RESUMEN
This paper reports the effect of incorporation of Yb3+ions on the frequency downconversion luminescence and thermal properties of triply ionised Ho3+doped zinc tellurite (TZ) glasses. The photoluminescence spectra of both the Ho3+/Yb3+doped and codoped glasses have been recorded and observed a green emission band corresponding to the5F4,5S2â5I8(â¼550 nm) transition upon various excitations. In the downconversion (DC) emission process, the back energy transfer (BET) mechanism from Ho3+ions to Yb3+ions has also been explored. The colour emitted in the downconversion process is found to be non-tunable at different excitations. Thus, the Ho3+:TZ glass can be utilised for non-colour tunable optical devices under various UV excitations. Also the glass transition (Tg) and crystallisation (Tc) temperatures have been measured for both the doped and codoped glasses and found to be increased in the codoped glass. The singly Ho3+ions doped TZ glass shows better optical downconversion and glass forming ability.
RESUMEN
A series of six lead-bismuth tellurite glass samples were prepared by using the melt quenching technique. The Physical properties of the samples such as density and molar were studied. The measurements of density were calculated via using Archimedes' principle. XDR technique was used to confirm the amorphous nature of the samples. The optical properties of the samples such as direct and indirect bandgaps were calculated based on the Davis-Mott equation by employing Tauc's method. The disorderliness of the glass system was measured by calculating Urbach energy and steepness. Density and refractive indices results show an increasing trend with increasing PbO concentration. The non-metallic nature of the samples was investigated by using the metallization criterion. Optical basicity and basicity moderating parameters were calculated for each glass sample by using Duffy and Ingram formula. The metallization criterion results of the synthesized glasses are best for nonlinear optical devices.
RESUMEN
On the basis of the higher order perturbation formulas of g factors for a 4d1 group in tetragonally compressed octahedra, the g factors, optical absorption, local structure, and their concentration dependences of pentavalent molybdenum in 40PbO-(10 - x)Y2 O3 -50P2 O5 :xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq , covalent factor N, and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8% to 4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2 O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems.
RESUMEN
A series of glass samples with chemical formula {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1-x(Dy2O3)x where x=0.01, 0.02, 0.03, 0.04 and 0.05M fraction were synthesized through conventional melt-quenching method. The most common way to fabricate a glass material is by fusion of two or more component oxides followed by their quenching. This technique is known as melt-quenching technique. Kaur et al. (2016) [1] highlighted that the melt-quenching method able to enhance the mechanical properties like hardness and flexural strength of the material. The nature of the glass systems is proven to be amorphous based on the XRD pattern. The FTIR spectra of the glass systems confirm the existence of five bands which are assigned for the BO4, BO3, TeO4 and TeO3 vibrational groups. The density of the glass systems is increased with the addition of Dy2O3 while the molar volume is found to be inversely proportional to the density of the proposed glass. The optical properties of the glasses are determined through the absorption spectra obtained from the UV-VIS spectrophotometer. From the absorption spectra, the indirect and direct optical band gaps and the Urbach energy are found to be inversely proportional to each other. As the molar fraction of the Dy2O3 increased, the optical band gaps are observed to increase as opposed to the Urbach energy. For this glass system, the values of refractive index, electronic polarizability, oxide ion polarizability and the optical basicity are found to decrease as the addition of the dysprosium oxide is increased. From the emission spectra, two intense blue and yellow emission bands are observed, which correspond to the 4F9/2â6H15/2 and 4F9/2â6H13/2 transitions of Dy3+ ions respectively. The CIE chromaticity coordinates of the zinc borotellurite glass systems are found to be located in the white light region.