Local structure, spectroscopy and luminescence of the Li2B4O7:Cu,Eu glass

The Li2B4O7:Cu,Eu glass containing 1.0 mol.% CuO and Eu2O3 impurities was obtained and studied by XRD, EPR, optical absorption, and photoluminescence techniques. Parameters of local structure (interatomic distances and coordination numbers) were derived from XRD data analysis. The EPR and optical absorption, emission, photoluminescence excitation show that the Cu impurity is incorporated into the Li2B4O7 glass as Cu2+ (3d9) and Cu+ (3d10) ions. The Cu2+ ions in Li2B4O7:Cu,Eu glass show characteristic EPR and optical absorption spectra. Spin Hamiltonian parameters of the Cu2+ EPR spectrum were determined. Optical absorption spectrum of the Li2B4O7: Cu,Eu glass was analysed and interpreted. Optical band gap and Urbach energy of the Li2B4O7:Cu,Eu glass were evaluated. Photoluminescence spectra of the Li2B4O7:Cu,Eu glass reveal broad blue emission band of Cu+ (3d94s1 -* 3d10 transition) and narrow emission bands of Eu3+ (4f6) ions belonging to the 5D0 -* 7FJ (J = 0 - 4) transitions with characteristic decay kinetics.