SrLaNaTeO6:Eu3+ red-emitting phosphors with high luminescence efficiency and high thermal stability for high CRI white LEDs

A novel single-phase trivalent europium activated red-emitting SrLaNaTeO₆ phosphor was first synthesized in a process of traditional high-temperature solid-state. The phase purity, morphology, and spectroscopy of the prepared phosphor were analyzed. Under 395 nm excitation, the photoluminescence (PL) spectra of the SrLaNaTeO₆:Eu³⁺ products mainly contained five dominant sharp peaks. The intense red emission peak at 615 nm was the typical ⁵D₀→⁷F₂ electric dipole transition of Eu³⁺. The optimum product of high quenching concentration was the SrLaNaTeO₆:0.90Eu³⁺, which reached a high internal quantum efficiency (IQE) of 90.6%. The SrLaNaTeO₆:0.90Eu³⁺ was estimated to have R_c of 6.57 Å and possessed high color purity of 100.0%. The phosphors exhibited excellent thermal stability and high activation energy (E_a = 0.29 eV). The prepared white light-emitting diode (WLED) had a high color rendering index (CRI) R_a of 92 and a low correlated color temperature (CCT) of 5008 K. In conclusion, the phosphors have potential as red components for WLEDs.