Uniform REVO4:Bi3+ micro/nanocrystals via hydrothermal reaction, microstructure, and widely tunable broadband luminescence (RE = Sc, Lu, Y, Gd, Lu0.5Sc0.5, Y0.5Lu0.5, Gd0.5Y0.5)

Bi 3+ ion presents strong UV excitation up to ∼430 nm and is almost not excitable by visible light, which makes it valuable in current lighting technologies. Morphologically uniform Sc 1- x VO 4 : x Bi 3+ ( x  = 0–0.03, 0.005 interval) and RE 0.99 VO 4 :0.01Bi 3+ (RE = Sc, Lu, Y, Gd, Lu 0.5 Sc 0.5 , Y 0.5 Lu 0.5 , Gd 0.5 Y 0.5 ) micro/nanocrystals were successfully prepared in this work by hydrothermal reaction under 180 °C and pH = 8, without using any chelate or surfactant. The solid-solution vanadates were formed as microrods for Sc and nanocrystals for the other RE owing to different reaction pathways. The optimal Bi 3+ content for luminescence is 1 at% ( x  = 0.01) and concentration quenching was analyzed to occur via electric dipole-dipole interaction. The peak wavelength of the excitation/emission band was found to almost linearly increase, accompanied by band broadening, with decreasing cell volume for the series of REVO 4 :0.01Bi 3+ , which was rationalized by considering the energy of metal-to-metal charge transfer (MMCT) and the character of the chemical bond (nephelauxetic effect). Notably, the REVO 4 :0.01Bi 3+ phosphors showed broadband luminescence (FWHM >165 nm) covering almost the entire visible light region in each case, and the center wavelength of emission can be widely and finely tuned from ∼557 to 639 nm by decreasing the size of RE 3+ on demand. Such luminescence performance may allow the micro/nanocrystals to find valuable application in UV-excited white LED lighting and others.