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Abstract: In this study we used Suzuki cross-coupling to synthesize three new donor/acceptor copolymers—PFTBO, PAFTBO, and PCTBO—featuring soluble alkoxy-modified 2,1,3-benzooxadiazole (BO) moieties as acceptor units and electron-rich building blocks—dialkyl fluorene (F), alkylidene fluorene (AF), and carbazole (C), respectively—as donor units. These polymers, which we characterized using gel permeation chromatography, thermogravimetric analysis, NMR spectroscopy, UV–Vis absorption spectroscopy, and electrochemical cyclic voltammetry, exhibited good solubility, low-lying energy levels for their highest occupied molecular orbitals, excellent thermal stability, and air stability. Using these polymers, we fabricated bulk-heterojunction solar cell devices having the structure indium tin oxide/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate/polymer:[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) (1:1, w/w)/Ca/Al. Under AM 1.5G illumination (100 mW cm−2), the solar cell incorporating PFTBO exhibited a high value of V oc of 1.04 V and that based on PCTBO provided a power conversion efficiency of 4.1% without the need for any post treatment. [Copyright &y& Elsevier]

A series of novel polyimides (PIs) were polymerized from 4,4′-(cyclohexane-1,4-diylbis (oxy))bis(3-(trifluoromethyl)aniline) (1) and 1,4-bis((4-amino-2-(trifluoromethyl) phenoxy)methyl)cyclohexane (2), with two aromatic tetracarboxylic dianhydrides using the typical one-step method. The inherent viscosity of these resulting PIs were in the range of 0.53–0.91 dl/g in N,N-dimethylacetamide (DMAc) at 30°C. They were readily soluble in numerous solvents, such as N-methyl-2-pyrrolidone (NMP), DMAc, N,N-dimethylformamide (DMF), meta-cresol (m-Cresol), and dimethylsulfoxide (DMSO). The PI films showed high optical transparency and were colorless with an ultraviolet-visible absorption cut-off wavelength around 330 nm, and a low dielectric constants of 2.49–2.93 at 1 MHz. The PIs also showed good thermal properties. Their glass-transition temperatures (T g) were higher than 337°C, and the temperatures of 10% weight loss in air and nitrogen were higher than 412°C and 417°C. Furthermore, the PI films possessed good mechanical properties with tensile strengths of 54–71 MPa, elongations at break of 11.6%–17.3% and low moisture absorption (<1.34%). Due to their properties, these PIs could be considered as materials for photoelectric and micro-electronic applications. [ABSTRACT FROM PUBLISHER]

Novel fluorinated polyimides were prepared from an unsymmetrical diamine, 3-methyl-4-(4-amino-2-trifluoromethylphenoxy)-4'-aminobenzophenone ( 3), with four aromatic dianhydrides via a one-step high-temperature polycondensation procedure. All the obtained polyimides were soluble in some polar solvents such as NMP, DMAc, and DMF. Flexible and tough films were prepared by casting from polymer solution. These polyimide films exhibited high optical transparency, good mechanical and thermal properties. Moreover, they possessed low dielectric constants and low-moisture absorption. Due to their properties, these fluorinated polyimides could be considered as photoelectric and microelectronic materials. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

PBDTBO, a conjugated polymer comprising benzo[1,2-b:4,5-b′]dithiophene (BDT) and 5,6-bis(octyloxy)benzo[c][1,2,5]oxadiazole (BO) units, exhibits a deep HOMO energy level of −5.27 eV and excellent solubility. A device incorporating PBDTBO and [6,6]-phenyl-C61-butyric acid methyl ester (1 : 1, w/w) exhibited a power conversion efficiency of 5.7%. [ABSTRACT FROM AUTHOR]