Precise Control over the Spatial Arrangement of Copper Selenide on Au Nanobipyramids by Site-Selective Growth for Dual Plasmonic Nanoarchitectures

Dual plasmonic heterostructures composed of gold nanoparticles (Au NPs) and nonstoichiometric copper chalcogenides (Cu_2‑xE) have garnered attention for their unique electronic interactions between two intrinsically dissimilar constituent domains. However, the site-selective deposition of Cu_2‑xE on Au NPs remains extremely challenging due to the difficulty in controlling nucleation and regioselective overgrowth. Herein, we propose a universal Selenide (Se)-mediated approach for precise spatial control of Cu_2‑xSe on gold nano bipyramids (Au NBPs). By deliberately tuning the surfactant environment, Cu_2‑xSe can be selectively deposited on one waist, both lateral sides, and tips of Au NBPs to form UFO-like, segregated islands, and spindle-like morphologies, respectively. Furthermore, the domain size of the Cu_2‑xSe and the plasmonic properties of Au@Cu_2‑xSe can be controlled by adjusting the amount of selenium (SeO₂) precursor. This work establishes a new strategy for the rational design and fabrication of multicomponent functional nanoarchitectures with precisely controlled compositions and tailored plasmonic properties, thereby expanding their scope of applications.