Transparent glassy composites incorporating lead-free anti-perovskite halide nanocrystals enable tunable emission and ultrastable X-ray imaging

Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A=alkali metal;M=transition metal;X=Cl,Br,I),a class of electron-inverted perovskite derivatives,exhibit robust structural and photophysical stability.Here,we design and prepare a lead-free[MnBr_(4)]BrCs_(3) anti-perovskite nanocrystal(NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 Ip mm^(-1).Due to the unique crystal structure and the protection of the glass matrix,the Cs_(3)MnBr_(5) NC-embedded glass exhibits excellent X-ray irradiation stability,thermal stability,and water resistance.These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite.This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.

PbS quantum dots and Ba F_(2):Tm^(3+) nanocrystals co-doped glass for ultra-broadband near-infrared emission [Invited]

With the rapid growth of optical communications traffic,the demand for broadband optical amplifiers continues to increase.It is necessary to develop a gain medium that covers more optical communication bands.We precipitated PbS quantum dots(QDs) and Ba F_(2):Tm^(3+) nanocrystals (NCs) in the same glass to form two independent emission centers.The Ba F_(2)NCs in the glass can provide a crystal field environment with low phonon energy for rare earth (RE) ions and prevent the energy transfer between RE ions and PbS QDs.By adjusting the heat treatment schedule,the emission of the two luminescence centers from PbS QDs and Tm^(3+) ions perfectly splices and covers the ultra-broadband near-infrared emission from 1200 nm to 2000 nm with bandwidth over 430 nm.Therefore,it is expected to be a promising broadband gain medium for fiber amplifiers.