Deposition of Ordered Arrays of Gold and Platinum Nanoparticles with an Adjustable Particle Size and Interparticle Spacing Using Supercritical CO₂

Abstract

Gold and platinum nanoparticles were prepared using a reverse micelle technique, creating products with several particle sizes. The stabilized metal nanoparticles can be deposited over long-range distances forming ordered arrays using supercritical carbon dioxide to remove the colloid solvent. The use of supercritical carbon dioxide creates uniformly deposited particle layers and can be removed without disturbing the precipitated particles. We also show that these nanoparticles can be deposited efficiently in nanometer trenches, which is not possible using conventional particle deposition by liquid evaporation.

Nanoparticle film deposition using a simple and fast centrifuge sedimentation method

“…The films show similar tightly packed particle arrangements as those prepared by the supercritical fluid CO 2 (sc-CO 2 ) deposition method (Smetana et al 2008;Wang et al 2010). As described by previous studies (Smetana et al 2008;Wang et al 2010), sc-CO 2 deposition requires a high-pressure chamber, specific skill, and a time-consuming process. It will take more than 3 h to complete the deposition if a volume of a 14 cm 3 high-pressure chamber was used.…”

“…The thickness of the film can be varied by changing the concentrations or the volume of the nanoparticle solution. The surface morphology of these films is comparable to the PbS QD arrays achieved by a sc-CO 2 fluid deposition process (Smetana et al 2008;Wang et al 2010) including those reported on a GaAs substrate (Ullrich et al 2010). In general, the images of the Au and PbS NP films deposited by the CDM procedure reveal fairly homogenous coverage on different substrates.…”

“…Methods to deposit nanoparticles (NPs) on a variety of platforms are a key part of the technology development. Current procedures of depositing nanoparticles on solid surfaces include chemical vapor deposition (CVD) (Okada 2007), physical vapor deposition (PVD) (Kong et al 2001), sputtering (Brodsky et al 1977), lithography (Chou et al 1997), spin coating (Chang et al 2004), pulsed-laser deposition (PLD) (Aziz 2008), and supercritical fluid CO 2 (sc-CO 2 ) deposition (Smetana et al 2008;Wang et al 2010). Most nanoparticle deposition techniques require specific equipment and a high level of technical expertise.…”

“…This process requires an ultra-high vacuum or presence of a background gas (Aziz 2008). The supercritical CO 2 deposition method enables filling nanostructures of substrates with nanoparticles (Smetana et al 2008;Wang et al 2010;Ye et al 2003) but involves operations at high pressure with specialized equipment and knowledge.…”

Photoluminescence under high-electric field of PbS quantum dots

“…15 The electric contacts to the sample were realized either by evaporated metals or silver paste by forming parallel stripes (∼5 mm × 3 mm) with a gap of about 1 mm between them. The electric field across the sample was applied with a steady state kV source.…”