Photoluminescence properties of red phosphor Gd₃PO ₇:Eu³⁺ for UV-pumped light-emitting diodes

A red-emitting Gd₃PO₇:5% Eu³⁺ phosphor is reported. Through transitions of 5d→ 4f (⁷F₁ and ⁷F₂) in Eu³⁺, the phosphor shows a bright red emission under ultraviolet (UV) light excitation. The emission intensity at 615 nm corresponding to ⁵D₀→⁷F₂ transition of Eu³⁺ ion depending on irradiation time under 394 nm excitation increases firstly and then small reduces. After 20 min for UV-light irradiation, it decreases by about 0.5% suggesting that the photostability of the red phosphor Gd₃PO₇:Eu³⁺ is excellent. Under 325 nm excitation, the emission intensities grow rapidly as the temperature increases from 75 K to 285 K and then it keeps on growing slowly until 475 K, revealing the excellent thermostability of the red phosphor Gd ₃PO₇:Eu³⁺. Decay time and time-resolved luminescence measurements have also been studied. All the results reveal that Gd₃PO₇:Eu³⁺ is a promising red-emitting phosphor for UV LED applications.