Facile synthesis strategy for cesium tin halide perovskite crystals toward light emitting devices and anti-counterfeiting flexible fiber

All-inorganic metal halide perovskites are widely studied because of their excellent photoelectric properties. However, due to the toxicity of CsPbX3 (X = Cl, Br, I) perovskites, it is difficult to apply them on a large scale. The lead-free nature and air stability make Cs2SnX6 (X = Cl, Br, I) perovskites possible candidates to replace CsPbX3 perovskites. Herein, we report the perovskite crystals (PCs) based on Te(iv)-doped Cs2SnCl6: Cs2Sn1-xTexCl6. Cs2Sn1-xTexCl6 PCs showed yellow emission under a 365 nm ultraviolet lamp. The photoluminescence quantum yield (PLQY) of Cs2Sn0.94Te0.06Cl6 PCs was 57.09%, which was proposed to be from the triplet Te(iv) ion P-3(1) -> S-1(0) self-trapping excitons (STE) recombination. The perovskite crystals can be used to fabricate light-emitting diodes (LEDs). The fiber paper prepared from aramid chopped fibers (ACFs) and polyphenylene sulfide (PPS) fibers showed a bright yellow light under 365 nm ultraviolet light after being post-processed with Cs2Sn1-xTexCl6 PCs solution. The ACFs/PPS compound fiber paper modified with Cs2Sn1-xTexCl6 PCs maintained exceptional optical properties and could be stored in air for more than 4500 h. The fluorescence performance of the modified ACFs/PPS compound fiber paper could be applied to fluorescence anti-counterfeiting. The modification strategy and the applications in this work will provide a good choice for studying the optical performance of perovskites and broaden the application of ACFs/PPS compound fiber paper.

Automated summary

Due to the toxicity of CsPbX3 perovskites, Cs2SnX6 perovskites with lead-free nature and air stability are considered as possible candidates to replace them. Te(iv)-doped Cs2SnCl6 perovskite crystals (PCs) were synthesized and showed yellow emission under a 365 nm ultraviolet lamp. PCs of Cs2Sn0.94Te0.06Cl6 exhibited a high photoluminescence quantum yield (PLQY) of 57.09%, which was attributed to triplet Te(iv) ion self-trapping excitons. The modified fiber paper with Cs2Sn1-xTexCl6 PCs showed exceptional optical properties and fluorescence performance for anti-counterfeiting applications.