Photo-thermally controlled Cu nanoparticles density in SWCNT/Cu nanocomposites-based flexible EMI shielding electrodes

Abstract

In this study, single-walled carbon nanotube (SWCNT)/Cu nanocomposites were systematically synthesized from oxidized SWCNTs and Cu formate via photothermal heating. The incorporation of Cu nanoparticles (Cu NPs) on the surface of SWCNTs, especially for a weight ratio of 1 : 20, enhanced the electrical conductivity of the SWCNTs, resulting in a resistivity of 80 μΩ cm. In mechanical bending tests, the nanocomposites showed excellent performance stability for various bending angles, which indicated their suitability for use in flexible electronics. The mechanical flexibility of the SWCNTs significantly delayed crack propagation in Cu NPs, resulting in the structural integrity of the composites being maintained. Furthermore, we measured the electromagnetic interference (EMI) shielding effectiveness of the composites, and its values for the 1 : 5, 1 : 10, and 1 : 20 wt% composites reached 25.5–33.6, 39.9–45.6, and 56.2–60.3 dB, respectively. Thus, the effectiveness increased rapidly with an increase in the Cu content. The feasibility of using the composites as EMI shielding materials was further supported by received signal strength indication (RSSI) measurements for commercial Bluetooth signals. Overall, these findings highlight the high potential of SWCNT/Cu composites for use as conductive materials in advanced flexible electronics.