Effects of Mn Doping on the Optical Properties of Zn2GeO4 Phosphor Prepared Through Co-Precipitation

Abstract

Zn₂GeO₄ (ZGO) phosphor and Mn-doped ZGO (ZGO:Mn²⁺) phosphor were successfully synthesized through co-precipitation. Results indicated that Zn ions were successfully replaced by Mn ions, and Mn doping led to a lattice contraction. Under UV light excitation, the undoped ZGO exhibited a strong white-bluish emission at 517 nm and weak green emission at 530 nm, both of which were attributed to the native defects in the ZGO host. The near infrared emission (~740 nm) was attributed to the transfer of energy from nonbridging oxygen-hole centers to zinc (Zn_i) and oxygen-vacant state (V_О) in the ZGO host. ZGO:Mn²⁺ emitted a band at ~535 nm which originated from the ⁴ T₁–⁶ A₁ transition of Mn²⁺ ion. These initial findings showed that the luminescence properties in the green and near infrared range of ZGO phosphor can be controlled.