Experimental and theoretical study of pure and doped crystals: Gd2O2S, Gd2O2S:Eu3+ and Gd2O2S:Tb3+

Quantum chemistry and experimental method were used to study on pure and doped Gd2O2S crystals in this paper. The band structure and DOS diagrams of pure and doped Gd2O2S crystals which calculated by using DFT (Density Functional Theory) method were illustrated to explain the luminescent properties of impurities in crystals. The calculations of the crystal structure were finished by using the program of CASTEP (Cambridge Sequential Total Energy Package). The samples showed the characteristic emissions of Tb3+ ions with D-5(4)-7F(J) transitions and Eu3+ ions with D-5(0)-7F(J) transitions which emit pure green luminescence and red luminescence respectively. The experimental excitation spectra of Tb3+ and Eu3+ doped Gd2O2S are in agreement of the DOS diagrams over the explored energy range, which has allowed a better understanding of different luminescence mechanisms of Tb3+ and Eu3+ in Gd2O2S crystals. (C) 2012 Elsevier B.V. All rights reserved.