154717-19-8Relevant articles and documents
'Donor-free' oligo(3-hexylthiophene) dyes for efficient dye-sensitized solar cells
Hu, Yue,Ivaturi, Aruna,Planells, Miquel,Boldrini, Chiara L.,Biroli, Alessio Orbelli,Robertson, Neil
, p. 2509 - 2516 (2016/02/20)
The common trend in designing dyes for use in DSSCs with iodide-based electrolyte is based on a donor-π spacer-acceptor (D-π-A) architecture. Here, we report two 'donor-free' cyanoacrylic end-functionalized oligo(3-hexylthiophene) dyes (5T and 6T). Despite having no donor group, both dyes show reversible first oxidation process. Both 5T and 6T have n-hexyl alkyl chains to retard aggregation at different positions as well as different numbers of thiophene moieties. However, the dyes showed similar absorption properties and redox potentials. The DSSCs based on these dyes give power conversion efficiencies of more than 7%, although a significant difference in the VOC and FF has been observed. Using electrochemical impedance spectroscopy, this is attributed to the presence of more trap states when 6T attaches to TiO2 and modifies the surface, mainly affecting the fill factor. Overall, these dyes introduce a new and effective design concept for liquid-electrolyte DSSC sensitisers.
Concise synthesis of well-defined linear and branched oligothiophenes with nickel-catalyzed regiocontrolled cross-coupling of 3-substituted thiophenes by catalytically generated magnesium amide
Tanaka, Shota,Tanaka, Daiki,Tatsuta, Go,Murakami, Kohei,Tamba, Shunsuke,Sugie, Atsushi,Mori, Atsunori
, p. 1658 - 1665 (2013/02/25)
The synthesis of linear and branched oligothiophenes of well-defined structures is performed with regioselective deprotonation of 3-substituted thiophenes and nickel-catalyzed cross-coupling of the thus formed metalated species with a bromothiophene. The reaction of 3-hexylthiophene with EtMgCl and 2,2,6,6-tetramethylpiperidine (TMP-H, 10 mol %) induces the metalation selectively at the 5-position by use of the catalytically generated hindered magnesium amide (TMPMgCl) and the subsequent reaction of a 2-halo-3- hexylthiophene (bromide or chloride) in the presence of a nickel catalyst affords a head-to-tail (HT)-type dimer. By repeating the same sequence, the linear oligothiophene up to a 4-mer is synthesized in good yield. The reaction of 3-hexylthiophene with 2,3-dibromothiophene also takes place to afford a branched oligothiophene 3-mer in quantitative yield. The obtained 3-mer is also metalated at the sterically less-hindered position in a regioselective manner furnishing a 7-mer in >99 % yield after a further coupling reaction with 2,3-dibromothiophene. These dendrimers react with several multifunctionalized organic electrophiles, leading to a variety of branched oligothiophenes. Copyright
Synthesis of well-defined head-to-tail-type oligothiophenes by regioselective deprotonation of 3-substituted thiophenes and nickel-catalyzed cross-coupling reaction
Tanaka, Shota,Tamba, Shunsuke,Tanaka, Daiki,Sugie, Atsushi,Mori, Atsunori
, p. 16734 - 16737 (2011/12/14)
Iterative growth of thiophene oligomers by single-step extensions has been realized by regioselective metalation of 3-substituted thiophenes with the Knochel-Hauser base (TMPMgCl·LiCl) and coupling with bromothiophene using a nickel catalyst. Treatment of 3-hexylthiophene with TMPMgCl·LiCl induces metalation at the 5-position selectively. Subsequent addition of 2-bromo-3-hexylthiophene and a nickel catalyst leads to the corresponding bithiophene. The obtained bithiophene is converted to the terthiophene and then to the quaterthiophene by repeating the similar protocol. A concise synthesis of MK-1 and MK-2, which are organic dye molecules bearing an oligothiophene moiety that are used in photovoltaic cells, has been achieved.
