Inkjet printing of functional oxide nanostructures from solution-based inks

The inkjet printing of functional oxide nanostructures from solutions provides many advantages when compared to conventionally used top-down patterning methods. It does not require masks and—as the material is deposited only where and when needed—any material-removal steps are not needed. This contributes to reduced waste, cost, and time required to fabricate the device. Despite its apparent simplicity, the inkjet printing process offers many challenges, including the ink chemistry, ink-substrate interaction, and drying; these are discussed in the present review. The ink should have suitable values of viscosity, surface tension, density, and vapor pressure to fulfil the requirements for stable drop formation and pattern formation. The substrate properties are discussed from the points of view of wetting and stability of the printed patterns. Drying of wet deposits without build-up of the material at the edges via the coffee-stain effect is a critical step and strategies to overcome it are discussed. Finally, the potential of inkjet printing technology in many different applications is discussed.