控制面积比率和表面修饰的超薄金纳米棒:形成机制和局部表面等离子共振
Ryo Takahata1, Seiji Yamazoe1,2,3, Kiichirou Koyasu1,2
1Department of Chemistry, School of Science , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku , Tokyo 113-0033 , Japan.
Journal of the American Chemical Society
|April 26, 2018
概括
我们合成了超薄金纳米棒 (AuUNR), 这些纳米金结构具有独特的光学特性,与传统的纳米棒不同.
科学领域:
- 纳米技术
- 材料科学
- 物理化学
背景情况:
- 黄金纳米棒 (AuNR) 在近红外 (NIR) 区域呈现局部表面等离子共振 (LSPR),可根据面积比调节.
- 控制超薄纳米结构的合成对于探索独特的量子束效应至关重要.
- 了解连接物-表面相互作用是定制纳米材料特性的关键.
研究的目的:
- 合成具有控制尺寸的超薄金纳米棒 (AuUNR) (直径2 nm,长度520 nm).
- 通过时间解析光学光谱来研究AuUNR的形成机制.
- 研究连接物交换对AuUNR光学特性的影响.
主要方法:
- 通过使用烯 (OA) 作为表面活性剂缓慢减少金的 AuUNRs 的合成.
- 使用传输电子显微镜 (TEM) 和光学灭绝光谱学进行表征.
- 使用谷酸盐或多基酸盐进行连接物交换.
- 时间解析的光学光谱检测探测器的形成机制.
主要成果:
- 成功合成了可调节长度 (5-20 nm) 和恒定直径 (∼2 nm) 的 AuUNR.
- 据推测,AuUNRs的形成是通过OA内集群发生的.
- 对AR<5的NIR波段产生蓝色转移,暗示非等离子起源 (单电子激发).
- 由于化学界面的阻尼,硫酸盐被动化减弱了LSPR.
- 与相似的面积比率的常规AuNR相比,AuUNR显示出显著的红移LSPR波长,这归因于电子有效质量的增加.
结论:
- 与传统的金纳米棒相比,超薄金纳米棒具有不同的光学特性,因为它们的直径较小.
- 在低面比的酸盐保护AuUNR中观察到的NIR波段可能是由于量子效应而不是等离子现象.
- 纳米线直径的小型化对光学响应产生了深远的影响,为新的纳米级光学应用开辟了道路.
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