Tunable white-light emission of Dy3+ or/and Eu3+ co-doped single-phase LiY(PO3)4 phosphors for NUV-WLEDs.

A series of Dy3+ and Dy3+/Eu3+ co-doped LiY(PO 3) 4 phosphors are prepared by sol-gel combustion method, followed by annealing treatment at 700 °C for 10 min. XRD patterns and TEM images show that the LiY 1-m-n Dy m Eu n (PO 3) 4 phosphors are characterized by monoclinic phase and regular short rod or nearly spherical granules. Excited at 363 nm, the Dy3+ single doped LiY(PO 3) 4 phosphors have two intense emission peaks at 482 nm and 574 nm. Its chromaticity coordinate point is centred at (0.305 ± 0.003, 0.33 ± 0.015) and its CCT is higher than 6700 K. By introducing Eu3+ ions to LiY 0.96 Dy 0.04 (PO 3) 4 phosphors, chromaticity coordinate point and CCT of LiY 0.96-n Dy 0.04 Eu n (PO 3) 4 phosphors can be adjusted almost linearly due to energy transfer between Dy3+ ions and Eu3+ ions. The corresponding CCT of 4927–6052 K and chromaticity coordinate point of (0.3334 ± 0.0136, 0.3492 ± 0.0014) can be achieved for LiY 0.96-n Dy 0.04 Eu n (PO 3) 4 (n = 0.03–0.05) phosphors with high luminescence thermal stabilities and energy transfer efficiency of more than 18.99%. These results indicate that Dy3+/Eu3+ co-doped LiY(PO 3) 4 phosphors are expected to be a promising single matrix white emitting phosphors with tunable white-light emission for NUV-WLEDs. Image 1 • LiY(PO 3) 4 :Dy/Eu phosphor can be prepared by sol-gel combustion method. • LiY(PO 3) 4 :Dy/Eu phosphors show a tunable white-light emission. • LiY 0.96-n Dy 0.04 Eu n (PO 3) 4 (n > 0.03) has high ET efficiency (>19%). • LiY(PO 3) 4 :Dy/Eu phosphor has high PL thermal stabilities (83% at 180 °C). • LiY 0.92 Dy 0.04 Eu 0.04 (PO 3) 4 show a CCT of 5398 K and coordinate (0.335, 0.35). [ABSTRACT FROM AUTHOR]