Chemical solution deposition via ink jet printing of aqueous Al-doped ZnO precursors

Al-doped ZnO (AZO) is a promising transparent conductive oxide (TCO). Due to its excellent optical an electrical properties, it is a future candidate to replace the nowadays used ITO thin films in devices such as LCDs, LEDs, touch screens, etc. Chemical solution deposition (CSD) is an attractive method to prepare thin films due to its simplicity and low costs. Ink jet printing is selected as deposition technique due to its good scalable process and flexibility towards the deposition of patterns or films. The commonly used solvents in literature are toxic organic solvents such as 2-methoxyehtanol are replaced by the more environmental friendly water. The formulation of these aqueous precursors is selected with care towards stability, wettability with a glass substrate, jettability and the final morphology. Avoiding precipitation in solution of during the gellation process can be controlled by the addition of complexing agents, while additives of tensioactive components control the wettability and jettability. Finally, it’s observed that the formed complexes and the chosen thermal process have a big influence on the crystallinity.