Production of Ultrathin and High-Quality Nanosheet Networks via Layer-by-Layer Assembly at Liquid–Liquid Interfaces

High Resolution Image Download MS PowerPoint Slide Solution-processable 2D materials are promising candidates for a range of printed electronics applications. Yet maximizing their potential requires solution-phase processing of nanosheets into high-quality networks with carrier mobility (μ Net ) as close as possible to that of individual nanosheets (μ NS ). In practice, the presence of internanosheet junctions generally limits electronic conduction, such that the ratio of junction resistance ( R J ) to nanosheet resistance ( R NS ), determines the network mobility via μ NS /μ Net ≈ R J / R NS + 1. Hence, achieving R J / R NS < 1 is a crucial step for implementation of 2D materials in printed electronics applications. In this work, we utilize an advanced liquid-interface deposition process to maximize nanosheet alignment and network uniformity, thus reducing R J . We demonstrate the approach using graphene and MoS 2 as model materials, achieving low R J / R NS values of 0.5 and 0.2, respectively. The resultant graphene networks show a high conductivity of σ Net = 5 × 10 4 S/m while our semiconducting MoS 2 networks demonstrate record mobility of μ Net = 30 cm 2 /(V s), both at extremely low network thickness ( t Net < 10 nm). Finally, we show that the deposition process is compatible with nonlayered quasi-2D materials such as silver nanosheets (AgNS), achieving network conductivity close to bulk silver for networks <100 nm-thick.