A 3D Plasmonic Antenna-Reactor for Nanoscale Thermal Hotspots and Gradients
A 3D Plasmonic Antenna-Reactor for Nanoscale Thermal Hotspots and Gradients
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DOI：
10.1021/acsnano.1c01046
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发表时间：
2021-04-26
期刊：
影响因子：
17.1
通讯作者：
Halas, Naomi J.
中科院分区：
文献类型：
--
作者：
Dongare, Pratiksha D.;Zhao, Yage;Halas, Naomi J.
等离子体纳米天线将光聚焦在衍射极限以下，产生强烈的场增强，通常在纳米级结内。将纳米结构放置在结内可以极大地增强纳米结构的固有光吸收，导致强烈的光热加热，其最终可能损害纳米结构和纳米天线两者。在这里，我们展示了一个三维的“antennacreactor”的几何形状，导致在大的纳米级的热梯度，诱导大的局部温度增加，同时最大限度地减少周围的天线的温度增加的限制纳米结构反应器。纳米结构支撑在天线间隙内的绝缘衬底上，而天线保持与下面的热导体直接接触。升高的局部温度被量化，并且观察到仅热重塑每个天线-反应器结构内的内部反应器元件的高局部温度梯度。我们还表明，名义上200摄氏度的高局部温度的增加是可以实现的天线反应器图案成大的扩展阵列。这种简单的策略可以促进高温热点的远距离光学产生，这可能在诸如小体积、高通量化学过程的应用中是有用的，其中反应效率指数地取决于局部温度。
Plasmonic nanoantennas focus light below the diffraction limit, creating strong field enhancements, typically within a nanoscale junction. Placing a nanostructure within the junction can greatly enhance the nanostructure's innate optical absorption, resulting in intense photothermal heating that could ultimately compromise both the nanostructure and the nanoantenna. Here, we demonstrate a three-dimensional "antennareactor" geometry that results in large nanoscale thermal gradients, inducing large local temperature increases in the confined nanostructure reactor while minimizing the temperature increase of the surrounding antenna. The nanostructure is supported on an insulating substrate within the antenna gap, while the antenna maintains direct contact with an underlying thermal conductor. Elevated local temperatures are quantified, and high local temperature gradients that thermally reshape only the internal reactor element within each antenna-reactor structure are observed. We also show that high local temperature increases of nominally 200 degrees C are achievable within antenna-reactors patterned into large extended arrays. This simple strategy can facilitate standoff optical generation of high-temperature hotspots, which may be useful in applications such as small-volume, high-throughput chemical processes, where reaction efficiencies depend exponentially on local temperature.