| 초록 |
The small molecule-polymer blend semiconductors for thin film transistors exhibit superior charge mobility, processability, and stability as compared with neat small molecule and polymer semiconductors. The underlying mechanism is shown to be the nanostructured vertical phase separation of small molecule semiconductors at the gate interfaces most critical to the charge transport. Moreover, the process of forming pure crystalline small molecule semiconductors from the blends removes the impurity components at the critical gate interface. Such zone-refinement effect is considered to be most critical to achieving a much greater charge transport in organic thin film transistors and possibly in bulk-heterojunction organic photovoltaics as well. Nanostructure and charge transport were also investigated for novel polymer electrolyte membranes for fuel cells under anhydrous condition at intermediate temperatures (100-150 C). The synthesized polymer contains the phosphonic acids as the protogenic moiety attached to polystyrene backbone via flexible spacers. The nanostructure and chain dynamics in proton conducting channels of the polymer films is shown to be correlated with measured proton conductivity results versus temperature. Finally, hyperbranched poly(ethylene oxide) based polymers were investigated as solid polymer electrolytes for Li-ion batteries. The Li-ion conductivities, measured for polymers with various nanostructures, show very close correlations with fast segmental dynamics measured by inelastic neutron scattering experiments. |
