Temperature-responsive insights: Investigating Eu³⁺ and Dy³⁺ activated yttrium calcium oxyborate phosphors for...

An investigation into the luminescent behavior of YCOB (Yttrium Calcium Oxyborate) doped with Eu³⁺ and Dy³⁺ ions, synthesized via the combustion method, is presented. The study, employing X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS) analyses, confirms the structural integrity and purity of the synthesized nanophosphors. An XRD pattern exhibiting distinct crystalline peaks indicates that the dopant ions were successfully integrated into the YCOB lattice. The photoluminescence (PL) response of YCOB with Eu³⁺ and Dy³⁺ ions is thoroughly examined, uncovering distinct excitation and emission spectra. In the case of Eu³⁺ doping, excitation spectra reveal a significant charge transfer (CT) band at 254 nm, indicative of electron transfer between oxygen and europium ions. This CT transition enhances our understanding of the excitation behavior, with the dominant and Laporte-forbidden ⁵D₀ → ⁷F₂ transition. Characteristic peaks at 345 nm in the excitation spectra efficiently stimulate YCOB:Dy³⁺ when Dy³⁺ is used as a dopant. The primary emission peak at 585 nm corresponds to the hypersensitive electric dipole transition ⁴F_9/2-⁶H_13/2. Concentration quenching phenomena are observed, with a maximum Eu³⁺ concentration of 7 wt % attributed to the dipole-quadrupole interaction. Dy³⁺ doping, with a maximum concentration of 2 wt % primarily shows multipolar interactions, especially dipole-dipole interactions. The study extends to CIE chromaticity analysis, emphasizing Eu³⁺ doping's suitability for white light-emitting diode (WLED) applications and ensuring color stability. Conversely, varying Dy³⁺ concentrations do not yield consistent chromaticity coordinates. These findings have significant implications for the development of advanced phosphor materials across diverse applications, offering a roadmap for optimizing their optical performance.