XRD Spectral Measurements Research Articles

Visible red, NIR and Mid-IR emission studies of Ho3+ doped Zinc Alumino Bismuth Borate glasses

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Holmium were prepared by conventional melt quenching technique. The glassy nature of these glasses has been confirmed through the XRD spectral measurements. The FTIR spectra recorded for undoped glass revealed the information related to the functional groups involved in the host glass. Optical absorption, excitation and photoluminescence spectra of these glasses have been recorded at room temperature. The Judd–Ofelt theory has been applied successfully to characterize the absorption spectra of the ZnAlBiB glasses. From this theory various radiative properties such as radiative transition probability (AR), radiative lifetimes (τR), branching ratios (βR) and spectroscopic quality factor (χ) for the prominent emission levels 5F5→5I7, 5F5→5I8 and 5I7→5I8 have been evaluated. The photoluminescence spectra revealed the quenching of luminescence intensity beyond 1.0mol% of Ho3+ ion concentration in ZnAlBiB glasses. To investigate the lasing potentiality of 5F5→5I7, 5F5→5I8 and 5I7→5I8 transitions, the effective band width (Δλp) and the stimulated emission cross-section (σse) were determined. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for visible red laser emission in principle.

Reddish-orange emission from Pr3+ doped zinc alumino bismuth borate glasses

Praseodymium doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by melt quenching technique and characterized by optical absorption and emission studies. The glassy nature of these glasses has been confirmed through XRD spectral measurements. From the absorption spectra, the Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6) and other radiative properties like transition probability (AR), radiative lifetimes (τR) and branching ratios (βR) have been evaluated. Emission spectra were measured for different concentrations of Pr3+ ions doped glasses by exciting the glasses at 445nm. The intensity of Pr3+ emission spectra increases from 0.1 to 1mol% and beyond 1mol% concentration quenching is observed. The suitable concentration of Pr3+ ions in ZnAlBiB glasses to act as a good lasing material at reddish-orange wavelength (604nm) region has been discussed by measuring the emission cross-sections for the intense emission transition 1D2→3H4. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for reddish-orange emission. From the measured emission cross-sections and CIE chromaticity co-ordinates, it was found that 1mol% of Pr3+ is aptly suitable for the development of visible reddish-orange lasers.

Thermal stability and structure of electroactive polyaniline–fluoroboric acid–dodecylhydrogensulfate salt

Oxidation of aniline by emulsion polymerization pathway using benzoyl peroxide oxidant in the presence of fluoroboric acid and sodium lauryl sulfate surfactant leads to incorporation of both acid group as well as surfactant group onto the polyaniline chain as dopants i.e. formation of polyaniline–fluoroboric acid–dodecylhydrogensulfate salt (PANI–HBF 4–DHS). Amount of dopants such as fluoroboric acid (HBF 4), dodecylhydrogensulfate (DHS) and water present in the PANI–HBF 4–DHS was found out for the first time. Electrochemical activity and rheological stability of the polymer were determined. Thermal stability of PANI–HBF 4–DHS was determined by subjecting the polyaniline salt in macroscale at four different temperatures (100, 150, 200 and 250 °C). Structure, composition and thermal stability of polyaniline salt were determined by chemical analysis, conductivity, IR, UV/vis, XRD spectral measurements from the heat treated samples. Polyaniline salt contains 8.3 wt% water, 22.4 wt% HBF 4 and 15.4 wt% DHS at ambient temperature. Upon vacuum, polyaniline salt loses 4.7 wt% water and on heating the sample at 100 °C it loses the remaining 3.6 wt% water. On further heating polyaniline salt loses its dopants and at 250 °C it loses both the dopants almost completely. Polyaniline salt on heating undergoes cross-linking even at 100 °C and however, conductivity (3 × 10 −2 S/cm) of polyaniline salt was found to remain almost the same up to 150 °C.