Spectroscopic properties of RBiBO4 (R = Ca, Sr) glasses doped with TiO2

Transparent glasses, melt quenching derived, containing 10RO·20Bi2O3·(70 − x)B2O3·xTiO2 [R = Ca, Sr] with x = 0, 0.5, 1.0 wt% were characterized by X-ray powder diffraction. Physical and spectroscopic properties viz., density, absorption, emission, electron paramagnetic resonance (EPR) and FTIR were investigated. The absorption band around 823 nm in pure glass samples is attributed to the electronic transition of 3P0 to 3P2 of Bi+ radicals. A small absorption hump centered around 609 nm is found in all doped glasses due to 2T2g to 2Eg transition of octahedral Ti3+ ions. The emission results revealed that all the samples exhibit a broad emission band covering entire visible-light range, with λex = 360 nm, centered 470–520 nm corresponds to electronic transition of 3P1 to 1S0 of Bi3+ ions, therefore the present materials can be potentially used as tunable or full-color display systems. And a strong emission around 706 nm with λex = 514 nm due to transition of 2P3/2 to 2P1/2 of Bi2+ ions. In SrO mixed glasses Ti4+ ions effect the environment of Bi3+ ion symmetry units from C2 to C3i. A small EPR signal (at room temperature) is observed in titanium doped glasses due to Ti3+ ions. In both the series with increase of TiO2 concentration BO4 units are gradually converted into BO3 units and new cross linkages are formed, like B–O–Ti, Bi–O–Ti at the expense of B–O–B bonds.

► Spectroscopic studies of TiO2 doped RBiBO4 glasses were studied.
► Due to thermal reduction trace amount of Ti3+ ions are found in all doped glasses.
► These glasses can potentially use as tunable or full-color display materials.
► In SrBiB:Ti glasses the C2 site symmetry of Bi3+ ions is changed to C3i.
► Electron centers are formed in ST05 glass sample.