Structural, thermal, optical and luminescence properties of Dy3+ ions doped Zinc Potassium Alumino Borate glasses for optoelectronics applications

Abstract

Zinc Potassium Alumino Borate (ZnKAlB) glasses doped with dysprosium (Dy3+) ions of different concentrations were synthesized through the process of melt quenching which is commonly used in solid-state lighting (SSL) and laser systems, to comprehend their viability. This article evaluates and analyzes the physical, structural, thermal and optical properties of Dy3+ ions doped glasses by X-ray diffraction (XRD), Infrared Fourier Transform (FT-IR), differential scanning calorimetry (DSC), UV absorption and photoluminescence (PL) spectra to explain their utilization in optoelectronic devices such as lasers and white light-emitting diodes (w-LEDs). The physical parameters viz. density, refractive index, inter-ionic distance, molar volume, polaron radius, field strength, optical electronegativity, dielectric constant, reflection loss and metallization were computed by following the expressions reported in the literature. Glasses are non-crystalline materials and the non-crystallinity of an un-doped Zinc Potassium Alumino Borate glass was proven by the absence of high-pitched peaks in the XRD spectra. FT-IR spectroscopy was used to identify the presence of different functional groups and their bond nature in Dy3+ ions doped ZnKAlB glasses. The transition temperature (Tg), melting temperature (Tm) and thermal stability was calculated by monitoring DSC thermograms of all glasses. Further, the bonding parameters (δ) and nephelauxetic ratio (β) were estimated to explore the bonding nature of Dy3+ ions in its neighborhoods by using UV-absorption data. The optical direct-indirect band gap energy (Eopt) and Urbach's energy (∆E) were enumerated from the absorption spectrum to elaborate electrical properties of as-prepared glasses. Judd-Ofelt theory was employed to find oscillator strengths from absorption spectra and for further calculation of radiative parameters such as the radiative lifetimes (τR), radiative transition probability (AR), total radiative transition probability (AT) and branching ratio (βR) to understand the quantum efficiency (η). Furthermore, the colorimetric parameters such as correlated color temperature (CCT), CIE coordinates and yellow to blue (Y/B) ratio were estimated from the PL emission data. The multipole-multipole interaction was confirmed by Dexter approximation to explain concentration quenching. This work primarily explains the essential features of borate glasses with Dy3+ ions doping to explain their potential use in tricolor w-LEDs and lasers.