Fine-tune chiroptical activity in discrete chiral Au nanorods

Accurate researches on the surface plasmon resonance (SPR)-based applications of chiral plasmonic metal nanoparticles (NPs) still remain a great challenge. Herein, a series of chiral plasmonic metal NPs, e.g., chiral Au nanorods (c-Au NRs), c-Au@Ag core-shell, and c-Au@TiO2 core-shell NRs, with different chiroptical activities have been produced. Plasmonic circular dichroism (PCD) bands of c-Au NRs can be precisely tailored by tuning the longitudinal SPR (LSPR) and amount of Au NRs as seeds. Besides, a shift of PCD bands within ultraviolet-visible-near infrared ray (UV-vis-NIR) region can also be achieved through the functionalization of a shell of another metal or semiconductor. Interestingly, chirality transfer from c-Au core to Ag shell leads to new PCD bands at the near-UV region. The tuning of PCD bands and chirality transfer are confirmed by our developed theoretical model. Developing chiral Au NRs-based chiral plasmonic nanomaterials with tunable chiroptical activities will be helpful to understand the structure-direct PCD and to extend circularly polarized-based applications.

Automated summary

Accurate research on the applications of chiral plasmonic metal nanoparticles with surface plasmon resonance (SPR) still face challenges. This study demonstrates the production of chiral plasmonic metal nanoparticles with tunable chiroptical activities. The results show that the chiral properties can be precisely tailored by adjusting the longitudinal SPR (LSPR) and the amount of gold nanorods as seeds. The functionalization of a shell of another metal or semiconductor can also achieve a shift of the chiral properties within the UV-vis-NIR region. Chirality transfer from the gold core to the silver shell leads to new chiral properties in the near-UV region.