Preparation and characterization of solution-processed MWCNT/Ag matrix composite films

A method for the synthesis of solution process-based MWCNT/Ag NPs composite ink is presented in this paper. Thin films as electrode or interconnect materials for flexible electronic device were produced after sintering the CNT/ Ag tracks. Given that CNTs has large specific surface area and high specific surface energy, it´s challenging to evenly disperse composite ink with CNTs in the metal matrix due to the aggregation of CNTs. In this paper, ultrasonic method has been introduced to disperse CNTs in our composite ink. It was found that proper ultrasonic time produces homogeneously-dispersed CNT networks and increases the density of the Ag matrix, which are major factors in determining the electrical performance of CNT/Ag films. The effect of sintering pressure was studied and the optimal pressure was found based on the measured resistivity. The resistance of MWCNTs/Ag NPs tracks reduced until the pressure increased to 25 MPa. Using the presented ink preparation method and sintering process, electrical properties of fabricated thin films are greatly improved.