Spectroscopic and mechanical studies of lithium aluminoborate glasses doped with chromium ions

Optical Transitions from Hexavalent Chromium in Lithium-Borate Glasses

“…The spectra of these slightly doped systems exhibit distinguishable near-edge absorption peaks, which lie at the origin of such misleading edge assignment. In fact, these absorption features (red arrows) are brought by Cr 6+ characteristic optical transitions commonly found at ~ 338 and ~ 370 nm, and are assigned to 4 A2g→ 4 T1g and to 4 A2g→ 2 A1g transition, respectively [1][2][3][4][33][34][35][36][37]. Actually, Cr 6+ is optically inactive since it has 3d 0 configuration, but the charge transfer taking place between O and Cr ions leads to the optically active Cr 5+ (3d 1 2p 5 ) state [1][2][3][38][39][40][41].…”

“…Colored glasses acquired a lot of interest in commercial business as they are favored in home decoration and many other technological applications. Optical transitions between energy split d and f levels in transition metals (TM) and rare earth ions, respectively, are the main origin for color effects [1][2][3][4][5][6][7][8][9][10]. For precise and controlled tunability of glasses color, for example, it is appealing to search for suitable glass hosts capable of accommodating varies concentrations of TM ions.…”

Optical transitions from hexavalent chromium in lithium-borate glasses

“…The spectra of these slightly doped systems exhibit distinguishable near-edge absorption peaks, which lie at the origin of such misleading edge assignment. In fact, these absorption features (red arrows) are brought by Cr 6+ characteristic optical transitions commonly found at ~ 338 and ~ 370 nm, and are assigned to 4 A2g→ 4 T1g and to 4 A2g→ 2 A1g transition, respectively [1][2][3][4][33][34][35][36][37]. Actually, Cr 6+ is optically inactive since it has 3d 0 configuration, but the charge transfer taking place between O and Cr ions leads to the optically active Cr 5+ (3d 1 2p 5 ) state [1][2][3][38][39][40][41].…”

“…In fact, these absorption features (red arrows) are brought by Cr 6+ characteristic optical transitions commonly found at ~ 338 and ~ 370 nm, and are assigned to 4 A2g→ 4 T1g and to 4 A2g→ 2 A1g transition, respectively [1][2][3][4][33][34][35][36][37]. Actually, Cr 6+ is optically inactive since it has 3d 0 configuration, but the charge transfer taking place between O and Cr ions leads to the optically active Cr 5+ (3d 1 2p 5 ) state [1][2][3][38][39][40][41]. The intensity of Cr 6+ peaks clearly gains more intensity with Cr-doping, until a saturation in the UV region is achieved for the x = 0.5 sample.…”

“…Colored glasses acquired a lot of interest in commercial business as they are favored in home decoration and many other technological applications. Optical transitions between energy split d and f levels in transition metals (TM) and rare earth ions, respectively, are the main origin for color effects [1][2][3][4][5][6][7][8][9][10]. For precise and controlled tunability of glasses color, for example, it is appealing to search for suitable glass hosts capable of accommodating varies concentrations of TM ions.…”