Kim Jae-Ho, Cha Seungsang, Kim Yoonhee, Son Jiwoong, Park Jeong-Eun, Oh Jeong-Wook, Nam Jwa-Min
Department of Chemistry, Seoul National University, Seoul 08826, South Korea.
Nano Lett. 2021 Sep 22;21(18):7512-7518. doi: 10.1021/acs.nanolett.1c01639. Epub 2021 Sep 7.
Plasmonic electrochromism, a change in the localized surface plasmon resonance (LSPR) with an applied electric potential, has been attracting increasing attention for the development of spectroscopic tools or optoelectronic systems. There is a consensus on the mechanism of plasmonic electrochromism based on the classical capacitor and the Drude model. However, the electrochromic behaviors of metallic nanoparticles in narrow optical windows have been demonstrated only with small monotonic LSPR shifts, which limits the use of the electrochromism. Here, we observed three distinct electrochromic behaviors of gold nanocubes with a wide potential range through in situ dark-field electrospectroscopy. Interestingly, the nanocubes show a faster frequency shift under the highly negative potential, and this opens the possibility of largely tunable electrochromic LSPR shifts. The reversibility of the electrochemical switching with these cubes are also shown. We attribute this unexpected change beyond classical understandings to the material-specific quantum mechanical electronic structures of the plasmonic materials.
等离子体电致变色，即局域表面等离子体共振（LSPR）随外加电势的变化，在光谱工具或光电子系统的发展中受到越来越多的关注。基于经典电容器和德鲁德模型，人们对等离子体电致变色的机理已达成共识。然而，仅通过小的单调LSPR位移证明了金属纳米颗粒在窄光学窗口中的电致变色行为，这限制了电致变色的应用。在此，我们通过原位暗场电光谱观察到了金纳米立方体在宽电势范围内的三种不同的电致变色行为。有趣的是，纳米立方体在高负电势下显示出更快的频率位移，这为电致变色LSPR位移的大幅可调开辟了可能性。还展示了这些立方体电化学开关的可逆性。我们将这种超出经典理解的意外变化归因于等离子体材料特定的量子力学电子结构。
