Graphene, a single-atom-thick and two-dimensional carbon material, has attracted great attention recently. Because of its unique electrical, physical, and optical properties, graphene has great potential to be a novel alternative to carbon nanotubes in biosensing. We demonstrate the use of large-sized CVD grown graphene films configured as field-effect transistors for real-time biomolecular sensing. Glucose or glutamate molecules were detected by the conductance change of the graphene transistor as the molecules are oxidized by the specific redox enzyme (glucose oxidase or glutamic dehydrogenase) functionalized onto the graphene film. This study indicates that graphene is a promising candidate for the development of real-time nanoelectronic biosensors.

MXene quantum dots (QDs) are emerging 0D nanomaterials. Here, a new heterostructure is developed based on a 1D photoactive semiconductor and a 0D MXene QD for improved photocatalytic reduction of CO 2 into methanol. Specifically, Ti 3 C 2 QDs are incorporated onto Cu 2 O nanowires (NWs) through a simple self-assembly strategy. It is demonstrated that Ti 3 C 2 QDs not only significantly improve the stability of Cu 2 O NWs but also greatly improve their photocatatlytic performance by enhancing charge transfer, charge transport, carrier density, light adsorption, as well as by decreasing band bending edge and charge recombination. The energy level diagram derived from both experimental measurements and theoretical calculations provide further insights of such hierarchical photocatalysis system.

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A large-area, nest-like ZnO nanowires (NWs) array was prepared through the oxidation reaction between zinc foil and (NH4)2S2O8 at 150 °C for 18 h. CdTe quantum dots (QDs) were linked chemically to the array to form CdTe/ZnO heterostructures based on the good affinity of carboxyl to zinc ions. The molar content of CdTe in the heterostructures can be controlled at the level of 1.2%, 5.1%, and 11.4%, which depends on the soaking time of ZnO array in CdTe solution. The measurements of the optical properties of the as-prepared CdTe/ZnO heterostructures reveal that they can harvest incident lights more efficiently than can unmodified ZnO NWs arrays, whose reflectance was decreased about 20%. The good light-trapping effect and the attachment of CdTe QDs significantly improve the photovoltaic properties of the heterostructure and result in a good rectifying behavior. The photoanode based on the heterostructures has open-circuit voltages of 0.5−0.6 V and a short-circuit current of 0.3 mA/cm2.

Electroluminescence and resistive switching are first realized simultaneously in graphene/SiO2 memristor devices. The electroluminescence peaks can be tuned between 550 nm and 770 nm reliably via setting the device to different resistance states by applying different voltages. The combination of resistive switching and electroluminescence may bring new functionalities for these memristor devices which are fully compatible with silicon-based electronics.