Microwave and ultrasonic radiation-activated synthesis and luminescent properties of nanopowder YVO 4 : Bi 3+ , Eu 3+

Microwave and ultrasonic radiation-activated synthesis of YVO 4 -based phosphors doped with Bi 3+ and Eu 3+ is proposed. XRD and LXRSMA results confirm the incorporation of Bi 3+ and Eu 3+ ions into the YVO 4 crystal lattice. The particles of the obtained powders have a pronounced spherical shape with a predominant diameter in the range of 20–40 nm. For samples co-doped with Bi 3+ and Eu 3+ , the band at λ = 616–620 nm ( 5 D 0 → 7 F 2 3+ ) is the strongest in comparison with the other bands of the series 5 D 0 → 7 F J ( J = 0, 1, 2, 3, 4), which indicates that the position of Eu 3+ within the YVO 4 matrix is considerably deviated from the centrally symmetric one. The Bi 3+ ions have an effective sensitizing effect on Eu 3+ radiation due to charge transfer from the 6s orbital of Bi 3+ to the 3d orbital of V 5+ and then to the Eu 3+ ion. The efficiency of energy transfer is about 50% for sample YVO 4 : Bi 3+ (5%), Eu 3+ (0.5%) and almost 100% for YVO 4 : Bi 3+ (0.5%), Eu 3+ (5%).