Energy transfer and color tunability in high-thermal-stability Dy3+/Tb3+ co-doped K3YF6 transparent oxyfluoride glass ceramics

The production process and comprehensive analysis of the co-doping of Dy ³⁺ and Tb ³⁺ in K ₃YF ₆ oxyfluoride glass-ceramics (GCs) are delved. The primary focus is on investigating the luminescent properties and energy transfer (ET) mechanisms within these systems. The embedding of well-formed K ₃YF ₆ nanocrystals within the matrix was verified through detailed analyses using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fine-tuning the Tb ³⁺ concentration facilitated the achievement of tunable emission, ranging from a subtle yellow to a yellowish green hue, demonstrating the remarkable flexibility in color manipulation. Fluorescence analysis unmistakably demonstrates the occurrence of energy transfer occurring between Dy ³⁺ and Tb ³⁺ ions, attaining a peak energy transfer efficiency of 51.33 %. Additional analysis applying Dexter`s energy transfer formula affirms that the fundamental mechanism of energy transfer between Dy ³⁺ and Tb ³⁺ ions is dipole-dipole interaction. The K ₃YF ₆ glass ceramics (GCs) incorporating Dy ³⁺/Tb ³⁺ nanocrystals exhibit a remarkable thermal stability, retaining 89.07 % of their original relative emission intensity at 423 K when stimulated by 350 nm light. These findings indicate that Dy ³⁺/Tb ³⁺ co-doped K ₃YF ₆ GCs hold significant potential in solid state lighting, positioning them as a candidate for future lighting.