Emission properties of Zinc Gallate nanophosphors

Abstract

Nano-sized ZnGa₂O₄, ZnGa₂O₄:Cr and ZnGa₂O₄:Ti phosphors were synthesized by low-temperature combustion method and the luminescent properties were studied in comparison with those from conventional solid-state reaction. The combustion reaction resulted in a single-phase spinel structure and the particles were 5–10 nm in size. Of all samples, undoped nano ZnGa₂O₄ exhibited an intrinsic blue emission and Ti-doped nano ZnGa₂O₄ had a tendency of white emission whereas Cr-doped nano ZnGa₂O₄ showed red emissions. Titanium ions in spinel structure was found to exist as in Ti³⁺ and Ti⁴⁺, but favouring trivalent state. The oxidation state of Cr ions was confirmed as 3⁺ in nano ZnGa₂O₄.