Precursor Engineering for Solution Method-Grown Spectroscopy-Grade CsPbBr₃ Crystals with High Energy Resolution

A CsPbBr₃ single crystal exhibits great potentials in X-ray/gamma-ray spectroscopy and imaging. Here, an inverse temperature crystallization (ITC) method with modified precursor composition is proposed to prepare CsPbBr₃ single crystals. The introduction of adduct PbBr₂·2DMSO, synthesized by the antisolvent vaporassisted crystallization method, in the precursor solution gives rise to superior crystallization with a lower impurity concentration and higher resistivity of 6.37 × 10⁹ Ω·cm, as well as a higher hole mobility (50.7 cm²·V^-1·s^-1). Furthermore, a low dark current of 2.3 nA is obtained at a bias of .100 V based on an as-grown crystal with a thickness of 1 mm, according to the asymmetric Au/CsPbBr₃/Sn structure. The resulting asymmetric planar detectors achieve the high peak-to-valley ratio pulse height spectra with an energy resolution of 7.66%, illuminated by an uncollimated ²⁴¹Am@5.5 MeV α particle. Simultaneously, an energy resolution of 13.5% is realized when irradiated by a 59.5 keV ²⁴¹Am γ-ray source at room temperature. The thermally stimulated current (TSC) spectra indicate that the density of deep energy-level trap is significantly reduced in the CsPbBr₃ crystals grown by PbBr₂·2DMSO-modified precursor solution, which is consistent with the high performance in radiation detection.