High performance silver nanowire based transparent electrodes reinforced by conductive polymer adhesive

Abstract

Transparent conducting electrodes (TCEs) are an essential component for modern opto-electronic devices such as solar cells, organic light emitting diodes (OLEDs), liquid crystal displays (LCDs), and touch screen panels. However, traditional indium tin oxide (ITO) cannot meet the demand for the next generation highly flexible TCEs, and thus many novel alternative materials and technologies are blooming, such as super-aligned carbon nanotube, graphenes, conducting polymer and metal nanowire and so on. Among them, silver nanowires (Ag NWs) have been considered as one of the most promising technologies for TCEs, featured with superior electrical and optical properties. However, there are still two major challenges for Ag NWs-based TCEs technology to overcome. One is the poor mechanical interconnection between the Ag NWs conducting networks and transparent substrate, the other is the high contact resistance of the junctions among Ag NWs. Here we report a novel two-step electrostatic spraying process to fabricate Ag NWs TCEs composite with selectively coated conductive polymer, i.e. poly 3,4-ethylenedioxythiophene: polystyrenesulfonate (PEDOT:PSS). Additionally, we applied plasma treatment to the materials between two-step electrostatic spraying process, which rendered sintering of junctions between the Ag NWs at room temperature, and thus increasing the conductivity of the TCEs by at least three orders of magnitude. Results showed that by adjusting the electrostatic spraying process parameters, selective deposition can be achieved, i.e. the conductive polymer could tightly bound to the Ag NWs network. As compared to an even distribution of the coating layer in the whole area, selective coating rendered the negligible loss of transmittance (0.2% at most) and excellent adhesion to the substrate. Moreover, the composited TCEs exhibited 85.3% mean optical transmittance and 35.8 Ω/sq sheet resistance. Based on our results, we believe that this technology can be used for roll-to-roll preparation of silver nanowires (Ag NWs)-based TCEs.