Scheme 1 a a Conditions: (a) synthesis scheme of R-vinyl-ω-(phenyl) end-functionalized P3HT; (b) R-vinyl-ω-(phenyl) end-functionalized P3HT is activated by s-BuLi and forms 3, which subsequently serves as an anionic macroinitiator for the synthesis of P3HT-P2VP; dppp ) propane-1,3-diylbis-(diphenylphosphane).

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In this article, we have proposed a nanostructured near-ultraviolet photodetector ͑Ͻ400 nm͒ based on the ZnO nanorod/polyfluorene hybrid by solution processes at low temperature. The current-voltage characteristic of the hybrid device demonstrates the typical pn-heterojunction diode behavior, consisting of p-type polymer and n-type ZnO nanorods, respectively. The relative quantum efficiencies of the hybrid device exhibit a nearly three order difference while illuminated under UV and visible light, respectively. The responsivity for the device can reach to 0.18 A / W at 300 nm by applying a bias of −2 V, which provides a route to fabricate a low-cost near-UV photodetector.

Experimental methods, characterization data and 1 H NMR and 13 C NMR spectra of monomers for all polymers are described below.Materials. Fluorene, 3-bromothiophene, 3-thiophenecarboxaldehyde and malononitrile were obtained from Aldrich Chemical Co. 9,9-Dihexylfluorene. 1 To a solution of 5.0 gm (30.1 mmol) of fluorene in THF (60 ml) at -78 o C was added dropwise, 25 ml (62.5 mmol) of n-butyllithium (2.5 M in hexane).The mixture was stirred at -78 o C for 1 h, and 11.5 gm (70 mmol) of 1-bromohexane in THF (15 ml) was added dropwise to the mixture. The solution was allowed to warm to room temperature and was stirred for overnight. The mixture was poured into water and extracted with ether (3 X 30 ml). The organic layer was washed with brine solution and dried over anhydrous MgSO 4 . The solvent was removed by reduced

An ordered nanostructure can be created from the hybrid materials of self-assembly poly(3-hexyl thiophene-b-2-vinyl pyridine) and nicotinic acid-modified titanium dioxide nanoparticles (P3HT-b-P2VP/TiO(2)). TEM and XRD analyses reveal that the TiO(2) nanoparticles (NPs) are preferentially confined in the P2VP domain of P3HT-b-P2VP whereas TiO(2) NPs interact with either pure P3HT or a blend of P3HT and P2VP to produce microsized phase segregation. The morphologies of lamellar and cylindrical structures are disturbed when the loading of TiO(2) NPs is 40 wt % or higher. Cylindrical P3HT-b-P2VP/TiO(2) exhibits a small blue shift in absorption and photoluminescence spectra with increasing TiO(2) loading as compared to P3HT/TiO(2). The NPs cause a slightly misaligned P3HT domain in the copolymer. Furthermore, the PL quenching of P3HT-b-P2VP/TiO(2) becomes very large as a result of efficient charge separation in the ordered nanodomain at 16 nm. Solar cells fabricated from self-assembly P3HT-b-P2VP/TiO(2) hybrid materials exhibit a >30 fold improvement in power conversion efficiency as compared to the corresponding 0.3P3HT-0.7P2VP/TiO(2) polymer blend hybrid. This study paves the way for the further development of high-efficiency polymer-inorganic nanoparticle hybrid solar cells using a self-assembled block copolymer.

Solution processing of π-conjugated polymers constitutes a major low-cost manufacturing method for the fabrication of many new organic optoelectronic devices. The solution self-assembly kinetics of π-conjugated rod-coil block copolymers of symmetric poly(3-hexyl thiophene)-b-poly(2-vinyl pyridine) (P3HT-P2VP) during drying and the phase transformations of the subsequently dried samples were studied by using a combination of TEM, SAXS, WAXS and DSC measurements. During solution drying in chlorobenzene, a good solvent for the copolymer, P3HT-P2VP first formed nanoseed aggregates followed by the directional growth of nanofibrils driven by the formation of prevailing form II P3HT crystals within its nanofibril core confined by the surrounding domain of P2VP blocks. This result was in sharp contrast when a similar molecular weight P3HT homopolymer was solution self-assembled in chlorobenzene, nearly free from confinement, in which case the resulting nanofibrils consisted of a mixture of majority form I and form II crystals. Solvent-cast films of P3HT-P2VP nanofibrils with form II crystals were heat-/cold-treated and showed solid-state phase transformations from form II crystals to form I crystals, both within nanofibrils with annealing, indicating the metastability of the form II crystals with temperature. A disordered state followed with increasing temperatures which, when cooled, induced the formation of a thermodynamically stable lamellar phase with only form I P3HT crystals. Correspondingly, the study provides new strategies for controlling polymorphs and nanostructures of π-conjugated block copolymers for future applications using solution processing and subsequent heat treatment.

A series of low band gap, highly soluble alternating conjugated copolymers, comprised of 11,11,12,12-tetrahexylindenofluorene and thiophene derivatives (P1-P4), were synthesized via Pd-catalyzed Suzuki coupling reaction with very good yields. Described here are the synthesis, thermal, optical, and electrochemical properties of these new copolymers as potential new active materials for electronic and optoelectronic device applications. P1 and P2 have electron donating non-psubstituents with ethylenedioxy and propylenedioxy bridging the 3,3 positions of the cyclopentadithiophene groups; whereas P3 and P4 have electron withdrawing psubstituents (carbonyl and pyrazine groups on P3 and P4, respectively). For the main absorptions in UV-vis spectrum, P1 and P2 displayed more red absorptions in comparison with P3 and P4. Nevertheless, much suppressed quantum yields are exhibited by P3 and P4. The behaviors of P3 can be attributed to the significant charge transfer interactions between the p-substituents and the conjugated polymer backbone that leads to a less allowed optical transition between the ground and the lowest excited state. For P4, the weak fluoresence might associate with energy transfer from indenofluorene to the low band gap thiophene-pyrazinethiophene-thiophene (T-PT-T) unit. In comparison with the corresponding polymers containing fluorene instead of indenofluorene, the use of indenofluorene exhibited mixed effects on the optical properties and improved solubility. V

A novel series of soluble alternating conjugated copolymers, comprised of 9,9-dihexylfluorene and thiophene or substituted thiophene moieties (P1-P5), were synthesized via the palladium-catalyzed Suzuki coupling reaction. Substitutents on the thiophene include the electron-donating groups of hexyl and hexyloxymethyl group and the electron-withdrawing groups of hexyl carboxylate and cyano. The steric effects of the bulkier substituents outweigh the electronic effects of the substituents on the observed absorption and photoluminescence properties of the copolymers. Therefore, only the cyano substituted copolymer (P4) exhibits a red shift of the electronic spectra with 1.6 times enhancement in the fluorescence quantum yield as compared with the unsubstituted copolymer (P5). The substituents slightly reduce the values of T g and T d of P5, but all of the reported copolymers have a T d larger than 300 °C.