Current approaches to print micro and nanoparticles are promising, but have serious limitations to commercial applications. These methods require high power consumption and have complicated and costly set-up. These systems are low-throughput, have limited pattern size and resolution-tunability, and difficult alignment.
In response to these challenges, investigators at University of California at Berkeley have developed zero-power nanoparticle printing system. This system uses gravity and surface tension to generate and print picoliter-scale droplets for high-throughput, size-tunable printing of micro, nanoparticle assemblies. High-throughput, picoliter-scale droplets are printed by a single step, contact-transferring of the droplets through microporous nanomembrane of a printing head. Rapid evaporative self-assembly of the particles on a hydrophobic surface leads to printing a large array of various microparticles and nanoparticles assemblies of tunable sizes and resolutions. With this technology, continuous printing of single type particles and multiplex printing of various types of particles with accurate alignment are successfully performed.
As a demonstration of this innovation, the investigators have produced size-tunable, uniform large arrays of gold nanoparticle assemblies for Surface Enhanced Raman Spectroscopy (SERS) are created. Strong and uniform (<10% variation) SERS signals were obtained and the signal is tunable by controlling the pattern sizes. Also, the superb uniformity of the printed patterns is demonstrated in a quantitative manner. This technology offers a straightforward, efficient methodology to manufacture nanophotonic and nanoelectrical devices in a controllable way with low power and material consumption.