Plasmonic nanoscale temperature shaping on a single titanium nitride nanostructure
Plasmonic nanoscale temperature shaping on a single titanium nitride nanostructure
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DOI：
10.1039/d2nr02442j
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发表时间：
2022-08-09
期刊：
影响因子：
6.7
通讯作者：
Setoura, Kenji
中科院分区：
文献类型：
--
作者：
Tamura, Mamoru;Iida, Takuya;Setoura, Kenji
在纳米尺度上任意成形温度场是纳米技术的一个重要目标；然而，由于热传递的扩散性质，这是具有挑战性的。在本工作中，我们用数值方法证明了单个氮化钛(TiN)纳米结构的等离子体加热可以实现纳米尺度温度场的空间整形。与Au(k(Au)=314[Wm(-1)K-1])等普通等离子体金属相比，TiN的一个重要特征是导热系数低(k(TiN)=29[Wm(-1)K-1])。当金属纳米结构的局域表面等离子体共振被激发时，光强度通过焦耳加热效应转化为纳米结构中的热功率密度。对于金纳米粒子，由于金的高导热系数，热功率密度的不均匀空间分布将消失，纳米粒子表面将完全等温。相反，由于热耗散被抑制，热功率密度的空间分布可以清楚地转录成TiN纳米结构上的温度场。事实上，我们发现高度局域的温度分布可以选择性地控制在TiN纳米结构周围，根据激发波长的不同，空间分辨率可以达到几十纳米。结果表明，通过设计TiN纳米结构中等离子体加热的热功率密度，可以实现纳米尺度的任意温度整形，从而产生非传统的热流体和热化学生物学。
Arbitrary shaping of temperature fields at the nanometre scale is an important goal in nanotechnology; however, this is challenging because of the diffusive nature of heat transfer. In the present work, we numerically demonstrated that spatial shaping of nanoscale temperature fields can be achieved by plasmonic heating of a single titanium nitride (TiN) nanostructure. A key feature of TiN is its low thermal conductivity (k(TiN) = 29 [W m(-1) K-1]) compared with ordinary plasmonic metals such as Au (k(Au) = 314 [W m(-1) K-1]). When the localised surface plasmon resonance of a metal nanostructure is excited, the light intensity is converted to heat power density in the nanostructure via the Joule heating effect. For a gold nanoparticle, non-uniform spatial distributions of the heat power density will disappear because of the high thermal conductivity of Au; the nanoparticle surface will be entirely isothermal. In contrast, the spatial distributions of the heat power density can be clearly transcribed into temperature fields on a TiN nanostructure because the heat dissipation is suppressed. In fact, we revealed that highly localised temperature distributions can be selectively controlled around the TiN nanostructure at a spatial resolution of several tens of nanometres depending on the excitation wavelength. The present results indicate that arbitrary temperature shaping at the nanometre scale can be achieved by designing the heat power density in TiN nanostructures for plasmonic heating, leading to unconventional thermofluidics and thermal chemical biology.