DX-like centers in NaI:Tl upon aliovalent codoping

摘要: Aliovalent doping has been recently shown to remarkably improve energy resolution in some halide scintillators. Based on first-principles calculations we report the formation of DX-like centers a well-known scintillator material, Tl-doped NaI (NaI:Tl), when codoped with Ca or Ba. Our indicate net binding favoring defect complex (TlNa−+CaNa+) involving new cation-cation bond, instead isolated substitutional defects. The pair properties deep acceptor complex. Doping aliovalent anion impurity Te is also found induce centers, which can act as effective electron hole traps. trapped TeI0 involves large lattice relaxation and an adjacent iodine, consistent extrinsic self-trapping hole. Thus, contrast positive effect achieved by co-doping rare-earth tri-halides LaBr3:Ce CeBr3:Ca reported recently, donor-like cations Ca, Ba, acceptor-l...