Inkjet printing provides an interesting technology for electronic devices, as it is a versatile minimum-waste cost-effective technique for direct writing on almost every surface without need of masks or sacrificial layers. Among the fields in which it has been tested, transparent and flexible electronics offer a variety of applications ranging from large-area roll-toroll (such as OLEDs for lighting or solar cells) to small low-consumption biocompatible devices such as biosensors.
This work aims to present some advances in the field of semiconductors synthesized by sol-gel and patterned by inkjet printing. Chemical routes are used to obtain suitable inks, based on salts of Ga, In, Zn, Cu and Sn and solvents as methoxyethanol. Inkjet printing provides thin layers 20-300nm thick, with morphology strongly depending on the materials. Different thermal treatments are tested, and some chemical and optical characterization of the obtained layers allows optimizing the technology for each material.
The effectiveness of the inks and the technique is demonstrated by the electronic behavior of thin-film transistors fabricated by the proposed technology. The different devices are compared, suggesting the properties of the different materials analyzed, as a step ahead in the development of a complete logic for such promising applications of the flexible electronics.