Tailored Silver Malonate Conductive Ink with Tunable Performance Formulated from Mixed Silver Dicarboxylates

Advancement of printed flexible electronics provides electronic devices with a facile manufacturing process and some innovative characteristics such as bendability and flexibility. The exploitation of functional ink materials is a critical challenge for printed flexible electronics. Silver-based particle-free inks have drawn widespread research interest because of their merits in terms of synthesis, flexibility, and low-temperature processing. Although the fact that various kinds of silver precursors have been employed to formulate silver particle-free inks, they are still not ideal owing to concerns with stability, the synthetic process, and conductivity. On the other hand, as a major component, the type of silver precursors has a significant effect on the performance of the formulated ink and the associated film. Therefore, it is essential to develop silver precursors with desirable properties and study the influence of their types on the ink performance. In this paper, three dibasic silver carboxylates with increasing alkyl carbon chain length were synthesized. Their chemical composition, thermal behavior, and morphologies were investigated in detail. Silver malonate was found to have a relatively low thermal decomposition temperature, excellent stability, and the capacity to be synthesized at room temperature, making it appropriate for ink synthesis. Then, a silver malonate (AgMa) ink was formulated, where the thermal decomposition behavior, the evolution process of the microstructure of the film, and the influence of the length of the alkyl carbon chain on the ink were explored. By utilizing silver oxalate as a co-precursor, the performance of the AgMa ink was effectively enhanced. The research provides a facile and cost-effective way for controlling the decomposition process, film morphology, and electrical performance of silver ink, only by using specially designed mixed silver dicarboxylates as precursors.