Publication

Abstract :

The demand for white light emissions from glasses is driven by the urgent need for sustainable, energy-efficient solutions that significantly enhance performance and pave the way for a greener, more efficient future across industries such as lighting, displays and communication. In view of it, herein we present the comprehensive investigation of the structural, optical and luminescence properties of Dy³⁺-doped Li₂O + CaO + B₂O₃ glasses utilizing various analytical techniques, including XRD, FTIR, UV–visible and PL spectroscopic techniques. Additionally, JO analysis is carried out to support the radiative transitions, luminescence emission and energy transfer mechanism in the prepared glasses. It was evidenced that the incorporation of Dy³⁺ ions in the glass matrix played a pivotal role in retaining the amorphous nature and modifying essential optical attributes such as the refractive index, band gap and the intricate interactions of emission bands. The optical absorption spectra of glasses reveal eleven distinct peaks corresponding to electronic transitions from the Dy³⁺ ground state (⁶H_15/2) to various excited states. A slight decrease in  from 3.07 to 3.04 eV was observed with increasing Dy³⁺ concentration. Photoluminescence spectra recorded under excitations at 349, 364, 385 and 452 nm exhibit emission bands around 483 nm, 576 nm and 664 nm, attributed to ⁴F_9/2 → ⁶H_{J (J = 15/2, 13/2, 11/2)} transitions, respectively. Among these, the magnetic dipole transition (⁴F_9/2 → ⁶H_15/2) remains unaffected by the environment, whereas the electric dipole transition (⁴F_9/2 → ⁶H_13/2) is hypersensitive and shows enhanced intensity. Concentration quenching observed in LCBDy₁ is attributed to resonant energy transfer (RET) or cross-relaxation (CRC), leading to non-radiative phonon-assisted energy dissipation. The LCBDy_0.5 glass demonstrates the most efficient luminescence under 349 nm excitation, supported by CIE and Judd–Ofelt (JO) analysis. The JO parameters (Ω₂ > Ω₆ > Ω₄) suggest a high degree of covalency and optimal local symmetry for Dy³⁺ ions within the LCB glass matrix. These modifications yield correlated colour temperatures that traverse the bright white light emission as evidenced from the PL analysis and CIE studies supported by the JO analysis.