講演情報
[15p-K506-13]Plasmonic and Photothermal Response in Au/Pt Nanogap: Effect of Pt Length
〇(D)Tong Zhou1, Maria Vanessa Balois-Oguchi1, Yutaka Majima2, Kotaro Kajikawa1 (1.School of Engineering, Science Tokyo, 2.Materials and Structures Lab., Inst. of Integrated Research, Science Tokyo)
キーワード：
metal nanostructure、Au/Pt nanogap、SPR、electromagenetic heating
Au/Pt nanogaps in aqueous environments have been used for creating single-molecule junctions and single-electron transistors. These works have primarily focused on the devices’ electronic transport properties and molecular stability; however, the plasmonic and photothermal effects under laser illumination remain unclear and are critical for optimizing the performance of Au/Pt nanogap-based systems, particularly to prevent desorption of adsorbates at the nanogap junction. [v1] In this study, we investigate the effects of the Pt electrode length L on field enhancement and temperature rise by employing COMSOL Multiphysics® to simulate the plasmonic response and electromagnetic heating of Au/Pt nanogaps (gap distance = 1 nm; Au/Pt diameter = 20 nm) in water under 632.8 nm laser illumination, as shown in Figure 1a. Figure 1b illustrates that at L = 35 nm, plasmonic resonance leads to a peak field enhancement of 500 and a temperature rise of 50 K at the gap. For L > 50 nm, the temperature rise significantly decreases (< 15K) and varies slightly with L, while the electric field remains highly sensitive to L and achieves enhancement exceeding 300 at L = 150 nm and 300 nm. At such a low temperature rise with respect to room temperature (T0 = 293.15 K[v2] ), overheating and molecular desorption can be avoided at the nanogap. These findings provide valuable insights into the plasmonic enhancement and photothermal effects in Au/Pt nanogaps, offering theoretical guidance for improving nanogap-based system design.