Tuneable colour flexibility in Dy3+&Eu3+ co-doped lithium fluoride bismuth borate glass system for solid state lighting applications

Abstract

Rare Earth ion (Dy3+and Eu3+) co-doped glasses with composition xEu2O3·(1 − x) Dy2O3·30LiF·10Bi2O3·60B2O3 were synthesized by melt quench technique. Density and molar volume measurements were performed to examine the Physical properties. FTIR exploration of the prepared glasses enlightened the presence of traditional bismuth and borate groups. Prepared glasses were thermally stable and optical band gap was found near 2.72 eV. Optical studies evidenced ionic nature of Dysprosium ions and covalent nature of Europium ions in the glass matrix. Using Photoluminescence emission spectra parameters like CIE coordinates, Correlated Colour Temperature, Colour Rendering Index and colour purity were calculated for different excitation wavelengths. Composition DELBB(x = 0.2) has been observed to be the best potential candidate for white LEDs with CIE coordinates (0.329, 0.342), improved CRI and low colour purity per cent. Electrical properties: DC and AC conductivity, Dielectric measurements, Modulus analysis and Nyquist plots were also studied with the variation of temperature.