Inorganic Halide Perovskitoid TlPbI 3 for Ionizing Radiation Detection

Room temperature semiconductor detector (RTSD) materials for gamma-ray and X-ray radiation are in great demand for the nonproliferation of nuclear materials as well as for biomedical imaging applications. Halide perovskites have attracted great attention as emerging and promising RTSD materials. In this contribution, the material synthesis, purification, crystal growth, crystal structure, photoluminescence properties, ionizing radiation detection performance, and electronic structure of the inorganic halide perovskitoid compound TlPbI3 are reported on. This compound crystallizes in the ABX(3) non-perovskite crystal structure with a high density of d = 6.488 g center dot cm(-3), has a wide bandgap of 2.25 eV, and melts congruently at a low temperature of 360 degrees C without phase transitions, which allows for facile growth of high quality crystals with few thermally-activated defects. High-quality TlPbI3 single crystals of centimeter-size are grown using the vertical Bridgman method using purified raw materials. A high electrical resistivity of approximate to 10(12) omega center dot cm is readily obtainable, and detectors made of TlPbI3 single crystals are highly photoresponsive to Ag K-alpha X-rays (22.4 keV), and detects 122 keV gamma-rays from Co-57 radiation source. The electron mobility-lifetime product mu(e)tau(e) was estimated at 1.8 x 10(-5) cm(2)center dot V-1. A high relative static dielectric constant of 35.0 indicates strong capability in screening carrier scattering and charged defects in TlPbI3.