Spectroscopic characteristics of Dy3+ impurities–doped borate-based glasses: Judd–Ofelt calculation

Abstract

Using the melt-quenching method, Dy3+-doped lithium-strontium-zinc-borate glasses of composition 20Li2O–5SrO–5ZnO–(70-x)B2O3–xDy2O3 (0≤x≤1.25 mol%) were prepared and characterised using various tools. The Dy3+ contents dependent spectroscopic traits of these glasses were determined to identify their white light-emitting potential. The Judd-Ofelt (JO) evaluation was made to validate the experimentally measured optical properties. The XRD patterns of the as-quenched samples revealed their glassy nature and the FTIR spectra exhibited the presence of BO3 and BO4 functional groups. The absorption spectra of the samples showed twelve characteristic bands of Dy3+ wherein the hypersensitive one occurred at 1270 nm. The JO intensity parameters revealed a changing trend from Ω2>Ω4>Ω6 to Ω2>Ω6>Ω4, indicating the effectiveness of Dy3+ doping. The photoluminescence emission spectra of the glasses exhibited the three significant peaks (intense blue, intense yellow and weak red) with concentration quenching beyond 1 mol% of Dy3+. The radiative parameters of 4F9/2 → 6H13/2 transition disclosed the highest branching ratio (≥85%), radiative transition probability of 504–1711 s−1, stimulated emission cross-section from 28.70×10−22−19.01×10−22cm2, optical bandwidth of 1.34×10−20−4.63×10−20cm3 and optical gain of ~ 14.5×10−25cm2s, suggesting optical energy harnessing potential of the proposed glass composition which are useful in low threshold and efficient lasers and amplifiers design. The quantum efficiency of the glasses was ranged from 34–84%. The 1931 CIE analyses of the samples disclosed the colour coordinates appearance very close to the pure white (within 1–10%) with colour purities ranged from 11.6 to 4.8%, and the estimated values of CCT were above 5300 K, indicating their potency for the cool white light emission.