Modulation of Halogens in Organic Manganese Halides for High-Resolution and Large-area Flexible X-ray Imaging

Manganese-based organic metal halides, due to their excellent optoelectronic properties and stable chemical nature, have been widely applied in optoelectronic devices and sensors. In this study, through rational modulation of halogens, three novel zero-dimensional organic manganese halides (C6H8N)2MnX4 (X=Cl, Br, I) were obtained by adjusting the halogen via the solvent evaporation method. Attributed to the d-d electronic transition of Mn2+ in the tetrahedral-coordinated [MnX4]2- polyhedron, all samples exhibit strong green emission. Notably, the (C6H8N)2MnBr4 was demonstrated with a remarkable light yield of 18224 photons MeV−1 and a low detection limit of 1.9 μGy s−1, which is below the X-ray diagnostic limit and even superior to the commercial BGO scintillator. Moreover, a 9 cm×9 cm flexible scintillator film was successfully fabricated by mixing the (C6H8N)2MnBr4 crystalline powder with polymethyl methacrylate, manifesting superior radiation stability and an X-ray imaging resolution of 12.1 lp mm−1. Notably, the X-ray images captured by the flexible film demonstrate distinguished clarity as adhering perfectly to curved metal sheets. The combination of excellent performance and facile solution processing open new opportunities for low-cost, high-performance organic metal halides based large-area flexible scintillators for X-ray detection and imaging.