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Structural and luminescence properties of Dy3+-doped alkali fluoroborophosphate glasses for white LEDs applications
摘要： A new series of Dy3+-doped alkali fluoroborophosphate glasses were prepared by conventional melt quenching technique, and their structural and optical properties were investigated through XRD, FTIR, optical absorption, luminescence and decay measurements. The X-ray diffraction pattern reveals the amorphous nature of the prepared glasses. The fundamental stretching vibrations of various borate (BO3 and BO4) and phosphate (PO4) networks were identified through the FTIR analysis. The nature of the metal–ligand bonding and the electronic band structure has been investigated using the absorption spectra. The Judd–Ofelt (JO) intensity parameters (X2, X4 and X6) were evaluated, and the experimental oscillator strength values were also calculated. Using the JO intensity parameters, radiative properties like radiative transition probability (A), stimulated emission cross section (rE) and branching ratios (bR) for the emission transitions of the Dy3+ ions have been calculated. The luminescence spectra exhibit two visible bands of 4F9/2 → 6H15/2 (Blue) and 4F9/2 → 6H13/2 (Yellow). The decay time of the 4F9/2 level has been measured from the decay profiles and compared with the calculated lifetimes. The yellow-to-blue (Y/B) ratios and color coordinates have been calculated from the luminescence spectra and can be considered for white light emitting diodes applications.
关键词： Absorption,CIE diagram,Melt quenching technique,Rare-earth,Photoluminescence
更新于2025-09-11 14:15:04
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Optical characterisation of amorphous Se–Te–Sn thin films
摘要： Optical characterization of Sn doped Se–Te thin films has been carried out. The characterization has been carried out using transmission spectra in range 500–2500 nm. Bulk samples were prepared using melt quenching technique and thin films were deposited using thermal evaporation. XRD analysis was used to confirm the amorphous nature of prepared samples. Optical constants such as refractive index and extinction coefficient have been determined using Swanepoel’s method. Variation of refractive index with wavelength has been analysed using single effective oscillator model. Optical band gap of the deposited films was calculated using Tauc plots. The observed properties have been explained using the chemical bond approach.
关键词： Tauc plots,Swanepoel’s method,melt quenching technique,thermal evaporation,Se–Te–Sn thin films,Optical characterization
更新于2025-09-09 09:28:46