Functional Nanomaterials

  Functional nanomaterials have attracted considerable interest to achieve unconventional electronic, optoelectronic, and fabrication methods, which could enable next generation light emitting diodes, solar cells, phototransistors and field effect transistors. Moreover, the surface tunablity of nanomaterials could provide superior chemical and catalytic properties. 

  The size of QD and its surface chemistry ultimately determine the processability, electronic, and optoelectronic properties. For example, the quantum efficiency of the QD/IGZO phototransistor could be strongly dependent on ligand species. We have achieved fine pattering of QD, high electron mobility, and exceptional photo sensitvity with ligand exchange studies. 

  Moreover, the nanometer scale porosity of functional nanomaterial could provide a unique chance to achieve high-performance catalyst, selective absorbent, and high capacity energy storage materials. Unlike the conventional carbon or oxide based porous materials, the metal chalcogenide based aerogel (chalcogel) could provide broad tunability of band gap, chemical functionality, and surface polarizability. We are conducting investigations of new synthetic strategy and novel application of chaclogels.

  Electrospinning enables the fabrication of homogeneous nanofiber network with a controllable diameter of nanofibers (10 - 1000 nm) and variant structures. Electrospun nanofiber membrane has attracted huge attention in air filtration as a potential alternative for the conventional melt-blown filter. Ferroelectric PVDF/modified PVDF nanofiber is one of the most effective nanofibrous air filter membranes, which exhibits high air filtration efficiency and relatively low pressure drop owing to slip effect (with an ultrathin electrospun nanofiber diameter ~ 70 nm) and remnant polarization of ferroelectricity resulting in electrostatic force enhancement. In addition, electrospun metal/metal oxide nanofibers have been recently exploited as a promising material for electronic devices due to their high surface-to-volume ratio accompanied by high flexibility, high transparency, and high stretchability. We are developing functional nanofibers for air filter, energy application, and electronic devices.