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

Abstract 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.