Düsseldorf, Universiẗat, Diss., 2000.

Mainz, Universiẗat, Diss., 2003.

Oldenburg, University, Diss., 2004. / Dateien in unterschiedlichen Formaten.

Düsseldorf, Universiẗat, Diss., 2004.

The following low bandgap conducting polymers have been prepared by electrochemical polymerisation of the corresponding monomers: poly-4Hcyclopenta[2,1-b; 3,4-b']dithiophene-4-one, (PCDT), poly-4-dicyanomethylene-4Hcyclopenta[2,1-b: 3,4-b']dithiophene (PCDM) and 6,8-di(2-cyano-2(2- thienyl))ethenyl-4(ethylenedioxy)-4H-cyclopenta[2,1-b; 3,4-b' ]dithiophene (PCET). The polymers were characterised by cyclic voltammetry, spectroelectrochemical studies and impedance measurements in order to assay their suitability as active materials in high power supercapacitors. The redox switching of the polymers from neutral to doped states and the charge capacity of the films was studied by cyclic voltammetry. The results showed that only PCDM and PCET underwent efficient p- and n- doping which is a prerequirement for type III supercapacitors. The electrochemical switching is accompanied by changes to the optical properties of the polymers which has been examined by spectroelectrochemical measurements. In situ UV-visible spectroscopy indicated that the polymers possessed a low bandgap (< 2 eV) and suggested that they adopt a quinoid structure during doping.

Ulm, Univ. Diss., 2006.

Universiẗat, Diss., 2000--München.

Techn. Universiẗat, Diss., 2002--Dresden.

Organic electrode materials, as sustainable and environmental benign alternatives to inorganic electrode materials, show great promise for achieving cheap, light, versatile and disposable devices for electrical energy storage applications. Conducting redox polymers (CRPs) are a new class of organic electrode materials where the charge storage capacity is provided by the redox chemistry of functional pendent groups and electronic conductivity is provided by the doped conducting polymer backbone, enabling the production of energy storage devices with high charge storage capacity and high power capability. This pendant-conducting polymer backbone combination can solve two of the main problems associated with organic molecule-based electrode materials, i.e. the dissolution of the active material and the sluggish charge transport within the material. In this thesis, diethyl terephthalate and polythiophenes were utilized as the pendant and the backbone, respectively. The choice of pendant-conducting polymer backbone combination was based on potential match between the two moieties, i.e. the redox reaction of terephthalate pendent groups and the n-doping of polythiophene backbone occur in the same potential region. The resulting CRPs exhibited fast charge transport within the polymer films and low activation energies involved charge propagation through these materials. In the design of these CRPs an unconjugated link between the pendant and the backbone was found to be advantageous in terms of the polymerizability of the monomers and for the preservation of individual redox activity of the pendants and the polymer chain in CRPs. The functionalized materials were specifically designed as anode materials for energy storage applications and, although insufficient cycling stability was observed, the work presented in this thesis demonstrates that the combination of redox active functional groups with conducting polymers, forming CRPs, shows promise for the development of organic matter-based electrical energy storage materials.

In this study, two kinds of homopolymers (PPDOT, and P3HT), and three different proportions of copolymers (PPDOT-co-P3HT=1:1, PPDOT-co-P3HT=3:1, and PPDOT-co-P3HT=1:3) have been synthesized successfully by Grignard metathesis. PDOT and 3HT, which are both of monomers, are electron-donating. Due to the fact that PDOT was caused larger than 3HT by pushing effect, it can change the conjugation length to be much longer, resulting in lower energy level of HOMO, and thus reduce energy gap of high molecular. These polymers possess optical bandgaps in the range of 1.908 to 1.922 eV. The desirable absorption attributes of these materials make them to be the excellent candidates for use in organic solar cells. In this study, the analysis and discussion of these polymers were measured by TGA, DSC, XRD, GPC, NMR, UV, PL, and AC-2 for thermal stability, crystallinity, structure and optical properties. From the XRD, materials of main chain ordered are well crystalline, which can increase the absorption of thiophene ring. By UV, we could find absorption region of infrared light increase that is beneficial to enhance ISC, but led to lower HOMO, and thus reduced VOC. However, the overall device power conversion efficiencies indicate that increasing ISC is much greater than decreasing VOC. Hence, power conversion efficiency increased. However, in PL, intensity of the emission is large, and it will cause components to quenching that lead to reduce its efficiency. We knew HOMO-LUMO energy level matching relations of polymer materials which were mixed with PCBM as the active layer of organic solar cells by UV-VIS and AC-2. From the instructions of device power conversion efficiency, because efficiency is not high, it causes the short circuit. The reason is (1) energy level can not match (2) the solubility of PPDOT is not very good, hence the film is not easy even. The way to improve is to identify a better solvent to increase its solubility.