Developing Perovskite Halide Scintillator thin films for Fast-Timing applications

The mixed metal halide perovskite materials have generated interest in numerous optoelectronic applications, including solar cells, light emitting diodes, and others. The general form of the perovskite structure is given by ABX3, and in the case of the mixed metal halides, the A and B site are organic molecules or transition metal atoms, and the X site is typically a mixture of bromine and iodine. It was recently reported that the inorganic perovskite CsPbBr3 scintillates as a single crystal and in thin film form. The light emission from a crystal of CsPbBr3 was found to have X-ray excited luminescence yields of >120,000 photons/MeV at low temperatures, and there have been reports using this material in thin film form producing ~21,000 photons/MeV. These reports suggest that the perovskite scintillators are extremely fast, and bright. Yet, these numbers also indicate that there is considerable room for improvement in the performance of thin film perovskite scintillators. Here, we explore the synthesis of scintillating perovskite CsPbBr3 for high resolution X-ray imaging. Nanosheets of CsPbBr3 were formed using chemical synthesis, with the thin film scintillator formed by low-cost drop casting and spin coating. Additionally, we explore different types of perovskite scintillators by changing the composition of the thin film, and tuning the size of the colloidal nanosheets. Due to the potential for high brightness, high absorption efficiency, and fast timing, this scintillator may be useful for high frame rate, low-flux applications.