Color tunable emission and temperature dependent photoluminescence properties of Eu3+ co-doped Gd2Zr2O7:Dy3+ phosphors

The present study focuses on the color-tunable properties through energy transfer mechanism of single-phase Gd2Zr2O7:Dy3+, Eu3+ phosphors prepared by hydrothermal method. For this intent, we have taken Eu3+ ion as an activator in 2 mol% Dy3+ doped Gd2Zr2O7 (GZO) phosphors. The formation of the defect fluorite phase of the prepared phosphors was confirmed from XRD diffraction pattern. UV-Vis diffuse reflectance spectra were utilized to estimate the optical bandgap of the materials. The characteristic photoluminescence (PL) properties related to the electronic transition of both Dy3+ and Eu3+ ions were observed under direct excitation of Dy3+ ions. In addition, the effect of Eu3+ concentration on the luminescence properties of GZO: 0.02Dy(3+) was studied. The average lifetimes of both the excited states, F-4(9/2) of Dy3+ and D-5(0) of Eu3+ were estimated. PL and lifetime measurements illustrate that an energy transfer is possible between sensitizers and activators ions and mechanism involving the energy transfer process has been discussed. Thermal stability was also examined from temperature dependent PL spectra within the temperature range 80 K-450 K. As we increase the Eu3+ concentration within GZO: 0.02Dy(3+) phosphors, the CIE co-ordinates shift toward the warm white region from the natural white region and finally shift toward the orange pink region. All the experimental results indicate that the proposed phosphors can be a possible choice for colour converting materials in solid state lighting applications.