Guanidinium-Based Manganese(II) Bromide with High Glass-Forming Ability for Thermoplastic Curved X-ray Imaging

The development of large-area transparent organic-inorganic hybrid metal halide (OIMH) scintillation screens is restricted by the anisotropic single-crystal growth, numerous grain boundaries in polycrystalline wafers, and inhomogeneous dispersion in perovskite-polymer composite films. The crystal-glass phase transition of OIMH materials may provide a promising solution for the above significant challenges. Herein, a new class of transparent amorphous guanidinium-based manganese bromide glasses, (DPG) 2 MnBr 4 and (DOTG) 2 MnBr 4 (DPG = 1,3-diphenylguanidinium, DOTG = 1,3-di-o-tolylguanidinium), are synthesized through a low-temperature melt-quenching process. The (DOTG) 2 MnBr 4 shows impressive glass-forming ability because of large viscosity ( η ) at the melting temperature ( T m ) ( η ( T m ) = 3426 mPa·s) and small fragility index ( m = 52.35), which can be a potential glass scintillator. The large-area (e.g., 13 cm × 13 cm) transparent amorphous (DOTG) 2 MnBr 4 glass scintillator shows high light transmittance of > 80%, a low detection limit of 237.3 nGy s −1 and high X-ray imaging spatial resolution of 12 lp mm −1 . Interestingly, the glass transition temperature of < 40 °C gives (DOTG) 2 MnBr 4 glass unique thermoplastic properties, allowing it to conform to irregularly shaped objects and reduce the distortion in X-ray imaging.