Directed assembly of bimetallic nanoarchitectures by interfacial photocatalysis with plasmonic hot electrons

Targeted, sequential deposition of metals using localized surface plasmon resonance (LSPR) is a promising fabrication route for solar fuel catalysts and sensors. This work examines liquid-phase, reductive photodeposition of platinum (Pt) nanoparticles onto the longitudinal ends of gold nanorods (AuNR) under surface plasmon excitation. Reductive Pt nucleation is initiated by plasmonic hot electrons at the Au-liquid interface, whose sites are governed by the plasmon polarity. In this work, in situ spectroscopic monitoring of the photodeposition process permitted real-time feedback into AuNR surface functionalization with the Pt precursor, Pt growth kinetics under monochromatic AuNR LSPR excitation, and their evolving light-matter interactions. Energy dispersive spectroscopy (EDS) mappings show Pt deposition was localized toward the AuNR ends. Coordinated X-ray photoelectron spectroscopy (XPS) measurements with density functional theory (DFT) calculations of the Pt-decorated AuNR density of states (DOS) elucidated optoelectronic behavior. Catalytic photodeposition using plasmonic hot electrons provide an economical path towards targeted, hierarchal assembly of multi-metallic nanoarchitectures at ambient conditions with specified optoelectronic activity.