Enhanced Upconversion Luminescence in Yb3+/Tm3+-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles through Directed Energy Migration

• Main Authors: Hailong Qiu, Chunhui Yang, Wei Shao, Jossana Damasco, Xianliang Wang, Hans Ågren, Paras N. Prasad, Guanying Chen
• Format: Article
• Language: English
• Published: MDPI AG 2014-01-01
• Series: Nanomaterials
• Subjects: upconversion; efficiency; core/shell; energy migration
• Online Access: http://www.mdpi.com/2079-4991/4/1/55
• ISSN: 2079-4991

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:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF4:Yb3+30%/Tm3+0.5%)/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:Yb3+30%/Tm3+0.5%)/NaYF4 active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb3+/Tm3+-codoped NaYF4 nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.