Hydrothermal Synthesis of Zn₂GeO₄ and Mn²⁺ Doped Zn₂GeO₄ (ZGO) Nanoparticles with Controlled Luminescent Properties

Abstract

This paper reports the first attempt to synthesize un-doped spherical Zn₂GeO₄ stoichiometry and Mn²⁺ doped Zn₂GeO₄ nanoparticles to achieve a controlled luminescence, particularly, by changing Zn:Ge ratio and Mn²⁺ concentration during the hydrothermal process. The morphology of the un-doped Zn₂GeO₄ nanoparticle was depended on the Zn:Ge ratio that was observed to have a nanorod structure to sphere-like morphology; however, the morphology of Mn²⁺ doped Zn₂GeO₄ was not changed as the use of Mn²⁺ as a dopant. The un-doped Zn₂GeO₄ showed a broad emission at ∼510 nm and its intensities were functioned of Zn:Ge ratio. On the other hand, the Mn²⁺ doped Zn₂GeO₄ showed emission peaks at ∼532 nm and they can be attributed to the ⁴T₁ → ⁶A₁ transition in Mn²⁺ ions doped in Zn₂GeO₄. These results suggest the effectiveness use of Zn:Ge ratio and Mn²⁺ doped Zn₂GeO₄ in tuning the luminescence of Zn₂GeO₄ nanoparticles, which are of potential applications as phosphors in wide range of engineered fields, in particular optoelectronics.

Fig. 7 (A) UV-VIS spectrum of ZGO and ZGO:Mn²⁺, (B) Schematic explaining their PL spectra and host to Mn²⁺ energy transfer (ET) in ZGO.