Gahlaut Shashank K, Avalos-Ovando Oscar, Kim Ryeong Myeong, Hussein Ridwan, Juergensen Sabrina, Reich Stephanie, Govorov Alexander O, Nam Ki Tae, Bald Ilko
Institute of Chemistry, University of Potsdam, 14476, Potsdam, Germany.
Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, OH, 45701, USA.
Small. 2025 Jun 22:e2505093. doi: 10.1002/smll.202505093.
Chiral plasmonic nanostructures enable exceptionally high dissymmetry factors (g-factors) compared to chiral molecules and present unparalleled opportunities in light manipulation, polarization-sensitive photochemistry, and chiral sensing. Here polarization-dependent plasmonic chemistry on chiral gold nanocubes (AuNCs) is presented, leveraging the high sensitivity of surface-enhanced Raman scattering (SERS). The AuNCs exhibit strong optical activity and localized surface plasmon resonances acting as highly efficient nanoscale light antennae. Employing the hot electron-induced dehalogenation of 8-Bromoadenine as a model reaction, it is demonstrated that circularly polarized light induces asymmetric reaction rates due to circular dichroism (CD) in hot electron generation efficiency. Astonishingly, the photochemical g-factor, quantified by the differential reaction rate coefficients under left-handed and right-handed circularly polarized light, surpasses its optical counterpart and can be further enhanced by laser intensity. Remarkably, multilayer assemblies of AuNCs exhibit a reversal in photochemical CD, which is tuneable via laser power and enables further g-factor enhancement. Comprehensive electromagnetic simulations of extinction spectra and hot electron generation maps corroborate the profound impact of particle arrangement on the optical g-factor and the g-factor for hot-electron generation. This work demonstrates a systematic approach to enhance the photochemical chiroptical response of chiral AuNCs, paving the way for extraordinary control over chemical reactions with light.
与手性分子相比，手性等离子体纳米结构具有极高的不对称因子（g因子），在光操纵、偏振敏感光化学和手性传感方面展现出无与伦比的机遇。本文介绍了基于手性金纳米立方体（AuNCs）的偏振依赖等离子体化学，利用了表面增强拉曼散射（SERS）的高灵敏度。AuNCs表现出强烈的光学活性和局域表面等离子体共振，可作为高效的纳米级光天线。以热电子诱导8-溴腺嘌呤脱卤作为模型反应进行研究，结果表明，由于热电子产生效率中的圆二色性（CD），圆偏振光会诱导不对称反应速率。令人惊讶的是，通过左旋和右旋圆偏振光下的微分反应速率系数量化的光化学g因子超过了其光学对应物，并且可以通过激光强度进一步增强。值得注意的是，AuNCs的多层组装体表现出光化学CD的反转，这可以通过激光功率进行调节，并能进一步提高g因子。消光光谱和热电子产生图的综合电磁模拟证实了粒子排列对光学g因子和热电子产生g因子具有深远影响。这项工作展示了一种增强手性AuNCs光化学手性光学响应的系统方法，为用光非凡控制化学反应铺平了道路。
