Optical investigation of Dy3+/ Eu3+ co-activated K2NaAlF6 fluorophosphor for color tunable lighting system: Structural analysis and warm light generation

Abstract

Nowadays, research is mostly focused on developing luminous materials. Specifically, compounds based on inorganic phosphorus have found widespread use in a variety of applications, like radiation dosimetry, field emission displays (FEDs), cathode ray tubes (CRTs), lamp industries, and white light emitting diodes (WLEDs). In order to achieve white light emission, we successfully synthesized single-host K₂NaAlF₆ co-doped with Dy³⁺/Eu³⁺ in this study utilizing the pechini sol-gel approach. Under UV light, the synthesized samples' luminescence characteristics were examined. XRD analysis verified K₂NaAlF₆'s phase purity. The phosphor materials have a tendency to aggregate, as seen by SEM pictures. The K₂NaAlF₆:Dy³⁺ doped phosphors showed good excitation at 349 nm in photoluminescence (PL) experiments, with strong emission bands at 489 nm (blue) and 576 nm (yellow). Strong orange emissions were seen for K₂NaAlF₆: Eu³⁺ doped phosphors at 595 nm and 614 nm, which correspond to the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions in Eu³⁺ ions. When these rare earths were co-doped, intense red, yellow, and blue emissions were produced. The Commission Internationale de l'Eclairage (CIE) coordinates were used to calculate the colour characteristics of the luminous produced samples. Consequently, these results imply that Dy³⁺/Eu³⁺ co-doped K₂NaAlF₆ phosphors, when stimulated by UV LEDs, could be appropriate for creating reddish-orange and warm white lighting systems.