An air-stable DPP-thieno-TTF copolymer for single-material solar cell devices and field effect transistors

Following an approach developed in our group to incorporate tetrathiafulvalene (TTF) units into conjugated polymeric systems, we have studied a low band gap polymer incorporating TTF as a donor component. This polymer is based on a fused thieno-TTF unit that enables the direct incorporation of the TTF unit into the polymer, and a second comonomer based on the diketopyrrolopyrrole (DPP) molecule. These units represent a donor–acceptor copolymer system, p(DPP-TTF), showing strong absorption in the UV–visible region of the spectrum. An optimized p(DPP-TTF) polymer organic field effect transistor and a single material organic solar cell device showed excellent performance with a hole mobility of up to 5.3 × 10–2 cm2/(V s) and a power conversion efficiency (PCE) of 0.3%, respectively. Bulk heterojunction organic photovoltaic devices of p(DPP-TTF) blended with phenyl-C71-butyric acid methyl ester (PC71BM) exhibited a PCE of 1.8%

Electronic Properties of Sulfur Containing Conjugated Polymers

Valence effective Hamiltonian (VEH) calculations are performed on a number of sulfur containing organic conjugated polymers of interest to the conducting polymers area. Theoretical results for parameters related to conductivity such as ionization potentials, bandwidths, and bandgaps are presented. Systems considered include various derivatives of poly (p-phenylene sulfide), polybenzothiophene, and poly thiophene, as well as potentially interesting compounds such as polythieno [3,2-b] thiophene and polyvinylene sulfide. The electronic structure description afforded by the VEH method for sulfur containing polymers is demonstrated to be of the same quality as that presented previously for hydrocarbon polymers. In particular, for ionization potentials, good agreement with available experimental data on poly (p-phenylene sulfide) and polybenzothiophene is obtained, after scaling downward the VEH values by a 1.9 eV polarization correction. The comparison between the theoretical and experimental XPS spectra for polybenzothiophene is excellent with use of the same energy scaling factor previously employed for polyacetylene, poly(p-phenylene), and poly(p-phenylene sulfide). These results, in conjuction with previous results obtained on hydrocarbon polymers, lend confidence in the predictive capabilities of this purely theoretical technique. Calculations show that polyvinylene sulfide, as yet unsynthesized, should display very promising characteristics as a conducting polymer

New class of soliton-supporting polymers: TheoreNcal predictions

Theoretical predictions for a new class of organic polymers, polyarenemethides, are presented and discussed. These polymers are designed to possess degenerate ground-state bonding patterns as in transpolyacetylene, thus allowing for the existence of isolated soliton defects. The generic backbone is given by the repeat unit [-phenyl-CH=quinoid=CH-]

Poly(thiophene)s prepared via electrochemical solid-state oxidative cross-linking. A comparative study

A comparative study of solid-state oxidative cross-linking (SOC) of polynorbornylenes containing thiophene (N1T), bithiophene (N2T), and terthiophene pendants (N3T) probing polymerization ability, kinetics, and the electrochemical and optical properties of the resulting conductive polythiophene interpenetrating networks (IPN)s is reported. Generally, conductive IPNs prepared from these systems were found to exhibit the capability to shuttle ions with predominant anion transport during the doping/ dedoping process and were found to have doping levels ranging from 17 to 36%. N2T was found to produce conductive IPNs via SOC with a lower energy ?? to ??* transition compared to those prepared from N3T