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The spectroscopic properties of poly(3,4-ethylenedithiathiophene) (PEDTT) which is a sulfur analogue of poly(3,4-ethylenedioxythiophene) (PEDOT) are studies by in situ techniques like IR, Vis and electron spin resonance (ESR) spectroelectrochemistry. Despite the topological equivalence of PEDTT and PEDOT, their IRAV signatures are found to be different and the results suggest very different conformations for the two materials.

Research has been conducted on the soluble C (sub)60 -(pi-conjugated oligomer) dyads. The synthesis of these dyads has been carried out and the results indicate that in the resulting electro- and photoactive dyads the singlet-singlet energy transfer and the intramolecular electron transfer compete with each other in the photoexcited oligomer deactivation.

The electrochemical redox processes of poly(dithieno[3,4-b:2E,2E-d]thiophene)(pDTT3) are reported based on the attenuated total reflection Fourier transform infrared studies. Vibrational spectroscopic studies are carried for this low band gap conjugated polymer with a polythiophene-like backbone, where an aromatic moiety is fused to each thiophene ring, in situ during electrochemical oxidation and reduction.

The photoinduced charge-transfer properties of a series of polyalkylthiophene copolymers, carrying anthraquinone substituents covalently linked to the conjugated backbone, are analyzed in the solid state by photoinduced absorption (PA) and light-induced electron spin resonance (LESR) spectroscopy. The results have showed that in these polymers, the number of acceptor substituents in the chain, easily tuned by chemical tailoring, plays a vital role in the photoexcitation scenario.

A regiospecific {[2-methoxy-5-[(3,7-dimethyloctyl)oxy]phenylene]vinylene} (MDMO-PPV) copolymer was synthesized with improved charge transport properties by taking advantage of sulfinyl precursor note. The improved charge transport properties of the novel regiospecific MDMO-PPV copolymer was used in the fabrication of bulk heterojunction solar cells exhibiting an improved power conversion efficiency of 2.65 per cent with high (0.71) high filling factor.

Near-steady-state photoinduced absorption (PIA) and photoluminescence studies are presented on photoinduced electron transfer reactions from poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and poly[3-(2-(3-methylbutoxy)ethyl)thiophene] (P3MBET) as donors (D) onto a homologous series of tetracyano-p-quinodimethane (TCNQ) derivatives containing fused aromatic rings as acceptors (A) to systematically study the effect of acceptor electron affinity. We observe that composite films of these D/A couples give rise to long-lived charge separated states upon photoexcitation, as evidenced from the formation of polaron bands (radical cation absorption) in the PIA and the concomitant loss of the metastable triplet PIA and photoluminescence that are observed in pristine MEH-PPV and P3MBET. We find that the efficiency of the photoinduced electron transfer reaction correlates with the reduction potential of the acceptors. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We present near-steady-state photoinduced absorption (PIA), photoluminescence, and light-induced electron spin resonance (LESR) studies on photoinduced electron transfer reactions from poly(bis-2,5-epi-cholestanoxy-1,4-phenylene vinylene) (BeCHA-PPV) as a donor to Buckminsterfullerene (C60) and a number of functionalized fullerenes as acceptors. We show that functionalized fullerenes with a solubilizing side chain linked to C60 in a [5,6] (fulleroid) or [6,6] (methanofullerene) fashion, are efficient electron acceptors towards BeCHA-PPV, as evidenced from changes in the PIA, the efficient quenching of the photoluminescence, and the LESR spectra of BeCHA-PPV cation and fullerene anion radicals. The increased miscibility of the functionalized fullerenes with the conjugated polymer as compared to C60, can be important for the preparation of future electrooptic devices, based on the photoinduced charge separation. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Photoinduced charge transfer and energy transfer reactions are examined using a new cyano-substituted naphthalene-vinylene type conjugated polymer. Optical absorption and emission spectra of thin films of mixtures of this polymer with the fullerene derivative exhibit interesting features indicating photoinduced charge transfer.

Doping-induced reactions in conjugated polymers are studied by spectroelectrochemical techniques. The results on reduction reactions (n-doping) of the conjugated ladder polymer polybenzimidazobenzophenanthroline (BBL) are reported.