Quantum efficiency and energy transfer processes in rare-earth doped borate glass for solid-state lighting

• DOI: 10.1016/j.jlumin.2015.07.032
• Publication Date: 2015-08-06T21:28:38Z
• Authors: Franziska Steudel; Sebastian Loos; Bernd Ahrens; Stefan Schweizer
• Keywords: Quantum Efficiency; Quantum yield; Solid-State Lighting

Abstract Sm 3+ , Eu 3+ and Tb 3+ doped borate glass is investigated for its potential as light converting phosphor for solid-state lighting applications. Concentration-dependent luminescence, quantum efficiency and radiative lifetimes are analysed. The luminescence quantum efficiency exceeds values of more than 80%. Cross-relaxation processes in the single-doped glasses result in luminescence quenching for Sm 3+ with increasing doping level, whereas for Eu 3+ and Tb 3+ an increase is observed. In Sm 3+ /Eu 3+ and Tb 3+ /Eu 3+ double-doped glass the energy transfer processes between the rare-earth ions are investigated in detail. The colour coordinate of the Tb 3+ /Eu 3+ double-doped glass can be shifted from the green to the red spectral range by changing the Tb 3+ -to-Eu 3+ ratio in favour of Eu 3+ . In addition, double doping allows for a change in colour coordinate by using different excitation wavelengths.