Photochemically Triggered Assembly of Composite Nanomaterials through the Photodimerization of Adsorbed Anthracene Derivatives

Gold nanoparticles were assembled into three-dimensional aggregates in colloidal dispersions and were attached to ZrO2 surfaces through photoinduced [4 + 4] cycloaddition reactions between adsorbed anthracene derivatives. Composite materials were characterized by ultraviolet/visible/near-IR spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Aggregates of gold nanoparticles with diameters of several micrometers were formed within 45 min of illumination at 355 nm and 130 mW/cm2. Aggregation was attributed primarily to interfacial photodimerization between anthryl groups on different gold nanoparticles, although intramonolayer photodimerization reactions may also have occurred. 9-Anthracenethiolate-capped gold nanoparticles were attached to 2-anthroate-functionalized ZrO2 surfaces upon excitation of anthryl π−π* transitions. ToF-SIMS data and the results of control experiments suggested...