Conductive property of inkjet printed film by reactive silver inks on PET flexible substrate

The particle-free silver conductive ink and the PET film were used as the reactive ink and the substrate respectively. During the printing process, a layer of ink drops would be printed. After that, the printed liquid drops were sintered in an oven to obtain a compact silver layer. Repeat the “printing and sintering” process to form a silver film by a layer-by-layer way. Silver film with several layers was characterized by SEM observation, EDS composition analysis and XRD phase analysis. The result showed that sintered compact of silver film was composed of homogeneously distributed nano-silver particles. The film resistivity was measured by the four-point probe method. The effects of the printed layer number on the film property and the resistivity of the silver sintered compact were studied. The results showed that the film property and the resistivity varied with the number of printed layers. When the number was up to 14, the electric conductivity reached its optimum value 4.8μΩ·cm, and the sintered compact of nano-silver covered 94.5% area of the PET substrate. In the final part of this work, a circuit including LED and printed wires were set up to demonstrate the conductivity of the printed flexible electronics under various conditions.