Reddish-Orange Light Emission in Eu Doped and Dy/Eu Codoped lithium Tetraborate Glasses for Solid-State Lighting Devices.

The spectroscopic analysis of singly doped Eu and codoped Dy/Eu lithium tetraborate (LiTeBo) glasses has been carried out to explore the effects of various alkaline earth and alkali components. The analysis involved techniques such as XRD, SEM, FTIR, optical absorption, photoluminescence, and decay spectral profiles. From the optical absorption spectra of Eu doped glasses, the bonding properties, optical energy band gaps, nephlauxetic ratios, and Urbach energies were obtained. From the emission spectra, color coordinates, correlated color temperatures, and color purities were obtained. The occurrence of energy transfer from Dy to Eu is confirmed across all glass samples by analyzing the emission spectra, assessing the overlap in the spectral regions between the Eu excitation and Dy emission, and evaluating the fluorescence decay curves. The emission spectra of glasses codoped with Dy/Eu ions provided excitation wavelengths, 350, 364, 387 and 394 nm. From the emission transitions, the transitions originated from F to H, H of Dy ion, and from D to F of Eu ion indicate the creation of reddish-orange light. The CIE chromaticity coordinates shift from reddish to reddish-orange color along with the excitation wavelengths 350, 364, 387 and 394 nm.