Luminescent Properties of Ce3+ and Bi3+ Doped Cs2LiInCl6 Single Crystals: A Phase-Transition Material Growth

Abstract

The Cs2LiInCl6 (CLIC) crystal holds potential applications in neutron detection and photoluminescent devices. To date, only CLIC powders synthesized via solid-state sintering have been reported, and the preparation of large-sized single crystals remains unexplored. In this work, large-sized, high-quality CLIC single crystals (CLIC:0.5% 1.0% 1.5%Ce/1.5%Bi) were successfully grown by the vertical Bridgman method. And based on phase transition analysis and the incongruent melting characteristics of CLIC, the raw material composition, temperature gradient, crucible lowering rate, and cooling rate were adjusted, successfully achieving growth of the required phase. Then X-ray diffraction analysis confirmed the phase composition of the samples, indicating no impurity phases. Transmission spectroscopy was used to compare the crystal quality before and after process optimization. Photoluminescence spectroscopy measurements revealed a primary excitation peak at 343 nm. Upon Ce 3+ doping, the emission peak shows a slight redshift. Conversely, Bi 3+ doping induced a larger redshift to 426 nm. These emissions are attributed to electronic transitions originating from Ce 3+ and Bi 3+ ions, respectively. Calculations of thermal neutron detection efficiency indicated potential applications in thermal neutron detection. Furthermore, X-ray excited luminescence spectra of CLIC:1%Ce and CLIC:1%Bi exhibited emission peaks centered at 460 nm and 620 nm, respectively. This work presents an effective method for growing complex phases of CLIC, laying the foundation for its growth, preparation, luminescence field and application in neutron detection and other fields.