Highly smooth and conductive silver film with metallo-organic decomposition ink for all-solution-processed flexible organic thin-film transistors

A facile silver metallo-organic decomposition (MOD) ink and its two-step sintering process was developed to fabricate highly conductive and smooth silver film for the flexible organic electronics. Using simple and feasible two-step sintering processes and double-layer processes, the conductivity of silver film with the facile MOD ink was greatly improved from 2.85 × 103 S cm−1 to 1.50 × 105 S cm−1, indicating about 53 times increase and about 24% bulk silver conductivity, and the surface RMS roughness was about 6 nm by atomic force microscope, nearly identical to the thermal-evaporated silver film. The XRD showed that synthesized silver thin films were composed of pure silver and well crystallized to the face-centered cubic structure, similar to metallic silver. And the full XPS spectra showed the presence of the same elements and almost identical peaks of solution-processed silver, as compared to the thermal silver surface elemental data. Besides, the silver film also demonstrated great mechanical stability and adhesion on PET substrate. At last, using silver gate/source/drain electrodes generated from the MOD ink, the all-solution-processed organic thin-film transistors (OTFTs) were demonstrated. The optimized OTFTs exhibited a high field mobility of 0.36 cm2 V−1 s−1 with threshold voltage of 0.35 V and on/off current ratio of 1 × 105.