All-Inorganic Lead-Free Heterometallic Cs4MnBi2Cl12 Perovskite Single Crystal with Highly Efficient Orange Emission

A luminescent all-inorganic manganese-bismuth heterometallic Cs4MnBi2Cl12 perovskite single crystal has been synthesized with a [BiCl6]3−-[MnCl6]4−-[BiCl6]3− triple-layered two-dimensional structure. Benefit from the effective energy transfer from [BiCl6]3− octahedron donor to luminescent [MnCl6]4− acceptor, Cs4MnBi2Cl12 shows a photoluminescence quantum yield (PLQY) of up to 25.7% (~610 nm), 51-fold higher than the Bi unalloyed CsMnCl3·2H2O counterpart. Suggested by the theoretical calculations, Bi and Mn exhibit hybridization in conduction and valence band, which further results in a favorable low activation energy for exciton transfer (~23 meV). By virtue of all-inorganic chemical composition, Cs4MnBi2Cl12 exhibits impressive stability toward moisture, light, and heat. Furthermore, Cs4MnBi2Cl12 features strong soft X-ray attenuation and bright radiative luminescence under X-ray excitation, which pave a way for its application in medical flat-panel X-ray digital radiography. This work presents a new avenue toward fabrication of function-directed material with tailored photoelectric properties.