Chateau D, Liotta A, Vadcard F, Navarro J R G, Chaput F, Lermé J, Lerouge F, Parola S
Ecole Normale Supérieure de Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie UMR 5182, 46, allée d'Italie, F-69364, Lyon cedex 07, France.
Nanoscale. 2015 Feb 7;7(5):1934-43. doi: 10.1039/c4nr06323f.
Anisotropic gold nanoparticles and in particular with shapes exhibiting tips are known to present an extremely strong localized electromagnetic field. This field is mostly located at the top of the tips and can be used in various optical applications. Moreover, as a consequence of their anisotropy, they present two plasmon resonance bands corresponding to the transverse and longitudinal resonance modes. Tuning the aspect ratio it becomes possible to display SPR bands near the near infrared region. This was particularly investigated in the case of nanorods and also for bipyramids. In this paper we report a high yield synthesis approach that allows one to precisely control the aspect ratio of bipyramids and to elongate the structure until they adopt a javelin-like aspect. We were able to prepare nano-javelins with surface plasmon resonances up to 1850 nm, opening important perspectives in terms of optical applications in the NIR and IR regions. The synthetic methods are fully reported and the optical properties were correlated with the theoretical approach, taking into consideration not only the aspect ratio but also the truncation of the nano-objects.
各向异性金纳米颗粒，特别是具有尖端形状的颗粒，已知会呈现极强的局域电磁场。该场主要位于尖端顶部，可用于各种光学应用。此外，由于其各向异性，它们呈现出对应于横向和纵向共振模式的两个等离子体共振带。通过调整纵横比，可以在近红外区域附近显示表面等离子体共振（SPR）带。这在纳米棒以及双锥体的情况下都进行了特别研究。在本文中，我们报告了一种高产率合成方法，该方法能够精确控制双锥体的纵横比，并延长结构直至其呈现标枪状外观。我们能够制备出表面等离子体共振高达1850纳米的纳米标枪，为近红外和红外区域的光学应用开辟了重要前景。本文全面报道了合成方法，并将光学性质与理论方法相关联，不仅考虑了纵横比，还考虑了纳米物体的截断情况。
