Modulation of Morphology and Luminescence Property of NaBiF4:Yb3+/Er3+ Upconversion Nanoparticles by Organic Ligands

NaBiF 4 :Yb 3+ /Er 3+ upconversion materials modified by different organic ligands were synthesized by solvent thermal method, and then their morphology and luminescence properties were studied.The results show that the soft template and orientation of the organic ligands can tune the particle size and morphology of the UCNPs, and the defect passivation of the surface organic ligands enhances the luminescence intensity.Especially, the cetyl trimethylammonium bromide (CTAB) and the cetyl trimethylammonium chloride (CTAC) modified materials have the most significant enhancement effect (9 times).Furthermore, the effects of temperature and pH on luminescent properties of the materials were investigated.Results show that, within the range of experimental conditions, the luminescence intensity of the materials decreases with the increase of temperature from 30 to 90 ℃ and significantly reduces under strong acid and alkaline conditions, with maximum at pH 5-6.