White-light generation in Sr2SiO4 : Eu2+, Ce3+ under near-UV excitation - A novel phosphor for solid-state lighting

White-light emission is generated by combining blue and blue green to yellow emissions of Ce3+ and Eu2+, respectively, in a single host lattice of Sr2SiO4. The excitation is in the near-UV region (350-370 nm). The role of concentration of Eu2+ on the photoluminescence emission intensity in Sr2-xEuxSiO4 [x = 0.0025, 0.005, 0.0075, and 0.01] is studied, and it is found that the critical concentration is 0.0025 mol. Energy migration over Eu2+ sites occurs, resulting in concentration quenching. Ce3+ exhibits a high absorption in the near-UV region. Energy transfer from Ce3+ to Eu2+ occurs in Sr2SiO4: Eu2+, Ce3+. Optimization of concentration of Eu2+ to produce white light in Sr1.98-xEuxCe0.01Li0.01SiO4 shows that the optimum concentrations of Ce3+ and Eu2+ are 0.01 and 0.0025 mols, respectively. Partial energy transfer from Ce3+ to Eu2+ is responsible for the white-light generation. The results reveal that Sr2SiO4: Eu2+, Ce3+ is an efficient single host lattice phosphor for solid-state lighting technology using UV light-emitting diode (LED) to generate white light. (c) 2005 The Electrochemical Society.