Metal grid conductors for LECs by using high-speed inkjet printing

Light-emitting electrochemical cells (LEC) are thin film electroluminescent devices that have a simple architecture, can be processed from solution and don't rely on air-sensitive charge-injection layers or metals for electron injection. This makes it possible to use high-speed inkjet printing in manufacturing process, specifically for making metal grid conductors. This paper will present the work done at VTT in this area of inkjet printing metal grid conductors based on silver nano-particle ink. The optimisation of the printing process in order to guarantee the best possible electrical performance as well as compatibility development of the ink and ITO-coated substrate have been in focus. Industrial-type inkjet printheads have been used thus making it possible to give estimations on up-scalability of the achieved results. Special attention is paid to printing and curing processes compatible with high-speed roll-to-roll fabrication, such as electrical sintering method. Also benefits of inkjet-based manufacturing process for LECs will be discussed