Numerical and experimental investigation of PZT droplet ejection under pulsed voltage for electrohydrodynamic printing

Abstract Lead zirconate titanate (PZT) has grown increasingly crucial for micro-electro-mechanical systems (MEMS) sensors, including accelerometers, vibration sensors, ultrasonic transducers, and wearable electronic devices. However, most existing fabrication methods face limitations such as incompatibility with traditional MEMS processes and high manufacturing costs. On-demand electrohydrodynamic (EHD) printing enables the low-cost fabrication of micro- and nano-scale PZT structures without the need for a mask. Unlike previous EHD printing techniques that use direct current (DC), this study proposes a PZT EHD printing method employing pulsed voltages, which offers greater flexibility. We developed a simulation model to analyze the formation of droplets under high-voltage pulses, demonstrating the droplet formation mechanisms in both dripping and jetting modes, as well as the accompanying satellite droplet phenomenon. Additionally, we investigated the effects of printing parameters and ink properties on the size of ejected droplets. Results from PZT EHD printing experiments and practical applications confirm that our proposed printing method holds significant potential for the subsequent fabrication of various MEMS PZT sensors.