Au/Cu Bimetallic Nanoparticles via Double-Target Sputtering onto a Liquid Polymer

Abstract

Alloy nanoparticles (NPs) of a bimetal system, Au/Cu, that form intermetallic compounds in a bulk state have been successfully produced using a double-target sputtering technique onto a low-cost and biocompatible liquid polymer (polyethylene glycol, PEG). The formation of an Au/Cu solid solution alloy in individual NPs was revealed by scanning transmission electron microscopy-energy-dispersive X-ray elemental mapping analysis. Altering the sputter currents for Au and Cu targets resulted in a tailored NP composition, but the particle sizes did not significantly vary. We found similar structures, sizes, and optical properties of Au/Cu NPs obtained by double-head sputtering on carbon-coated transmission electron microscopy grids or PEG and by Au/Cu alloy target sputtering. Random alloy formation occurred in matrix sputtering using double-target heads. This method is advantageous for manipulating the alloy composition through highly independent control of sputter parameters for each metal target.

Silver nanoparticles by atomic vapour deposition on an alcohol micro-jet

“…[42][43][44] Both ionic liquid (IL) and sufficiently low vapour pressure solvent surfaces are stable in low vacuum and have been investigated as targets for metal deposition and nanoparticle formation. [45][46][47][48][49][50][51][52][53][54] In general, the synthesis in mineral oils is predominantly governed by physical parameters of the plasma, [47][48][49] whilst synthesis in ILs is signicantly governed by the chemistry of the IL. 46,50,53,54 In both systems, particles are commonly stable without added stabilisers or capping agents.…”

“…46,50,53,54 In both systems, particles are commonly stable without added stabilisers or capping agents. [45][46][47][48][49][50][51][52][53][54] In this work we extend on the technique of sputter deposition onto liquid surfaces by introducing liquid into vacuum in the form of a liquid microjet. Liquid micro-jets have been widely used as a tool for studying molecular processes in liquids under vacuum conditions, [55][56][57][58][59] and narrow jets or surfaces of high vapour pressure liquids can be generated which are stable in vacuum over timescales of hours.…”

Sputtering onto a liquid: interesting physical preparation method for multi-metallic nanoparticles

“…They provided elemental mapping of single NPs as direct evidence to further confirm their statement that they had created complete solid solution Au/Ag NPs with tuneable compositions (Figure 9(b)). Further, the authors demonstrated that the method can be used to create Au/Cu alloy NPs of various controllable compositions at room temperature [118]. This is interesting because Au/Cu is commonly known to form intermetallic compounds in the bulk state, but forms random alloys in double-target sputtering (Figure 9(c)).…”

“…Reproduced with permission from (a and b) Ref [117],. copyright 2016 Elsevier, and (c) Ref [118],. copyright 2017 The American Chemical Society.…”

Fabrication and Characterization of Carbon-Based Nanofluids through the Water Vortex Trap Method

“…Ishida et al [12] prepared thiolate-protected fluorescent silver NPs by conducting sputtering deposition onto a liquid matrix. Nguyen et al [13,14] synthesized Ag-Au alloy NPs in a liquid by utilizing a novel approach known as double target sputtering. This method allows the manipulation of NP composition, size, and optical properties by controlling the sputter parameters for each metal target.…”