High-throughput piezoelectric droplet dispenser driven by ultra-low voltage

Efficient and facile generation of tiny droplets is critical to many cutting-edge applications, such as flexible electronic skin, customized circuits, and micro-electro-mechanical systems. However, conventional piezoelectric inkjet printing techniques show more prominent problems of high driving voltage and relatively low printing frequency. Here, a novel principle for high-throughput droplet dispensing was proposed based on the resonance of the liquid column within the glass capillary. The mechanisms of this high-throughput piezoelectric droplet dispensing technique were studied both experimentally and theoretically. It is demonstrated experimentally that the resonance frequencies of different orders of the liquid column in the capillary fit perfectly with the theoretical value. It is further demonstrated that when the working frequency is close to the resonant frequency of piezoelectric ceramic, droplets can be ejected out by a driving voltage as low as 1 V. This ultra-low driving voltage and power consumption make this dispenser compatible with various digital transistor–transistor logic or complementary metal–oxide–semiconductor drive circuits without any power amplifier.