In der vorliegenden Arbeit wird die Synthese linearer und zyklischer Aminoketone via nucleophiler aromatischer Substitution von fluorsubstituierten aromatischen Ketonen mit sekundären, aliphatischen Diaminen vorgestellt. Durch eine Adaption der Prozessparameter konnte eine elegante Methode zur Synthese fluorendgruppentragender Oligomere sowie von definierten Makrozyklen entwickelt werden. Die Modifizierung der Oligomere erfolgte sowohl durch Endgruppensubstitution als auch durch Reaktionen an der Carbonylgruppe am Oligomerrückgrat. Als Funktionalisierungsreagenzien wurden Mercaptoessigsäure, LAWESSONs Reagenz und N,N-Dimethylanilin eingesetzt. Die Umsetzung der Makrozyklen mit N,N-Dialkylanilinen ermöglicht die Synthese zyklischer Triphenylmethanfarbstoffe. Die Untersuchung der optischen Eigenschaften dieser zyklischen Kristallviolett-Derivate in Abhängigkeit des pH-Wertes und der Natur des Lösungsmittels sowie der Sensitivität gegenüber Cyanid-Ionen erfolgte mit Hilfe der UV/Vis-Spektroskopie.

Herein, we present a quasi-living Negishi-type catalyst-transfer polycondensation of a zinc–organic DTSbased monomer which provides an access to narrowly distributed poly(4,4-bis(2-ethylhexyl)dithieno[3,2-b:20,30-d]silole (PDTS) with controlled molecular weight. The synthesis of well-defined all-conjugated diblock copolymers containing a PDTS block was accomplished by a combination of Kumada and Negishi catalyst-transfer polycondensations (KCTP and NCTP, respectively). Particularly, it was shown that living P3HT chains obtained by KCTP of magnesium–organic thiophene-based monomer efficiently initiate NCTP of zinc–organic DTS-based monomer. The purity of the DTS-based monomer was found to be a crucial factor for achieving a clean chain-growth polymerization process. A combination of physico-chemical methods was used to prove the success of the block copolymerization.

We performed an in-depth study of high molecular weight poly[3,6-(dithiophene-2-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene] P(DPP2OD-TT) synthesized through the Stille coupling polycondensation in order to understand the correlation between molecular weight, processing conditions and charge transport. We observed a rapid increase in its aggregation in solution with increasing molecular weight which strongly limits the solubility and processability for weight average molecular weights beyond 200 kg mol⁻¹. This results in severe limitation in the charge transport properties of the polymer. We further observe the presence of bulk electronic defects in all different polymer batches that severely limit the current flow and manifest themselves in organic field effect transistors as apparent charge density dependence of the mobility. These defects are passivated by exposure to an ambient atmosphere, as confirmed by an increase in current and mobility that is no more charge density dependent. This is further confirmed by the result of chemical doping using 2,2-(perfluoronaphthalene-2,6-diylidene)dimalononitrile, F₆TCNNQ, which leads to the filling of the trap states and a higher charge density independent mobility of up to 1 cm2 V⁻¹ s⁻¹.

Organic semiconducting polymers are widely employed in organic electronics such as organic photovoltaics (OPVs), organic field-effect transistors (OFETs) and organic light emitting diodes (OLEDs). Their remarkable mechanical and charge transport properties as well as solution processability allow low-cost fabrication of light-weight and flexible devices. Among them indacenodithiophene (IDT)-based materials are promising candidates for application in organic electronics. Due to their low energetic disorder, extended conjugation and high electron density the IDT-based polymers show high field-effect mobilities and high absorption coefficients. However, their synthesis suffers from long reaction sequences and is often accomplished using toxic materials. Commercialization requires development of more efficient and sustainable reaction pathways to ease tailoring of structures and to limit molecular defects. Herein, the development of new synthetic pathways towards IDT-based polymers is presented in which all C-C coupling steps are achieved by C-H activation – an atom-economic alternative to conventional transition-metal catalyzed cross couplings. Two different strategies were established to synthesize a series of well-defined IDT-based homo- and copolymers with different side chain patterns and varied molecular weights. The first way starts by synthesis of a precursor polymer and subsequent cyclization affording IDT homopolymers. In the second approach, cyclized IDT monomers were prepared first and then polymerized using direct arylation polycondensation (DAP) yielding IDT homo- and copolymers. The synthetic pathways were optimized in terms of maximizing molecular weights and limiting defect structures. While the first pathway enables synthesis of well-defined homopolymers, the latter is the method of choice for preparation of IDT-based copolymers in high yields and adjustable molecular weights. The polymers were further characterized in detail by optical, thermal, electrical and morphological analyses. OFETs as well as all-polymer solar cells (all-PSCs) were fabricated to investigate the influence of structural modifications and molecular weight on their optoelectronic performance. Thus, this thesis provides a comprehensive study of the structure-property correlations of IDT-based polymers and simplified synthetic protocols for the design and preparation of donor-acceptor copolymers in the future.