New physical insight into crystal structure, luminescence and optical properties of YPO4:Dy3+∖Eu3+∖Tb3+ single-phase white-light-emitting phosphors

A novel single-phase white-light-emitting YPO 4 phosphor, single and co-doped with Dy 3+ /Eu 3+ , aiming at UV-pumping in white-light-emitting diodes (WLEDs) which exhibits an outstanding optical performance, was successfully produced. The crystal structure, the morphology, the electronic band structure , the electronic configuration, and the bond length of the prepared phosphors were thoroughly investigated, both experimentally and by computational methodology. The results showed that the host lattice provides various surrounding environments to the Eu 3+ activators is a results of Eu 3+ single and Dy 3+ /Eu 3+ co – doped YPO 4 phosphors. Under ultra-violet (UV) excitation (353 nm), the prepared tetragonal phase YPO 4 :Dy 3+ phosphors emitted a bluish-white-light because it has peaks of similar intensity in the blue and the yellow spectral region . The emission spectrum can be tuned from bluish white to green/yellow/red and warm white by adjusting the concentration of Tb 3+ /Eu 3+ dopants . A high photoluminescence quantum yield (PLQYs) 68.55% was achieved. It was observed that the tetragonal YPO 4 :Tb 3+ /Dy 3+ /Eu 3+ phosphors emit-white-light which covers the whole visible region, and have good thermal stability from 20 to 200 °C. Finally, a WLED was fabricated by using a UV LED (365 nm) chip coated with the optimized YPO 4 :Tb 3+ /Dy 3+ /Eu 3+ single-phase phosphor, demonstrating an excellent white-light emission with a high CRI value (R a  = 92) and a low CCT value (T c  = 2497 K). Hence, the produced material is a promising candidate for UV-pumped single-phase phosphor-converted WLEDs.