Recently, Prof. Han Keli’s team from the Institute of Frontier and Interdisciplinary Science of Shandong University have made new progress in the field of zero-dimensional lead-free metal halide luminescent materials and published a research paper entitled “Excitation-Dependent Emission in All-Inorganic Lead-Free Cs₂ScCl₅·H₂O Perovskite Crystals”in Laser & Photonics Reviews(IF=13.138). Shandong University is the first author institute. Associate researcher Zhang Ruiling and doctoral student Xu Xin are the co-first authors. Professor Han Keli is the corresponding author.

Materials with excitation-dependent emission have gained considerable attention due to their potential applications in encrypted information storage, multicolor display and anti-counterfeiting fields. Their emission colors can be tuned simply by adjusting excitation wavelengths, without changing their size or chemical composition. The excitation-dependent emission has been observed in metal complexes, small molecules, polymers and carbon-based semiconductors. Recently, low-dimensional lead-free metal halides have attracted much attention because of their improved chemical stability and superior optical properties. The unique structural properties can facilitate the construction of multiple luminescent centers, resulting in excitation-wavelength-dependent emission. However, most of the reports are based on organic-inorganic metal halide hybrids. There is a lack of research on all-inorganic low-dimensional lead-free metal halides with excitation-wavelength dependent emission.

In this work, the authors have successfully synthesized an all-inorganic perovskite Cs₂ScCl₅·H₂O with excitation-dependent emission behavior. The emission color can be simply tuned from blue-green to white to yellow by changing excitation wavelengths. The origin of the interesting tunable emission is ascribed to the contribution of two different STE states based on temperature-dependent and time-resolved PL measurements as well as fs TA spectroscopy analysis. In addition, Sb³⁺ions have been successfully doped into Cs₂ScCl₅·H₂O single crystals, leading to enhanced photoluminescence with about 100% PLQY. This work provides new insights into the excitation-dependent emission in all-inorganic semiconductors, and presents a successful strategy to develop environmentally-friendly high-performance emitters.

This work was supported by the Artificial Photosynthesis Basic Science Center, the National Natural Science Foundation of China, and the Natural Science Foundation of Shandong Province.

Link to the article: https://onlinelibrary.wiley.com/doi/full/10.1002/lpor.202100689