Qiu Hailong, Yang Chunhui, Shao Wei, Damasco Jossana, Wang Xianliang, Ågren Hans, Prasad Paras N, Chen Guanying
School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China.
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA.
Nanomaterials (Basel). 2014 Jan 3;4(1):55-68. doi: 10.3390/nano4010055.
The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF₄:Yb30%/Tm0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF₄:Yb30%/Tm0.5%)/NaYbF₄/NaYF₄ design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF₄:Yb30%/Tm0.5%)/NaYF₄ active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb/Tm-codoped NaYF₄ nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.
镧系掺杂上转换纳米粒子的发光效率对于其在生物光子学和光子学应用中的体现尤为重要。在此，我们表明，通过分级活性核/活性壳/惰性壳（NaYF₄:Yb30%/Tm0.5%）/NaYbF₄/NaYF₄设计，典型使用的NaYF₄:Yb30%/Tm0.5%纳米粒子的上转换发光可增强约240倍，该设计涉及在第二活性壳层中使用定向能量迁移。当在约980nm激发时，所得的活性核/活性壳/惰性壳纳米粒子被确定比经过充分研究的（NaYF₄:Yb30%/Tm0.5%）/NaYF₄活性核/惰性壳纳米粒子亮约11倍。通过定向能量迁移增强Yb/Tm共掺杂NaYF₄纳米粒子上转换的策略可能对其他类型的镧系掺杂上转换纳米粒子有影响。
