Tm/Tb/Eu triple-doped lithium aluminoborate glass for white light generation

The aim was to design a multi-chromatic phosphor based on the colour mixing principle, whereby white light can be produced from an appropriate mixture of blue, green, and red emissions by a single phosphor. In this perspective, Tm2O3, Tb4O7, and Eu2O3 were simultaneously doped in single host glass matrix. A series of Tm2O3 single- as well as Tm/Tb/Eu triple-doped glasses were synthesised. The photoluminescence behaviour and luminescence quenching were investigated for Tm2O3 single-doped glasses. Keeping Tm2O3 constant at the saturation concentration in the Tm/Tb/Eu triple-doped glasses and varying the doping ratio of the two other lanthanides (Tb4O7 and Eu2O3) in the host glass allow to some extent the control of the spectral composition and consequently the generation of tunable colour impressions. The latter can also be adjusted by keeping the concentration ratio of the three lanthanides constant and varying the excitation wavelength. Upon 358-nm excitation of the Tm/Tb/Eu triple-doped glasses, white light emission is achieved and the corresponding correlated colour temperatures are also determined. The different energy transfers occurring in between the three lanthanides are investigated and possible energy transfer routes are proposed.