Mode-tunable, micro/nanoscale electrohydrodynamic deposition techniques for optoelectronic device fabrication

The rapid development of fascinating new optoelectronic materials and devices calls for the innovative production of micro/nanostructures in a high-resolution, large-scale, low-cost fashion, preferably compatible with flexible/wearable applications. Powerful electrohydrodynamic (EHD) deposition techniques, which generate micro/nanostructures using high electrical forces, exhibit unique advantages in high printing resolution (<1 μm), tunable printing modes (electrospray for films, electrospinning for fibers and EHD jet printing for dots), and wide material applicability (viscosity 1-10 000 cps), making them attractive in the fabrication of high-density and high-tech optoelectronic devices. This review highlights recent advances related to EHD-deposited optoelectronics, ranging from solar cells, photodetectors, and light-emitting diodes, to transparent electrodes, with detailed descriptions of the EHD-based jetting mechanism, ink formulation requirements and corresponding jetting modes to obtain functional micro/nanostructures. Finally, a brief summary and an outlook on the future perspectives are proposed.