Analysis of the structure and luminescence properties of Zn2 GeO4 :Eu3+ according to Judd-Ofelt theory.

Abstract

The preparation and characteristic of nanorod-like Zn2 GeO4 doped with Eu3+ or zinc germanate (ZGO):xEu3+ (x = 0 ÷ 0.05), which was synthesized using the hydrothermal method, are described. The influence of Eu3+ -doping ions on the structure and the optical properties of ZGO was also investigated. According to the photoluminescence spectra, ZGO:xEu3+ nanophosphors gave a red emission due to the 5 D0 →7 F2 emission of Eu3+ ions. In accordance with Judd-Ofelt theory, the intensity parameters for f-f transitions from the emission and absorption spectrum were determined. At the 5 D0 excited state of Eu3+ , total spontaneous emission probabilities (AR ), lifetimes (τR ), branching ratios (βR ), and quantum efficiency (η) were calculated. The ZGO:xEu3+ (x = 0.02, 0.03, 0.04) phosphor showed the branch ratio β (5 D0 →7 F2 ) > 60%, indicating that the phosphors prepared here have a promising potential as laser light. The sample with a concentration of 0.04Eu3+ achieved the highest quantum efficiency of 84%, suggesting that it has potential light-emitting diode applications.