Rafiei Miandashti Ali, Khosravi Khorashad Larousse, Kordesch Martin E, Govorov Alexander O, Richardson Hugh H
Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States.
Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, United States.
ACS Nano. 2020 Apr 28;14(4):4188-4195. doi: 10.1021/acsnano.9b09062. Epub 2020 Mar 26.
Single-particle spectroscopy is central to the characterization of plasmonic nanostructures and understanding of light-matter interactions in chiral nanosystems. Although chiral plasmonic nanostructures are generally characterized by their circular differential extinction and scattering, single-particle absorption studies can extend our understanding of light-matter interactions. Here, we introduce an experimental observation of photothermal chirality which originated from circular differential absorption of chiral plasmonic nanostructures. Using luminescence ratio thermometry, we identify the optical and photothermal handedness and an absolute temperature difference of 6 K under the right and left circularly polarized light. We observe a circular differential extinction parameter () of -0.13 in colloidally prepared gold helicoids and compare our findings with numerical simulations using finite element methods. The simulated data showed that circular differential absorption and the maximum temperature of a small cluster of helical nanoparticles are polarization-dependent. We observed an intensity-dependent photothermal -factor from chiral helicoids that decreases slightly at higher temperatures. We also measure a range of optical -factors from several gold helicoids, which are attributed to the heterogeneity of helicoids in nanoparticles during synthesis. The principles of differential photothermal response of chiral nanomaterials and heat generation described here can be potentially used for thermal photocatalysis, energy conversion, and electronic applications.
单粒子光谱对于等离子体纳米结构的表征以及手性纳米系统中光与物质相互作用的理解至关重要。尽管手性等离子体纳米结构通常通过其圆二色性消光和散射来表征，但单粒子吸收研究可以扩展我们对光与物质相互作用的理解。在此，我们介绍了一种源于手性等离子体纳米结构的圆二色性吸收的光热手性的实验观察结果。使用发光比率测温法，我们确定了光学和光热手性以及在右旋和左旋圆偏振光下6 K的绝对温差。我们在胶体制备的金螺旋体中观察到圆二色性消光参数（）为-0.13，并将我们的发现与使用有限元方法的数值模拟进行了比较。模拟数据表明，螺旋形纳米粒子小簇的圆二色性吸收和最高温度与偏振有关。我们观察到手性螺旋体的强度依赖性光热因子在较高温度下略有下降。我们还测量了几种金螺旋体的一系列光学因子，这归因于合成过程中纳米粒子中螺旋体的异质性。这里描述的手性纳米材料的光热响应差异和热生成原理可能潜在地用于热光催化、能量转换和电子应用。
