Self-assembly based plasmonic nanoparticle array coupling with hexagonal boron nitride nanosheets

Investigation of hexagonal boron nitride nanosheet (BNNS)/plasmonic nanoparticle (NP) composites is of crucial importance for developing plasmaron-based nanodevices. In this study, a simple and effective way for depicting the fabrication of BNNS/Au NP nanocomposites is reported. Diblock copolymer-based NP arrays exhibiting high hexagonal ordering and offering easy control of particle size are utilized to produce Au NP arrays by directly bonding them to BNNSs on a large scale, allowing to investigate the underlying physics of the metal/BNNS interface. The coupling between BNNSs and plasmonic Au NP arrays, work function, charge transfer and surface-enhanced Raman scattering (SERS) of BNNS phonon modes are explored. It is revealed that local surface plasmon resonance (LSPR) of Au NPs induces an electromagnetic mechanism responsible for enhanced Raman results of BNNSs when placing them below Au NPs. In contrast, essential contribution of chemical enhancement from charge transfer induced by energy realignment at the metal/BNNS interface is manifested in hybrid systems of Au NPs and encapsulated BNNS. This work is the first demonstration on evolution of plasmon resonance and charge-based interactions dependent on metal/BNNS interface, thus providing straightforward implications to further develop BNNS-based plasmonics, optoelectronics, and electronics.