Abstract
Chiral plasmonic nanoassemblies demonstrate enhanced chiral optical activity through plasmonic mode coupling, holding transformative potential for applications in sensing, catalysis, and quantum-optical technologies. However, the mechanisms underlying this enhancement-particularly the roles of structural geometry, plasmonic coupling, and chiral field amplification-remain incompletely elucidated. A significant challenge persists in designing coupled nanoassemblies with precisely controlled nanostructures to systematically investigate chirality enhancement. Departing from conventional approaches that incorporate chiral molecules, we present the co-assembly of achiral and chiral plasmonic nanoparticles (NPs) into AB(n)-type nanoclustersand the correlation between inherent plasmonic chirality and the quantity of hotspots. Complementary polymer-grafted achiral nanospheres and chiral nano arrows assemble into stable AB(n) clusters through a combination of electrostatic interactions and hydrogen bonding. The coordination number (n) of AB(n) can be tuned from 2 to 7 by adjusting polymer configurations through modulation of solution pH. The g-factor of AB(n) exhibits a linear increase with the n value of AB(n). Simulation results indicate that the enhanced optical chirality arises from the increase in electric field strength due to the increasing number of hotspots within the NP assemblies.