Electrolyte‐Gated n‐Type Transistors Produced from Aqueous Inks of WS2 Nanosheets

Solution‐processed, low cost thin films of layered semiconductors such as transition metal dichalcogenides (TMDs) are potential candidates for future printed electronics. Here, n‐type electrolyte‐gated transistors (EGTs) based on porous WS2 nanosheet networks as the semiconductor are demonstrated. The WS2 nanosheets are liquid phase exfoliated to form aqueous/surfactant stabilized inks, and deposited at low temperatures (T < 120 °C) in ambient atmosphere by airbrushing. No solvent exchange, further additives, or complicated processing steps are required. While the EGTs are primarily n‐type (electron accumulation), some hole transport is also observable. The EGTs show current modulations > 104 with low hysteresis, channel width‐normalized on‐conductances of up to 0.27 µS µm−1 and estimated electron mobilities around 0.01 cm2 V−1 s−1. In addition, the WS2 nanosheet networks exhibit relatively high volumetric capacitance values of 30 F cm−3. Charge transport within the network depends significantly on the applied lateral electric field and is thermally activated, which supports the notion that hopping between nanosheets is a major limiting factor for these networks and their future application. Electrolyte‐gated transistors based on air‐brushed WS2 nanosheet networks as an n‐type semiconductor are presented. The transistors exhibit current modulations of >104 with electron mobilities around 0.01 cm2 V−1 s−1 and high volumetric capacitance of 30 F cm−3. Charge transport within the network is found to depend significantly on the lateral electric field and to be thermally activated.