Deltaflex

TRPL kinetics was detected by HORIBA DeltaFlex ultrafast time-resolved fluorescence spectrometer, where the excitation wavelength was 405 nm at 1 µJ cm⁻² and the detection time scale was 40 ns.

The structural characterizations of CsCdCl₃ crystals were examined by XRD (TD‐3500, China). The morphology and chemical compositions were observed by SEM (JEOL, JSM‐7500F) and EDS. The microstructure was further characterized by TEM (JEOL, JEM‐3010). Absorption spectrum was performed by an UV–vis spectrophotometer (UV–vis, Hitachi UH4150). PL/PLE spectra were monitored by the fluorescence spectrophotometer (Horiba; Fluorolog‐3). The PLQY of the CsCdCl₃ crystals was performed in FLS‐1000 spectrometer with a calibrated integrating sphere. The transient PL spectrum of CsCdCl₃ crystals was measured by the time‐resolved spectrometer (Delta‐flex, Horiba Scientific). TGA was obtained successfully by TGA Q5000IR under the N₂ atmosphere. The LPL decay curve was monitored at 580 nm by thermoluminescence spectrometer (TOSL‐3DS). When the remained signal level was two times to that of background, the corresponding time was considered as the LPL decay time. The samples were charged with a 254 nm lamp for 5 min before transferring into a heating chamber. TOSL‐3DS thermoluminescence spectrometer was used to obtain the thermoluminescence spectrum at a heating rate of 1 K s⁻¹ (Guangzhou Rongfan Science and Technology Co., Ltd).