Benzodithiophene with phenylethynyl substituents and thieno[3,2-b:4,5-bí]dipyrrole have been selected as monomers due to the following considerations:
both monomers contain three fused rings which will confer increased planarity to the polymer backbone; benzodithiophene monomers contain a star-like structure with phenylethynyl electron withdrawing substituents attached to the rigid benzodithiophene core that should render the polymer a lower LUMO energy; by contrast thieno[3,2-b:4,5-bí]dipyrrole monomers have increased donor ability due to the presence of the pyrrole heterocycle, which in turn should generate polymers with a higher energy LUMO; copolymerization of thieno[3,2-b:4,5-bí]dipyrrole with benzodithiophene with phenylethynyl substituents is expected to generate an intermediate LUMO level; both selected monomers should have increased ability to self-assemble through p stacking interactions; the attachment of alkyl substituents to both monomers is necessary for making the polymer soluble.
Bulk heterojunction solar cells will be fabricated. The active layer will be a blend of the synthesized polymer donors (P1, P2, P3) and 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (PCBM) acceptor.
Supramolecular Organization in Electronic Polymers: Block-Copolymers Containing Regioregular Polythiophenes and Liquid Crystalline Polymers
Well-defined rod-rod block copolymers containing regioregular polythiophene and helical liquid crystalline segments will be generated by a combination of living polymerization techniques. Poly(N-hexylisocyanate), poly[(R)-2,6-dimethylheptyl isocyanate], poly(N,N-di-n-hexylguanidine) and poly(g-benzyl-L-glutamate) will be incorporated in block copolymers with regioregular poly(3-hexylthiophene). These novel materials are expected to generate well-ordered supramolecular assemblies with tunable optoelectronic properties. The proposed rod-rod copolymers will be used in organic electronics applications, such as thin film transistors and chemical sensors.
Extensive research is currently directed towards conjugated polymer-quantum dot bulk heterojunction solar cells, an alternative to crystalline silicon inorganic counterparts. To increase the performance of these solar cells, quantum dots must be efficiently blended into the conjugated polymer matrix. Additionally the charge transport through the conjugated polymer quantum dot interface must be improved. Here conjugated polymer-quantum dot networks will be generated using the interaction between quantum dots and polythiophene with alkenyl and thiol side chains. The interaction of thiol and olefin functional groups with the quantum dots is expected to create both an increased interfacial contact and a more effective dispersion of the inorganic phase into the organic matrix.
Novel γ-substituted lactone monomers will be synthesized and employed in ring opening polymerization. Octyloxy and tri(ethylene glycol) monomethyl ether substituted caprolactone will be homopolymerized and copolymerized by thin mediated ring-opening polymerization. The ring-opening polymerization of the functional lactones will generate biocompatible aliphatic polyesters. Hydrophylicity, biodegradation, and bioadeshion of the functional aliphatic polyesters will be correlated with their molecular structure.