Effects of Ce3+ substitution on the local structure of cerium and scintillation properties of CLLBC:Ce crystals

In this work, a strategy of controlling the doping concentration of cerium is adopted to improve the gamma response performance of cutting-edge Cs2LiLa(Br,Cl)6:Ce (CLLBC:Ce) single crystal scintillators. A serial of Ce3+-doped Cs2LiLaBr5.4Cl0.6 single crystals with a size of Ф12 mm × 50 mm were successfully grown by the Bridgman method. Two different lattice positions of Ce3+ in the CLLBC crystal were identified by using spectral and decay kinetics, Raman spectra, X-ray photoelectron spectroscopy, refined XRD. The effects of cerium substitution amount on local structure, crystal structure, luminescence properties and the scintillation properties were systematically investigated. As the Ce3+ content increased, the light yield and energy resolution of CLLBC:Ce were first improved and then deteriorated. The Cs2LiLaBr5.4Cl0.6:2 mol% Ce crystal has a highest light yield and optimal energy resolution of 3.70 % under 137[email protected] keV excitation.