Print And Serve Nanoparticles

To precisely position nanoparticles on the surfaces of arrayed devices such as electronic sensors and solar cells, some researchers use ink-jet printing. The nanoparticle ink typically has to be synthesized and purified in the lab first and then deposited by a printer. A research team led by Ghassan E. Jabbour of King Abdullah University of Science & Technology, in Saudi Arabia, has cut down this multistep process by printing the reactants needed to synthesize gold nanoparticles directly onto a silicon surface in the desired pattern (Angew. Chem. Int. Ed. 2013, DOI: 10.1002/anie.201308429). The researchers begin their reactive ink-jet printing process by filling two print cartridges with chemical ingredients: One contains the reducing agent oleylamine plus a solvent, and the second contains gold(III) chloride trihydrate and a solvent. The team prints picoliter droplets from the first cartridge onto a silicon wafer and then prints droplets from the second cartridge directly on top of the first layer. After three hours in a 120 °C oven, the wafer contains an array of spots filled with gold nanoparticles of uniform diameter. According to Hua Zhang, a materials scientist at Nanyang Technological University, in Singapore, this technique not only uses less material compared with synthesizing nanoparticles via a traditional process, but it also “provides an on-demand facile integration of nanoparticles into various devices.”