Ipek Osken

Reversible Doping of a Dithienothiophene‐Based Conjugated Microporous Polymer

Dithienothiophene (DTT) based conjugated microporous polymers (CMPs) were synthesized by bulk and electrochemical oxidative polymerizations. Spectroelectrochemical measurements showed that DTT-CMP can be reversibly oxidized and reduced, accompanied by a significant change of the absorption properties making the material interesting for electrochromic devices. Reversible doping and dedoping of the bulk polymer network was also observed using iodine and ammonia, respectively. Nitrogen gas sorption measurements of the neutral, doped, and dedoped polymer networks indicated the presence of iodide species within the pores, and the conductivity of the networks is highly increased upon doping with iodine. The introduction of the strong electron donor DTT into a conjugated porous network, and the ability for redox switching, make DTT-CMPs interesting materials for organo(opto)electronic devices and sensors.

Long wavelength photoinitiated free radical polymerization using conjugated thiophene derivatives in the presence of onium salts

Long wavelength free radical photopolymerization of (meth)acrylic monomers using a conjugated thiophene derivative, namely 3,5-diphenyldithieno[3,2-b:2′,3′-d]-thiophene (DDT) and one of the following compounds, namely diphenyliodonium hexafluorophosphate (Ph2I+PF6−), triphenylsulfonium hexafluorophosphate (Ph3S+PF6−) and N-ethoxy-2-methylpyridinium hexafluorophosphate (EMP+PF6−), as photosensitizer and coinitiator, respectively, was described. Polymerization occurred only when DDT, in the presence of the onium salts, was irradiated at wavelengths where the salts have no absorption. A feasible initiation mechanism involves intermolecular electron transfer from photoexcited thiophene compound to the onium salt. The relative initiation efficiencies of the salts were investigated and evaluated in terms of their redox potentials.

Syntheses and Electronic Properties of New Type of Donor–Acceptor Type Copolymers for Solar Cell Applications

GRAPHICAL ABSTRACT Abstract In this work, syntheses and properties of two copolymers comprising dithienothiophene (DTT) donor and benzo[c][2,1,3]thiadiazole (BTH) acceptor units have been described.

Synthesis and Characterization of Donor-Acceptor Copolymers Having Dithienophene – Benzothiadiazol Moieties Suitable for Use in Solar Cells

Since the discovery of conducting polymers, researches have been focused on the design and synthesis of new type polymers for development of novel conductive materials. Wynberg et al. have discovered donor-acceptor copolymers and this event has received a great deal of interest. The most important feature of these copolymers is that the band gaps are lowered because of the delocalization of π electrons over electron-donating and electron-accepting groups. For this purpose, several donor and acceptor groups were introduced and they have been concluded to be suitable for light emitting diodes (LEDs) and solar cells. Dithienothiophenes, comprising three fused thiophene rings, have a quite rich electronic structure and therefore, they are expected to show a donor-type behavior. Recently, better donor-type groups were discovered when compared to the ones in the past and their properties were investigated in terms of usability in solar cell applications. In this study, we have synthesized and characterized DTT-Btz-containing donor-acceptor copolymers.