科研之友
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摘要
Rare-earth-doped up-conversion nanoparticles (UCNPs), which are capable of converting infrared light to shorter-wavelength photons, have attracted worldwide attention due to their unique characteristics. However, the emission brightness of UCNPs is greatly limited by the unsatisfactory absorptivity of lanthanide ions. Herein, we adopted a novel strategy to enhance the up-conversion intensity using NIR dye IR-808 as an antenna to sensitize the core-shell-shell structured NaGdF4: Yb, Er@NaGdF4: Yb@NaNdF4: Yb UCNPs. When excited with 808 nm light, the IR-808 emitted a broadband peak, which perfectly overlapped with the absorption of Nd3+ and Yb3+ ions. Thus, the active shell of NaNdF4: Yb can efficiently capture the emitted NIR photons and transfer them to the transition layer of NaGdF4: Yb. The transition layer acted as an energy bridge to connect the active shell and up-converting zone, avoiding the energy back-transfer from the activators to Nd3+ ions. The optimized dye sensitization combined with the welldesigned core-shell-shell structure tremendously enhances the NIR photon absorptivity of UCNPs and eliminates the deleterious cross-relaxation between the activators and sensitizers, eventually leading to dramatic enhancement of the up-conversion intensity. This study provides a new insight into the dyesensitized up-conversion luminescence of rare earth-based nanoparticles and facilitates their practical applications.
- 出版日期2017-2-7
- 单位哈尔滨工程大学
