Amplification of Photochemical Chiroptical Activity of Chiral Gold Nanocubes

Abstract 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.