Molten salt synthesis, growth mechanism of β-NaYF4 and tunable luminescence properties of β-NaYF4:Tb3+ microrods

• Pure β-NaYF4 microrods have been prepared by a facile and mass production molten salt method.
• Phase and morphology evolution process as well as the formation mechanism were presented.
• Luminescence properties of β-NaYF4:xTb3+ (x = 0.5, 1, 2.5, 5, 10, 20, 40 mol%) were studied.

Pure β-NaYF4 hexagonal microrods have been prepared via a facile and mass production molten salt method without using any surfactant. The phase and morphology evolution process as well as the formation mechanism were presented systematically on the basis of XRD analysis, SEM and TEM observations of the products at the different reaction time periods. Moreover, the systematical investigation on the luminescence properties of β-NaYF4:xTb3+ (x = 0.5, 1, 2.5, 5, 10, 20, 40 mol%) microrods shows the characteristic emissions of Tb3+ (5DJ → 7FJ′, J = 3, 4; J′ = 3, 4, 5, 6). Under the excitation of single wavelength light of 368 nm, the luminescence colors of the corresponding products can be tuned feasibly from greenish blue to green then to green-yellow by changing the doping concentration of Tb3+.