Tunable Narrow Band Emissions from Dye-Sensitized Core/Shell/Shell Nanocrystals in the Second Near-Infrared Biological Window

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• 作者：Wei Shao ; Guanying Chen ; Andrey Kuzmin ; Hilliard L. Kutscher ; Artem Pliss ; Tymish Y. Ohulchanskyy ; Paras N. Prasad
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：December 21, 2016
• 年：2016
• 卷：138
• 期：50
• 页码：16192-16195
• 全文大小：309K
• ISSN：1520-5126

文摘

We introduce a hybrid organic–inorganic system consisting of epitaxial NaYF₄:Yb³⁺/X³⁺@NaYbF₄@NaYF₄:Nd³⁺ (X = null, Er, Ho, Tm, or Pr) core/shell/shell (CSS) nanocrystal with organic dye, indocyanine green (ICG) on the nanocrystal surface. This system is able to produce a set of narrow band emissions with a large Stokes-shift (>200 nm) in the second biological window of optical transparency (NIR-II, 1000–1700 nm), by directional energy transfer from light-harvesting surface ICG, via lanthanide ions in the shells, to the emitter X³⁺ in the core. Surface ICG not only increases the NIR-II emission intensity of inorganic CSS nanocrystals by ∼4-fold but also provides a broadly excitable spectral range (700–860 nm) that facilitates their use in bioapplications. We show that the NIR-II emission from ICG-sensitized Er³⁺-doped CSS nanocrystals allows clear observation of a sharp image through 9 mm thick chicken breast tissue, and emission signal detection through 22 mm thick tissue yielding a better imaging profile than from typically used Yb/Tm-codoped upconverting nanocrystals imaged in the NIR-I region (700–950 nm). Our result on in vivo imaging suggests that these ICG-sensitized CSS nanocrystals are suitable for deep optical imaging in the NIR-II region.