Synthesis of aromatic poly(pyridinium salt)s and their electrochromic properties

Synthesis of a series of new conjugated electrochromic polymeric pyridinium salts containing main-chain triphenylamine and their electrochromic properties were demonstrated. All polymers exhibit intense UV absorptions at 336-338 nm in DMF and 340-343 nm in thin film form and fluorescence centered at 410-438 nm in DMF and 460-461 nm in thin film form. The electrochromic properties of the films were investigated by electrochemical and spectroelectrochemical methods. Reversible redox signals with stable electrochromic characteristics were obtained via cyclic voltammetry. The electrochromic properties of the polymers remain highly stable after 50 cycles between 0 and 1.2 V

1,1,4,4-Tetracyanobuta-1,3-diene Substituted Diketopyrrolopyrroles: An Acceptor for Solution Processable Organic Bulk Heterojunction Solar Cells

Two small molecules composed of 1,1,4,4-tetracyanobuta-1,3-diene substituted diketopyrrolopyrroles (DPPs) denoted as <b>DPP5</b> and <b>DPP6</b> were synthesized and their photophysical and electrochemical properties were investigated. The frontier molecular orbitals based on empirical relation between cyclic voltammetry redox potentials, experimental IP, and EA energies indicate that these two small molecules can be used as an electron acceptor for the polymer bulk heterojunction solar cells. The BHJ solar cells combined with a low band gap D–A copolymer <b>P</b> as an electron donor exhibits promising power conversion efficiency of 3.90% and 4.95%, with <b>DPP5</b> and <b>DPP6</b>, respectively, after the optimization of active layers, indicating that these small molecules based on DPPs can be the alternative as an electron acceptor to replace fullerene, leading to the low-cost solution-processed polymer solar cells

New monomers and polymers via Diels-Alder cycloaddition

The series of new bis(naphthalic anhydrides) was prepared through Diels-Alder cycloaddition. The Diels-Alder cycloaddition was used as a synthetic route to new phenylated monomers as well as to polymers. All polymers synthesized revealed to be soluble in a wide range of organic solvents such as toluene,THF, chloroform, and displayed high thermostability. Therefore, they can be processed easily and are promising candidates for advanced coating systems as well as for electrooptical applications

Synthesis and photovoltaic properties of new donor-acceptor benzodithiophene-containing copolymers

Four new alternating narrow band-gap copolymers containing benzodithiophene, 4,8-dithiophen-2-yl-benzo[1,2-c;4,5-c'-bis[1,2,5]thiadiazole, 4,9-bis(thiophen-2-yl)-6,7-di(2-ethylhexyl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline, 5,8-dibromo-2,3-bis(5-octylthiophen-2-yl)quinoxaline, and 4,7-bis(5-bromothiophen-2-yl)benzo[1,2,5] thiadiazole units are synthesized under Stille reaction conditions. The structures, molecular masses, and physical properties of the copolymers are studied via H-1 NMR spectroscopy, GPC, cyclic voltammetry, and thermomechanical and thermogravimetric analyses. The polymers show solubility and a broad absorption region (with the band gap in the range from 0.81 to 1.53 eV). All of the polymers are photostable in air, and their levels of the highest occupied molecular orbital vary from -4.98 to -5.30 eV. Polymer solar cells based on these copolymers as donors and fullerene PC60BM as an acceptor show open-circuit voltages in the range 0.16-0.61 V, and the efficiencies of the devices are in the range 0.02-0.49%