Luminescence properties and its red shift of blue-emitting phosphor Na3YSi3O9:Ce3+ for UV LED

A series of Na3YSi3O9:Ce3+ phosphors have been synthesized via a conventional high temperature solid-state reaction. Each crystal structure was characterized by X-ray diffraction (XRD) and refined by the Rietveld method. Luminescence properties of Na3YSi3O9:Ce3+ phosphors such as emission red shifts, fluorescence decay curves, thermal stability, and CIE values were systematically investigated. Upon 300 nm excitation, the emission peaks of Na3YSi3O9:Ce3+ phosphors red shift from 385 nm to 415 nm with Ce3+ concentration increasing from 0.002 to 0.11. Moreover, this red-shift phenomenon also occurs with an excitation wavelength from 270 nm to 340 nm as the Ce3+ concentration determined, which has been explained using the centroid shift and crystal field splitting. The quenching concentration of Ce3+ in the host Na3YSi3O9 is determined to be about 3 mol% and the critical distance is calculated to be about 16.623 Aa. The energy dispersion mechanism between Ce3+ ions was verified to be a dipole-dipole interaction. Temperature-dependent luminescence of Na3YSi3O9:0.03Ce3+ from 25 degree C to 250 degree C was evaluated, and the corresponding activation energy Delta E is 0.277 eV. Not only crystal field splitting but also centroid shift plays an important role in the red-shift of the Na3YSi3O9:Ce3+ phosphors, which may contribute to future research in designing novel solid phosphors by modifying composition of the host lattice to affect crystal field splitting and centroid shift, and then adjusting emission wavelengths to match the purposed application.