An investigation about the luminescence mechanism of SrGa₂O₄:Eu³⁺ showing no detectable energy transfer from the host to the dopant ions

Un-doped SrGa₂O₄ and a series of Eu³⁺ ions doped SrGa₂O₄ were synthesized by conventional solid state reactions. The X-ray diffraction patterns, photoluminescence excitation and photoluminescence spectra, diffuse reflection spectra of these samples were recorded and analyzed. Un-doped SrGa₂O₄ can emit blue-violet light in a broad band peaking at 407 nm under the excitation at 234 and 252 nm. Eu³⁺ ions doped SrGa₂O₄ phosphors exhibit red emission under the excitation at 274 nm. However, there is no detectable energy transfer from the host to doped Eu³⁺ ions. The further luminescence mechanism and reasons for the absence of energy transfer from the host to doped Eu³⁺ ions are discussed in detail. A novel mechanism about the luminescence of gallium compounds is proposed based on our experimental results. An energy level diagram is proposed to illustrate the luminescence mechanism of gallium compounds and reasons for the absence of energy transfer from the host to doped Eu³⁺ ions.