Electronic properties and circuit applications of networks of electrochemically exfoliated 2D nanosheets.

Abstract

High aspect-ratio 2D materials are promising for solution-processed electronics, yet the factors controlling exfoliation remain unclear and relatively few solution-processed networks have been electrically characterized. Here we combine theory and experiment to show that electrochemical exfoliation of layered crystals with sufficient stiffness-anisotropy (in-plane/out-of-plane Young's modulus ratio >1.7) yields high aspect-ratio nanosheets with intrinsic mobilities μ_NS = 20-75 cm²V⁻¹s⁻¹ across transition metal dichalcogenides and related alloys. Impedance spectroscopy indicates that solution-deposited networks can achieve junction-to-nanosheet resistance ratios (R_J/R_NS) as low as ~3, supporting theoretical predictions that μ_NS/μ_Net = R_J/R_NS + 1 and suggesting that further reductions in R_J will increase μ_Net toward the nanosheet limit (μ_NS). These networks display n-type, p-type, and ambipolar behaviour, with on/off ratios up to 10⁵ and mobilities μ_Net = 13 cm²V⁻¹s⁻¹. Here, we show that such high-performing 2D materials enable functional solution-processed circuits, including inverters, buffers, a 4-bit digital-to-analog converter, and a circuit capable of encoding and decoding 7-bit ASCII messages.