Rapid microwave-assisted flux growth of pure 尾-NaYF₄:Yb³⁺, Ln³⁺ (Ln = Er, Tm, Ho) microrods with multicolor upconversion luminescence

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• 作者：Mingye Ding ; Chunhua Lu ; Yaru Ni ; Zhongzi Xu
• 关键词：Microwave-assisted synthesis ; Flux cooling method ; Upconversion ; Crystal growth ; Luminescence ; Crystal structure
• 刊名：Chemical Engineering Journal
• 出版年：1 April, 2014
• 年：2014
• 卷：241
• 期：Complete
• 页码：477-484
• 全文大小：2548 K

文摘

Pure hexagonal 尾-NaYF₄:Yb³⁺, Ln³⁺ (Ln = Er, Tm, Ho) microrods were successfully synthesized for the first time through a rapid microwave-assisted flux cooling method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra were used to characterize the samples. The results indicate that with the prolonged time, the phase of product transforms from orthorhombic YF₃ to hexagonal NaYF₄, while the morphology changes from nanoparticles to hollow microtubes then to solid microrods. The microwave (MW) heating technique allows for a reduction of about 90% in preparation time, making it possible to obtain pure 尾-NaYF₄ microrods within only 12 min. By changing the dopant鈥檚 species, multicolor (yellow, blue, and green) upconversion (UC) emissions can be obtained in 尾-NaYF₄:Yb³⁺, Ln³⁺ under 980 nm laser diode (LD) excitation. The UC mechanisms in Yb³⁺/Ln³⁺ co-doped 尾-NaYF₄ samples were analyzed in detail based on the emission spectra and the plot of luminescence intensity to pump power. Importantly, this synthetic methodology may offer a new alternative in the preparation of high quality rare earth fluorides.