbBr₃ for radiation detection through three interrelated components. First, an improved crystal growth method was designed and studied to address the large size and high-quality crystals needs of radiation detectors. This method has significantly advanced the growth of MAPbBr₃ single crystals, yielding crystals with fewer trap sites and better performance. These crystals have been thoroughly tested and exhibit exceptional purity, thermal stability, and enhanced optical and electrical properties. Their X-ray detection sensitivity is notably higher than existing materials and meets the requirements of radiation detection. Second, Cl-doping with MAPbBr₃ was studied to enhance material properties necessary for radiation detection. MAPbBr₃ single crystals with varying amounts of Cl doping and their chemical, optical, electrical, and radiation detector performance were evaluated. The results showed that Cl doping successfully enhanced the electrical properties of the crystal, resulting in improved electrical resistivity. Gamma-ray and X-ray detection were achieved, and the X-ray sensitivity of 4% Cl-doped MAPbBr₃ single crystal was found to be 155 times better than the currently widely utilized α-Se X-ray detector material. Lastly, the effect of electrode selection on detection performance was investigated by preparing semiconductor devices with various metal combinations. The results showed that chromium and nickel are excellent electrode selections and have demonstrated improved X-ray sensitivity. Although certain challenges remain, the methods and developments presented in this dissertation demonstrate the exceptional potential of MAPbBr₃ for detection of ionizing radiation.