Insights into the structural and optical properties of Tb3+ substituted Y2Mo4O15

Y2Mo4O15 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) were successfully synthesized using citrate nitrate combustion method. The characterization techniques used in the present study involves X-ray Diffraction, Raman and FTIR spectroscopy, transmission electron microscopy, UV-Visible spectroscopy and photoluminescence spectroscopy. Structural analysis concludes that the compound crystallizes in monoclinic phase with space group P2(1)/c as confirmed through Rietveld refinement. Diffuse reflectance spectra show a high absorption in the wavelength range 250 - 400 nm and the band gap energy values are evaluated. Photoluminescence spectra show an intense green emission at 545 nm and luminescence quenching of Y2Mo4O15 occurs beyond the concentration, x = 0.4. The critical distance evaluated using Blasse's expression is 9.24 & Aring; and dipole-dipole interaction exists between the Tb(3+)ions which is confirmed through Dexter theory. The optimized nanophosphor has internal and external quantum yields equal to 11.01 % and 9.91 %, respectively, and has a decay time of 0.101 ms. These results strongly suggest that the prepared nanophosphor can be used as a green phosphor in pcLEDs.