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Surface acoustic waves (SAWs) that propagate on the surface of a solid at MHz frequencies are widely used in sensing, communication, and acoustic tweezers. However, their properties are difficult to be tuned electrically, and current devices suffer from complicated configurations, complicated tuning mechanisms, or small ranges of tunability. Here a structure featuring a thin-film transistor configuration is proposed to achieve electrically tunable SAW propagation based on conductivity tuning. When a DC gate voltage is applied, the on-site conductivity of the piezoelectric substrate is modulated, which leads to velocity and amplitude tuning of SAWs. The use of carbon nanotubes and crystalline nanocellulose as the channel and gate materials results in high tuning capacity and low gate voltage requirement. The tunability is manifested by a 2.5% phase velocity tuning and near 10 dB on/off switching of the signals. The proposed device holds the potential for the next generation SAW-based devices. [ABSTRACT FROM AUTHOR]

Flexible electronics with highly thermal stability and mechanical strength are highly needed in advanced transportation systems. Semiconducting single-walled carbon nanotubes are one of the leading active materials for such thin film transistors because they are printable, flexible, thermally stable, and mechanically strong. Dielectrics with large capacitance are another major component, and polymer electrolytes are printed for flexible electronics, but they suffer from poor mechanical strength and low operating temperature. Here, a transparent, mechanically flexible, and thermally stable polyfluorinated electrolyte (PFE) is developed with high capacitance by curing printed polyfluorinated resin (PFR) and ionic liquid composite at high temperature. PFE inherits the mechanical flexibility and thermal stability from PFR. The immobilized ionic liquid inside the porous structures of PFE accounts for the high capacitance. With top-gated PFE, fully printed electronically pure single-chirality (6,5) single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) exhibit air stable, consistent, and reliable ambipolar characteristics with high transconductance (1 mS) and small subthreshold swing (<0.15 V dec−1) at low voltage in ambient air for p-type and n-type carriers, and >105 ON/OFF current ratio for both carriers under low operation voltage. [ABSTRACT FROM AUTHOR]

On page 6914, H. P. Li and co‐workers present fully printed air stable carbon nanotube electronics including thin‐film transistors, inverters, and backplanes. Gold nanoparticles are printed as drain/source electrodes, electronically pure single‐chirality (6,5) single‐walled carbon nanotube as active channel materials, polyfluorinated electrolyte as dielectrics layers, PEDOT:PSS as gate electrodes, and poly(methyl methacrylate) as passivation layers on substrates like glass, silicon wafer, kapton, and inorganic light‐emitting diode wafer. [ABSTRACT FROM AUTHOR]