Ultimate Charge\nTransport Regimes in Doping-Controlled\nGraphene Laminates: Phonon-Assisted Processes Revealed by the Linear Magnetoresistance

Understanding and controlling the electrical properties\nof solution-processed\n2D materials is key to further printed electronics progress. Here,\nwe demonstrate that the thermolysis of the aromatic intercalants utilized\nin nanosheet exfoliation for graphene laminates allows for high intrinsic\nmobility and the simultaneous control of doping type (<i>n</i>- and <i>p</i>-) and\nconcentration over a wide range. We establish\nthat the intraflake mobility is high by observing a linear magnetoresistance\nof such solution-processed graphene laminates and using it to devolve\nthe interflake tunneling and intralayer magnetotransport. Consequently,\nwe determine the temperature dependencies of the inter- and intralayer\ncharacteristics. The intraflake transport appears to be dominated\nby electron–phonon scattering processes at temperatures <i>T</i> > 20 K, while the interflake transport is governed\nby\nphonon-assisted tunneling. In particular, we identify the efficiency\nof phonon-assisted tunneling as the main limiting factor for electrical\nconductivity in graphene laminates at room temperature. We also demonstrate\na thermoelectric sensitivity of around 50 μV·K<sup>–1</sup> in a solution-processed metal-free graphene-based thermocouple.