White solid-state lighting potential of Dysprosium-doped lithium strontium zinc borate glass

Solid-state photo luminescent materials for efficient production of white light with properties that resolve current challenges such as red and green re-absorption of blue light, halo effect, and removal of epoxy resin are much needed. As a result, borate-based glasses were prepared using standard melt-quenching techniques with a molar composition of 20Li₂CO₃–5SrO–5ZnO–(70-x )B₂O₃–xDy₂O₃ (0 ≤ x ≤ 1.25). Prepared samples were characterised to identify their white light-emitting ability. The XRD analysis of the glasses revealed a large hump in the range 2θ without any diffraction peak which indicated that the samples were glasses. The Ftir absorption spectra indicated the existence of borate functional groups, while the EDX study confirmed the incorporation of primary trace elements into glass systems. The Dta thermo gram analysis of the samples showed excellent thermal stability against crystallisation of 114°C and the Hruby parameter of 2.44. The optical absorption spectra of the glasses demonstrated twelve bands associated with dysprosium ion transitions. The emission spectra measured at an excitation wavelength of 350 nm displayed strong blue and yellow peaks and weak red peaks. The peaks are associated with transitions from 4F_9/2 to ⁶H_15/2, ⁶H_13/2, and ⁶H_11/2. The 1931 CIE colour map showed coordinates in the cool white light area with a difference of about 1−10 %. The evaluated CCT values were above 5300 K and the colour purity range was 4.8−11.6 %. Such disclosure can contribute to the efficient generation of white light based on glass. (author)