Recent advances in aerosol jet printing: process, inks and flexible electronic applications

Aerosol jet printing (AJP) is an emerging mask-less, direct-write additive manufacturing technology with considerable potential for flexible electronics. Its advantages include conformal printing on complex three-dimensional surfaces, broad material compatibility, and high-precision digital patterning. This review systematically summarizes innovative process strategies in AJP, including spanning aerosol jet focusing, deposition, and post-processing for flexible electronics, and highlights recent advances in printable material systems and their applications. First, the working principle of AJP is introduced, with emphasis on pneumatic and ultrasonic atomization, printing characteristics, and the main factors that affect process performance. Key process innovations for high-resolution printing and post-processing are then discussed, and strategies for highly conformal printing on freeform surfaces are analyzed. For material systems, this review summarizes the ink design requirements for AJP and classifies recent progress in representative inks, including conductive, semiconducting, dielectric, and biological inks. In particular, the section on conductive inks focuses on stretchable inks and low-temperature curable inks developed for flexible electronics. Representative applications of AJP are further discussed in flexible electronics, sensors and actuators, energy harvesting and storage devices, bioelectronics, and biomedical devices. Finally, future research directions are outlined, including multi-physics modeling, intelligent conformal printing systems, co-design of high-performance inks, and application-oriented reliability assessment. This review aims to provide a systematic theoretical basis and practical guidance for advancing AJP from laboratory research to engineering applications.