Mohammed Shariq, Nik Marić, Gaj Kren Gorše, Rupert Kargl and Rebeka Rudolf* Pages 102 - 109 ( 8 )
Background: The bulk production of Gold Nanoparticles (AuNPs) and their concentrated ink, with desirable properties such as morphology, purity, stability and final Au concentration, remains a challenge.
Objective: (i) Synthesis of AuNPs through Ultrasonic Spray Pyrolysis (USP) from different precursors. (ii) Preparation of their concentrated ink and (iii) Test their feasibility for ink jet printing onto a glossy paper substrate.
Method: Initially, two different start materials were used - precursor: Gold Chloride with its nanoparticles as C-AuNPs, and Gold Acetate with its nanoparticles as A-AuNPs stabilised with PVP40 in deionised water. The concentrated ink was prepared from both AuNPs, and filtered up to the [Au] of 1000 ppm. Ink-jet printing was performed, and the obtained patterns were analysed through SEM.
Results: The [Au] in the obtained solutions, determined through ICP-OES analysis, was, for CAuNPs, about 100 ppm, and 150 ppm for A-AuNPs. In the case of C-AuNPs the solution was rose, and for A-AuNPs violet. TEM investigation revealed that C-AuNPs dominated in a circular shape with size about 18 nm; contrary to this, A-AuNPs were mostly in ellipsoid shape, with size in the longitudinal direction of about 36 nm. EDX analyses detected 99.9 wt. % of Au in both AuNPs, which is evidence that these were of high purity. Due to different AuNPs` sizes and [Au], the colloidal solutions showed maximum absorbance wavelength of 532 nm for C-AuNPs and 528 nm for A-AuNPs. SEM results showed that A-AuNPs were significantly better for printing on the paper substrate than C-AuNPs, due to their ellipsoidal shape, as the flow behaviour had been much smoother through the nozzle as compared to the circular shape. The printed area with A-AuNPs reflected in better incorporation of nanoparticles on the paper surface and high-density connectivity among AuNPs.
Conclusions: C-AuNPs and A-AuNPs were synthesised successfully under optimum parameters of evaporation temperature, reaction temperature and gas flow rates. The spherical shape of C-AuNPs as compared to the ellipsoidal nature of A-AuNPs was due to the rapid sintering of Gold Chloride at a higher temperature of 300ºC as compared to Gold Acetate.
Gold nanoparticles, USP, characterization, ink-jet printing, paper, ellipsoidal shape.
Faculty of Mechanical Engineering, University of Maribor, Maribor (2000), Gymnasium Jurija Vege Idrija, (5280), Gymnasium Jurija Vege Idrija, (5280), Faculty of Mechanical Engineering, Laboratory for Characterization and Processing of Polymer, University of Maribor, Maribor (2000), Faculty of Mechanical Engineering, University of Maribor, Maribor (2000)