High stability of robust anti-thermal-quenching lead-free double perovskite crystals for optoelectronic devices and high-performance fibers

Lead-free double perovskites are environmentally friendly, and their good photoelectric efficiency has received widespread attention. However, the stability and efficiency of lead-free perovskites need to be further improved to meet the growing application needs. In this study, thermally quenched perovskite (Cs2NaHoCl6) crystals (PCs) were successfully synthesized by co-precipitation. By doping with Sb3+, the excitation wavelength of the original perovskite increased significantly to 250–360 nm, and the emission wavelength of the original perovskite also increased significantly to 660 nm. Cs2NaHoCl6:Sb3+ PCs are made of red and white light-emitting diodes (LEDs) for general lighting applications. In addition, Cs2NaHoCl6:Sb3+ PCs are made into flexible luminescent fibers with aramid/polyphenylene sulfide (ACFs/PPS) composite fibers. Based on the good thermal quenching resistance of Cs2NaHoCl6:Sb3+ PCs, the flexible luminescent fibers showed excellent high-temperature luminescence stability. At 125 °C, flexible luminescent fibers retained 99.8% of the original luminescence intensity; at 250 °C, they retained 75.6% of the original. These flexible luminescent fibers have the potential to be used in fluorescence detection in high-temperature environments. In summary, this study used a simple method to prepare lead-free perovskites with good optical properties and stability, expanding the application of perovskites in the field of fibers.