88493-55-4Relevant articles and documents
UV polymerization of oligothiophenes and their application in nanostructured heterojunction solar cells
Huisman, Carolien L.,Huijser, Annemarie,Donker, Harry,Schoonman, Joop,Goossens, Albert
, p. 5557 - 5564 (2004)
Thin films of 2,2′-bithiophene (2T) and 2,2′-5′,2″- terthiophene (3T) are polymerized by UV irradiation. The polymerization process can be observed by UV-vis and photoluminescence spectroscopy. If 2T is used as starting material, predominantly 4T (quarterthiophene) is formed, while 6T (sexithiophene) is formed if 3T is used as starting material. The same polymerization reaction occurs if solutions of 2T or 3T in chloroform or toluene are used or if a film of nanocrystalline titanium dioxide (nc-TiO2) is soaked with a 2T or a 3T solution. In the latter case the pores are (partly) filled with 4T or 6T, which acts as hole conductor. A photovoltaic response is observed when nc-TiO2/4T or nc-TiO2/6T interpenetrating structures are irradiated with visible light. The increase of oligomer length from 2T to 3T and the corresponding decrease in orientational freedom of the molecules strongly affects the ease of polymerization and the structural order of the compounds formed.
Solution-phase microwave-assisted synthesis of unsubstituted and modified α-quinque- and sexithiophenes
Melucci,Barbarella,Zambianchi,Di Pietro,Bongini
, p. 4821 - 4828 (2007/10/03)
The facile synthesis of poorly soluble unsubstituted and modified α-quinque- and sexithiophenes under microwave irradiation in the liquid phase is described. The use of microwave irradiation allowed these compounds to be prepared in a few minutes and at high yields by means of the Suzuki cross-coupling reaction. Unsubstituted sexithiophene was obtained in 10 min via the one-pot borylation/Suzuki reaction, purified according to a very simple procedure, and isolated in 84% yield. The efficient synthesis of two new methylated quinque- and sexithiophenes displaying liquid crystalline properties is reported. A new microwave-assisted methodology for the conversion of aldehyde-terminated quinque- and sexithiophenes into the corresponding cyano derivatives is also described. The use of microwaves was extended to the Sonogashira coupling reaction and found to be very effective in the preparation of a quinquethiophene containing acetylenic spacers. The electronic and optical characterization of this compound is reported and discussed in relation to that of unsubstituted quinquethiophene.
STUDY OF PHOTOGENERATED NONLINEAR EXCITATIONS IN A POLYTHIOPHENE MODEL COMPOUND: α-SEXITHIENYL
Zamboni, R.,Ruani, G.,Taliani, C.,Pal, A. J.
, p. 113 - 116 (2007/10/02)
Photogeneration of nonlinear excitations in the six thiophene unit oligomer of polythiophene has been studied.The formation of polarons is inferred from the observation of IRAV modes associated with midgap electronic transitions confirming the theoretical expectations that these electronic excitations are stable in short oligomers.
