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NanoSEC Seminar

Hybrid Nanomaterials for Chemical and Biological Sensing  
Guest Speaker
Prof. Junhong Chen  
Guest Affiliation
Department of Mechanical Engineering, University of Wisconsin-Milwaukee  
Wednesday, January 5, 2011 4:00 pm - 5:00 pm  
Riverbend Research South Laboratory Auditorium  

Hybrid nanomaterials comprising nanoparticles (NPs) distributing on the surfaces of carbon nanotubes (CNTs) or graphene/graphene oxide (GO) represent a new class of materials. These materials could potentially display not only the unique properties of NPs and those of CNTs/graphene/GO, but also additional novel properties due to the interaction (e.g., electronic) between the NP and the CNT/graphene/GO. Such hybrid nanostructures are promising for various innovative technological applications, including chemical sensors, biosensors, water treatment, nanoelectronics, photovoltaic cells, fuel cells, and lithium ion batteries. This talk will introduce a material-independent, dry route based on the electrostatic force directed assembly (ESFDA) to assemble both aerosol and colloidal NPs onto CNTs/GO to form NP-CNT/GO hybrid structures. The areal density and the size distribution of NPs onthe CNT/GO can be controlled. Moreover, the non-covalent attachment of NPs preserves the intrinsic properties of CNTs/GO. Due to the inherent material-independence nature of the electrostatic force, various compositions of such NP-CNT/GO hybrids can be produced using this technique. Applications of such hybrid nanomaterials will also be presented for the detection of chemical and biological species. Through the combination of high-performance CNTs/GO and NPs of popular sensing materials, hybrid nanostructures exhibit high sensitivity to low-concentration chemical and biological species at room temperature. For instance, hybrid SnO2 NP-CNT platform allows for the room-temperature sensing of various gases, including those (CO and H2) known to be undetectable by either CNTs or SnO2 NPs alone at room temperature. Such superior sensing performance is attributed to the effective electronic transfer between NPs and the CNT, which facilitates the detection of gases through the change in the electrical conductivity of the hybrid nanostructure. Similarly, a specific biosensing platform based on Au NP and thermally-reduced GO (TRGO) has been demonstrated to successfully detect protein binding events (IgG to anti-IgG). The lower detection limit of the biosensor is on the order of 0.1 ng/ml (~1 pM) and could be further improved by optimizing the device structure. This performance is among the best of all carbon nanomaterial (e.g., CNT, graphene, GO)-based protein sensors.