Tunable and white emission from ZnO: Tb³⁺ nanophosphors for solid state lighting applications

Terbium doped Zinc oxide (ZnO:Tb³⁺) nano-phosphors (NPr) with a hexagonal wurtzite structure were synthesised by a solution combustion method. X-ray photoelectron spectroscopy confirmed the formation of different kind of defects for the undoped and lower Tb doping concentrations and the formation of Tb₂O₃ at higher doping concentrations. A broadband orange-red emission ranging from 500 to 850nm was obtained from the undoped ZnO while white light emission was observed from ZnO doped with 5mol% of Tb. The colour of the emission of the ZnO:Tb3⁺ NPr was tuned by varying the concentrations of Tb³⁺ in the ZnO host. The ZnO:Tb³⁺ NPr have potential applications in solid state lighting.