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 vapor-assisted 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.