Band gap, CIE and trap depth parameters of rare earth molybdate phosphors for optoelectronic applications

Abstract

This paper reports on the comparative investigation of optical, luminescence and dielectric properties of Tb doped lanthanum and gadolinium molybdate phosphors. The crystal structures of the prepared phosphors were identified from XRD studies. The emission spectra of both the phosphors show the most intense peak at 545 nm due to 5D4 → 7F5 transition. The optical absorption and diffuse reflectance spectra of both the phosphors show the main peak at 210 nm due to the band gap. Thermoluminescence studies were carried out after irradiating the phosphors by γ-rays. Trap depth associated with different trap levels was calculated from thermoluminescence data using various glow curve analysis techniques. The dielectric properties such as permittivity and dielectric loss were studied as a function of frequency.