Improved mechanical performance of solution-processed MWCNT/Ag nanoparticle composite films with oxygen-pressure-controlled annealing

A method for the synthesis of solution process-based MWCNT/Ag nanoparticle composite thin films as electrode or interconnect materials for flexible electronic devices is presented. The method produces homogeneously-dispersed CNT networks and increases the density of the Ag matrix, which are major factors in determining the mechanical performance of CNT/Ag films. By introducing nanometer-sized Ag particles as a matrix material, the agglomeration of CNTs is suppressed. In addition, the generation of pores during the synthesis procedure is effectively restrained by oxygen-pressure-controlled annealing. The elastic modulus of the pristine Ag films was observed to increase by 34% by adding 5 wt% CNTs. An improvement in the fatigue resistance of the CNTs under cyclic tensile deformation was confirmed. The normalized resistance change ((R - R _o)/R_o) of the Ag films containing 5 wt% CNTs after fatigue testing was reduced by about 27% compared to that of the pristine Ag films. For industrial application the process has the advantage of relatively low-temperature processing without any high pressure compaction compared to the conventional powder metallurgy techniques normally used.