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 YPO4 phosphor, single and co-doped with Dy3+/Eu3+, 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 Eu3+ activators is a results of Eu3+ single and Dy3+/ Eu3+ co - doped YPO4 phosphors. Under ultra-violet (UV) excitation (353 nm), the prepared tetragonal phase YPO4:Dy3+ 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 Tb3+/Eu3+ dopants. A high photoluminescence quantum yield (PLQYs) 68.55% was achieved. It was observed that the tetragonal YPO4:Tb3+/Dy-3(+)/Eu3+ phosphors emit-white-light which covers the whole visible region, and have good thermal stability from 20 to 200 degrees C. Finally, a WLED was fabricated by using a UV LED (365 nm) chip coated with the optimized YPO4:Tb3+/Dy-3(+)/Eu3+ 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. (C) 2019 Elsevier B.V. All rights reserved.