In this study, we synthesized organic/inorganic hybrid materials containing cadmium sulfide (CdS) nanoparticles using a novel amphiphilic conducting block copolymer as a synergistic structure-directing template and an efficient exciton quencher of the hybrid. The amphiphilic rod-coil block copolymer of polyphenylene-b-poly(2-vinyl pyridine) (PPH-PVP) was first prepared from its coil-coil precursor block copolymer of poly(1,3-cyclohexadiene)-b-poly(2-vinyl pyridine) (PCHD-PVP) by using sequential anionic polymerization followed by the aromatization reaction of converting the PCHD block to form conducting PPH. The synthesized PCHD-PVP block copolymers self-assembled into different bulk nanostructures of lamellae, cylinders, and spheres at a volume fraction similar to that of many coil-coil block copolymer systems. However, an enhanced chain-stiffness-induced morphological transformation was observed after the aromatization reaction. This is evidenced by the TEM observation in which both spherical and cylindrical structured PCHD-PVPs transform into lamellar structured PPH-PVPs after aromatization. In addition to the bulk-phase transformation, the rigid-rod characteristic of the conducting PPH block also affects the self-assembling property of the block copolymers in their solution state. CdS nanoparticles were synthesized in situ in a selective solvent of THF using PCHD-PVP and PPH-PVP micelles as nanoreactors. The PPH-PVP/Cd ion in THF exhibits a new ringlike structure of uniform size (approximately 50 nm) with PPH in the inner rim and complexed PVP/Cd ions in the outer rim as a result of the effects of strong intermolecular forces between PPH segments and the solvophobic interaction. CdS nanoclusters were subsequently synthesized in situ from the PPH-PVP/Cd(2+) ring structure, forming a nanohybrid with intimate contact between the PPH domain and CdS nanoparticles. In particular, we found that there is an efficient energy/electron transfer between the conducting PPH domain and CdS nanoparticles in the hybrid, resulting in an enhanced PL quenching effect. The novel nanohybrid shows the potential to be used for optoelectronic applications.
We successfully fabricated 5-inch organic thin film transistors array with 320×240 pixels on flexible substrate. All the processes were done by photolithography, spin coating and ink-jet printing.The OTFT-Electrophoretic (EP) pixel structure, based on a top gate OTFT, was fabricated. The mobility, ON/OFF ratio, subthreshold swing and threshold voltage of OTFT on flexible substrate are: 0.01 cm^2/V-s, 1.3 V/dec, 10E5 and -3.5 V. After laminated the EP media on OTFT array, a panel of 5 inch 320×240 OTFT-EPD was fabricated. All of process temperature in 10×10 OTFT-EPD is lower than 150 . The pixel size in our panel is 300 µm × 300 µm, and the aperture ratio is 50 %. The OTFT channel length and width is 20 um and 200um, respectively. We also used OTFT to drive EP media successfully. The operation voltages that are used on the gate bias are -30 V during the row data selection and the gate bias are 0 V during the row data hold time. The data voltages that are used on the source bias are -20 V, 0 V, and 20 V during display media operation.
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