Controllable synthesis and morphology-dependent photoluminescence properties of well-defined one-dimensional Zn 2 GeO 4 :Mn 2+ nanostructures

A variety of uniform and well-dispersed one-dimensional Zn2GeO4:Mn2+ phosphors have been synthesized via a facile solvothermal process with H2O/EG as solvent. During the synthesis process, the component of solvent and the addition of PEG surfactant play an important role in determining the structure, particle size, and morphology of the final product. Under ultraviolet light excitation, the pure Zn2GeO4 sample shows bluish-white emission which is attributed to the native defects present in the Zn2GeO4 host. When Zn2+ ions are partially substituted by Mn2+, the as-synthesized Zn2GeO4:Mn2+ samples exhibit intense green emission that corresponds to the d-d transition (4T1→6A1) of Mn2+ ions. The luminescence mechanisms of the Zn2GeO4:Mn2+ samples were investigated in detail by using the CASTEP code based on density functional theory (DFT). It is expected that the as-synthesized Zn2GeO4:Mn2+ phosphors can be potentially applied in lighting, optical displays, and optoelectronic devices.