Abstract: This proposed research is aimed at the development of novel nanomaterials for sustainable energies, specifically fuel cells, solar hydrogen production and hybrid solar cells. On the one hand, we will develop novel non-noble metal catalysts and design highly efficient electrodes having nano-architecture to replace or reduce the usage of noble metal catalysts applied in current technology. Various transition metals, such as iron, cobalt and nickel, in the reactive center of the N4-chelat will be evaluated. Also, hybrid nano-architecture electrode will be developed, utilizing carbon nanotubes, carbon nanofibers and graphene nanowalls as the templates, whereon electrocatalysts are introduced. Direct growth approaches for the synthesis are to be applied, which offer the most efficient electron transfer thru out the whole catalyst-support-electrode network to gas diffusion layer. Meanwhile, transparent conducting films (TCF) based on networked carbon nanotubes and graphene are developed to replace indium tin oxide. This carbon based TCF can be fabricated in large scale and shows high potential for flexible electronics applications. The key step lies in the dispersion of carbon nanostructures, in which poly-3-alkyl-thiphene with various head and tail groups will be utilized. By surface modification, one can also adjust the work function of the TCF to be in line with the active layer for improved carrier transfer.
Advanced nanomaterial hybrid solar cells will be the other core focus, which provides advantageous characteristics of both organic and inorganic semiconductors. For the polymer-nanocomposites hybrid solar cells, the conjugated donor/acceptor polymers act as the donor and transport holes, while inorganic materials are then used as the acceptor and electron transporter. The excellent electron transport capability of inorganic semiconductor makes itself per se an excellent electron accepting material. It is also important to fine-tune the energy gap and thus morphology and interface by adjusting the size and shape of the nanocrystals. We will be focusing on various dimensional/shape/size semiconductor nanostructures and their incorporation into the organic polymer, making a hybrid nanocomposite suited for the photovoltaic device. En route to excellence, several obstacles such as phase-separation, poor dispersion of nanocrystal and the hindrance of charge transport caused by the surface modification of the nanocrystal, etc. will be circumvented. We propose to overcome the interfacial incompatibility by surface modification on both nanocrystals and polymers through nanotechnology in combination with synthetic methodology.
Various microscopy, spectroscopy and optoelectronic property measurements will be carried out to unravel the catalytic as well as photovoltaic conversion process, especially the energy/charge transfer within the molecular assemblies and at heterojunctions where efficient exciton transport and dissociation, respectively, take place. In-situ monitoring with surface spectroscopic techniques (Raman spectroscopy and sum-frequency generation) in combination of optical pump will help to resolve their identities. Energy-filtered scanning transmission electron microscopy and x-ray microscopy will help revealing the heterogeneous material morphology with 1-nm resolution. Interfacial species and their dynamics will be interrogated with steady-state fluorescence spectroscopy, whereas ultrafast laser spectroscopy and near-field optical spectromicroscopy will help disclosing the optical field distribution and the Raman composition within the mixed systems with sub 10-nm resolution. Information obtained from these measurements, in combination with theoretical modeling and computational simulation, should confer coherent guidelines to both the material development and the quantum calculation, producing the top-notch research quality.