Observation of "cool daylight" white light emission from Eu and Tb co-doped SrMoO₄ nano ceramics

Graphical abstract: - Highlights: • Synthesis of undoped and Eu and Tb-doped and Eu–Tb co-doped Strontium Molybdate (SMO) by co-precipitation method. • Characterization of the samples by XRD, SEM and DLS for particle size. • Observation of orange-red emission and blue-green emission from the Eu-doped and Tb-doped samples, respectively. • Optimization of the dopant ion concentration for white light emission from the co-doped sample. • Observation of cool day light white light emission with CCT 6863 K from the co-doped system (Eu-0.5 mol% and Tb-1 mol%). - Abstract: Nano ceramics of undoped and Eu and Tb-doped strontium molybdate (SMO) were synthesized via co-precipitation route and characterized by XRD, SEM and DLS techniques. It was observed that the average particle size for the samples was 90 nm. A bluish emission attributed to the tetrahedral molybdate moiety was observed for the undoped system. The single-doped sample Eu³⁺:SMO gave orange-red emission, whereas the Tb³⁺:SMO sample showed blue-green emission. From the emission data, the site symmetry of the ions was estimated. Based on the emission data of single-doped samples, the co-dopant ions concentrations were tuned to extract white light emission from the system. It was observed that when doped with 0.5 mol% Eu³⁺ and 1 mol% Tb³⁺ and excited with 230 nm, the system gave a 'cool day light' white light emission with a correlated color temperature (CCT) 6863 K.