▎ 摘　　要

Mixed networks of conducting and nonconducting nanoparticles show promise in a range of applications where fast charge transport is important. While the dependence of network conductivity on the loading level of conductive additive is well understood, little is known about the loading dependence of mobility and carrier density. This is particularly important as the addition of graphene might lead to increases in the mobility of semiconducting nanosheet network transistors. Here, we use electrolytic gating to investigate the transport properties of spray-coated composite networks of graphene and WS2 nanosheets. As the graphene loading is increased, we find that both conductivity and carrier density increase in line with the percolation theory with percolation thresholds (similar to 8 vol %) and exponents (similar to 2.5) consistent with previous reporting. Perhaps surprisingly, we find the mobility increases modestly from similar to 0.1 cm(2)/V s (for a WS2 network) to similar to 0.3 cm(2)/V s (for a graphene network) which we attribute to the similarity between WS2-WS2 and graphenegraphene junction resistances. In addition, we find both the transistor on- and off-currents to scale with loading according to the percolation theory, changing sharply at the percolation threshold. Through fitting, we show that only the current in the WS2 network changes significantly upon gating. As a result, the onoff ratio falls sharply at the percolation threshold from similar to 10(4) to similar to 2 at higher loading. Reflecting on these results, we conclude that the addition of graphene to a semiconducting network is not a viable strategy to improve transistor performance as it reduces the on:off ratio far more than it improves the mobility.