Eintrag in der Universitätsbibliographie der TU Chemnitz
Volltext zugänglich unter
URN: urn:nbn:de:bsz:ch1-qucosa2-1048321
Ropero Hinojosa, Diego
Sommer, Michael (Prof. Dr.) ; Müller, Christian (Prof. Dr.) (Gutachter)
Synthesis and Characterization of Isatin-Benzodifuranone Copolymers for Thermoelectric Applications
Kurzfassung in englisch
Plastics are a key component of today's society. These types of materials are vastly used in many applications, ranging from packaging and consumer goods to advanced technologies such as electronics, energy storage, or biomedical devices. One special type of plastic is conjugated polymers. Conjugated polymers are macromolecules with an electronic structure possessing alternating single and double bonds. This special electronic configuration implies delocalization along the polymer backbone, which in turn confers on them special optoelectronic properties. This unique characteristic makes conjugated polymers great candidates as semiconductor materials, and they have therefore been widely explored for applications in organic electronics such as organic photovoltaics, field-effect transistors, and thermoelectric devices, where their tunable electronic structure and mechanical flexibility offer key advantages over traditional inorganic semiconductors. In this work, the chemical modification of various high-performing benzodifuranone (BDF)-isatin copolymers as n-type thermoelectric materials is presented. A new type of side chain containing a single-oxygen ether is developed and implemented in this type of polymers. This new approach offers a high tunability of the side chain, allowing modification not only of the branched alkyl residue, but also of the distance between the oxygen atom and the backbone in a simple synthetic approach. This new type of side chain delivers remarkable solubility in organic solvents up to 90 mg/mL, and also enhances the electrical conductivity of these polymers. Backbone modification is also presented as an efficient approach to reduce the lowest unoccupied molecular orbital (LUMO) energy of these polymers. Chlorination is determined as a synthetically simple strategy that can deliver LUMO reductions of circa -0.2 eV. The relationship between backbone modification and comonomer selection is further studied in terms of thermoelectric performance. It is shown that furan comonomers display the highest conductivities and air stabilities of all the polymers described. Underexplored synthetic pathways toward this type of polymers are also described. A new bisisatin monomer based on highly electron-deficient thiazolo[5,4-d]thiazole is prepared using metal-free open flask conditions. This new monomer is then copolymerized using aldol condensation with benzodifuranone, achieving a greener polymerization pathway. Covalent defects formed during this polymerization are thoroughly studied using model reactions with monofunctional substrates. Using this approach, several unexpected by-products could be identified and characterized. To further complement the study on defects, the polymers are imaged using scanning tunneling microscopy (STM), where defects found in the model reactions could be directly monitored. Finally, a new asymmetric monomer based on BDF is reported. This new asymmetric monomer is the putative compound of 6,6′-dibromoisoindigo with the substitution of a lactam by a lactone group. The new monomer is copolymerized with different donor comonomers with varying donor strength, and their optoelectronic properties are studied, indicating an effective asymmetry induction and a distinct morphology in comparison to their symmetric counterparts.
| Universität: | Technische Universität Chemnitz | |
| Institut: | Professur Polymerchemie | |
| Fakultät: | Fakultät für Naturwissenschaften | |
| Dokumentart: | Dissertation | |
| Betreuer: | Sommer, Michael (Prof. Dr.) | |
| DOI: | doi:10.60687/2026-0101 | |
| SWD-Schlagwörter: | Konjugierte Polymere , Polymerelektronik | |
| Freie Schlagwörter (Englisch): | Conjugated Polymers , Thermoelectric Materials , N-type Polymers , Organic Electronics , Side Chain Engineering | |
| DDC-Sachgruppe: | Chemie | |
| Sprache: | englisch | |
| Tag der mündlichen Prüfung | 07.05.2026 | |
| OA-Lizenz | CC BY 4.0 |
