Chen Chih-Yao, Chien Ching-Yun, Wang Chih-Ming, Lin Rong-Sheng, Chen I-Chen
Institute of Materials Science and Engineering, National Central University, Zhongli 320, Taiwan.
Department of Optics and Photonics, National Central University, Zhongli 320, Taiwan.
Materials (Basel). 2022 Mar 15;15(6):2145. doi: 10.3390/ma15062145.
In this work, tunable plasmonic liquid gallium nanoparticles (Ga NPs) were prepared through surface anodizing of the particles. Shape deformation of the Ga NPs accompanied with dimpled surface topographies could be induced during electrochemical anodization, and the formation of the anodic oxide shell helps maintain the resulting change in the particle shape. The nanoscale dimple-like textures led to changes in the localized surface plasmon resonance (LSPR) wavelength. A maximal LSPR red-shift of 77 nm was preliminarily achieved using an anodization voltage of 0.7 V. The experimental results showed that an increase in the oxide shell thickness yielded a negligible difference in the observed LSPR, and finite-difference time-domain (FDTD) simulations also suggested that the LSPR tunability was primarily determined by the shape of the deformed particles. The extent of particle deformation could be adjusted in a very short period of anodization time (7 s), which offers an efficient way to tune the LSPR response of Ga NPs.
在这项工作中，通过对颗粒进行表面阳极氧化制备了可调谐等离子体液态镓纳米颗粒（Ga NPs）。在电化学阳极氧化过程中，Ga NPs会伴随表面出现凹坑形貌而发生形状变形，并且阳极氧化壳层的形成有助于维持颗粒形状的最终变化。纳米级的凹坑状纹理导致了局域表面等离子体共振（LSPR）波长的变化。使用0.7 V的阳极氧化电压初步实现了约77 nm的最大LSPR红移。实验结果表明，氧化壳层厚度的增加在观察到的LSPR中产生的差异可忽略不计，时域有限差分（FDTD）模拟也表明LSPR的可调性主要由变形颗粒的形状决定。颗粒变形程度可在非常短的阳极氧化时间（约7 s）内进行调节，这为调节Ga NPs的LSPR响应提供了一种有效方法。
