Compared with the widely reported MAPbBr 3 single crystals, formamidinium-based (FA-based) hybrid perovskites FAPbBr 3 (FPB) with superior chemical and structure stability are expected to be more efficient and perform as more reliable radiation detectors at room temperature. Here, we employ an improved inverse temperature crystallization method to grow FPB bulk single crystals, where issues associated with the retrograde solubility behavior are resolved. A crystal growth phase diagram has been proposed, and accordingly, growth parameters are optimized to avoid the formation of NH 4 Pb 2 Br 5 secondary phase. The resulting FPB crystals exhibit a high resistivity of 2.8 × 10 9 Ω•cm and high electron and hole mobility−lifetime products (μτ) of 8.0 × 10 −4 and 1.1 × 10 −3 cm 2 •V −1 , respectively. Simultaneously, the electron and hole mobilities (μ) are evaluated to be 22.2 and 66.1 cm 2 •V −1 •s −1 , respectively, based on the time-of-flight technique. Furthermore, a Au/FPB SC/Au detector is constructed that demonstrates a resolvable gamma peak from 59.5 keV 241 Am γ-rays at room temperature for the first time. An energy resolution of 40.1% is obtained at 30 V by collecting the hole signals. These results demonstrate the great potential of FAPbBr 3 as a hybrid material for γ-ray spectroscopy and imaging.

High-quality organic-inorganic halide perovskite brings an opportunity for ideal nuclear radiation detection due to its large carrier mobility, lifetime, and heavy atoms. However, the relatively low bulk resistivity restricts its development for alpha particles and X/γ-ray detectors. Here, we report on the MAPbBr 3−x I x (MPB:I) perovskite crystals grown using the modified inverse temperature crystallization method. Based on the measured supersolubility and solubility curves, the heating procedure was accurately designed to control the nucleation and growth rate. The resulting MPB:I single crystals exhibit higher bulk resistivity of 1.4 × 10 9 cm, which is 10 times that obtained from the traditional inverse temperature crystallization method. Finally, an uncollimated 0.8 µCi 241 Am 5.48 MeV alpha particles source was adopted to evaluate the MPB:I single crystals at room temperature condition. The electron mobility (µ e ) and mobility-lifetime product (µτ ) e of (264.6 ± 6.5) cm 2 V −1 s −1 and (2.6 ± 0.3) × 10 −3 cm 2 /V, respectively, were obtained.

All-inorganic perovskite CsPbBr3 serving as an ionizing radiation material exhibits tremendous potential in many fields. However, the applications are limited by the poor energy resolution (ER), which is significantly associated...

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