Understanding energy transfer in Ce doped Li6Gd(BO3)3: A study of millisecond decay kinetics in 77–300K range

Abstract: Large size, transparent and crack-free single crystals of pure and 0.1mol% Ce doped Li6Gd(BO3)3 have been grown using the Czochralski technique. The photoluminescence and decay kinetics in millisecond range were investigated in the 77–300K temperature range. In the case of Ce doped single crystals a broad emission band at 400nm corresponding to 5d→4f transitions of Ce3+ centers has been observed near room temperature. This emission band splits into two peaks at 386nm and 414nm below 200K. The temperature dependence of Ce3+ emission corresponding to excitation bands at 312 and 345nm were studied. It was observed that for an excitation at 345nm (corresponding to the Ce3+ ions alone) the emission intensity decreases with increasing temperatures while it remains constant for the excitation of Ce3+ at 312nm that coincides with the Gd3+ energy level at the same wavelength. This suggests the participation of a temperature dependent energy transfer mechanism between Gd3+ and Ce3+ ions in the Li6Gd(BO3)3 matrix. The mechanism has been explained by studying the temperature dependence of Gd3+ emission at 312nm in the doped and undoped crystals. [Copyright &y& Elsevier]