SAW-Based Aerosol Printing for the Future of Electronics

Surface acoustic wave (SAW) aerosol generation is redefining droplet-based additive manufacturing with its solid-state, microchip approach. Recent advances have significantly enhanced SAW aerosol generators, enabling high-performance atomization at very low power levels. These compact devices have no moving parts and no nozzles, yet can reliably produce micron- and submicron-scale aerosols with tunable droplet sizes. Compared to traditional ultrasonic or mechanical atomizers, SAW-driven systems offer markedly lower power consumption and greater integrability, all while maintaining precise control over droplet formation. This talk will highlight how such recent developments – from power- efficient acoustic drive schemes to refined chip designs – are paving the way for battery-powered, portable aerosol printheads without sacrificing performance. We present the design and fabrication of a SAW-based aerosol printhead chip integrated with microfluidics for versatile ink delivery. The SAW chips are fabricated on piezoelectric substrates using standard photolithography for interdigital transducers, combined with a dry-film photoresist lamination process to create on-chip microfluidic channels that feed liquid into the acoustic interaction zone. This wafer-level integration yields a robust, mass-producible device: the fluid is delivered via an embedded microchannel directly to the SAW active region, where it is immediately atomized. A compact, bi-axially mountable chip holder has been developed to interface these SAW chips with existing aerosol printing systems, allowing the device to be oriented as needed while ensuring stable fluid and electrical connections. We have tested a broad range of inks and fluids – from aqueous and organic solutions to highly viscous nanoparticle inks and even biological suspensions – confirming the device’s wide compatibility and clog-free operation. Experimental results demonstrate finely tunable droplet generation through control of the SAW parameters. By adjusting the SAW wavelength (via transducer geometry), input RF power, and liquid flow rate, we achieve precise control over aerosol droplet size distributions. For example, higher-frequency (shorter wavelength) SAW chips consistently produce smaller droplets at a given flow rate and power, while reducing the liquid flow yields a shift toward smaller droplet diameters. The droplet size can be modulated from the sub-micrometer scale up to tens of micrometers on demand, simply by tuning these operating conditions. Such tunability, combined with the device’s energy-efficient operation and rapid on/off response, underscores the promise of SAW-based aerosol generators in additive manufacturing. In particular, this technology enables a new class of aerosol printing heads that are compact, power-efficient, and capable of depositing fine features with controlled droplet sizes. These advancements illustrate how SAW-driven aerosol generation can contribute to more efficient printed electronics and high-precision, multi-material additive manufacturing, aligning with the future needs of electronics fabrication and sustainable, energy-efficient printing.