Analysis of the structure and luminescence properties of Zn GeO :Eu according to Judd-Ofelt theory.

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