Scalable nanoparticle assembly on carbon nanotubes using flash-induced dewetting

Nanoparticle assembly through a novel photothermal dewetting was demonstrated on a macro-scale carbon nanotube (CNT) film. Intense pulsed Xe-light (IPL) was applied to transform a gold (Au) thin-film on CNT into nanoparticles (NPs). Au films measuring 3, 6, and 9 nm were completely dewetted by 10, 20, and 35 J/cm² of IPL intensities, respectively. The means of NP diameters after dewetting were 7.25 nm (standard deviation, σ = 2.23 nm), 13.07 nm (σ = 2.38 nm), and 21.02 nm (σ = 5.86 nm) for the 3, 6, and 9 nm of Au films, respectively. On the other hand, the means of Au NPs formed by furnace annealing were 13.16 nm (σ = 1.78 nm) and 20.98 nm (σ = 15.60 nm) for 6 and 9 nm of Au films, respectively. The 6 and 9 nm of Au films on CNTs were annealed in a furnace at 300 and 400°C, respectively. The distributions of NPs induced by IPL were not significantly different from the result of conventional furnace annealing (p values = 0.45 and 0.96 for 6 and 9 nm Au films, respectively). Finally, thermodynamic stability of IPL dewetted NPs was evaluated by comparing the samples treated with multiple IPL up to five times and with extended thermal annealing up to 10 h.