Tailoring Aggregation of Thiophene-Based Polymers Using Solvent and Solvent Additives
| dc.contributor.advisor | Newayemedhin Aberra | |
| dc.contributor.author | Werkitu Geremew | |
| dc.date.accessioned | 2025-08-17T22:33:09Z | |
| dc.date.available | 2025-08-17T22:33:09Z | |
| dc.date.issued | 2024-11-15 | |
| dc.description.abstract | With an emphasis on P3HT and P1TI, this thesis examines how H and J aggregation affects the photophysical characteristics and charge production mechanisms in donor-acceptor (D-A) copolymers. Because of their promising charge transport and exciton mobility properties, these polymers are especially interesting for organic optoelectronic devices, such as organic photovoltaics (OPVs) and organic lightemitting diodes (OLEDs). But there is still a lack of thorough knowledge on how aggregation behavior affects their optical and electrical characteristics, especially when it comes to the effects of solvent conditions and high boiling point additives on the aggregation mechanisms of H and J. The copolymers were produced and deposited as thin films on cleaned glass substrates using thiophene-based derivatives as donor components and isoindigo as acceptor. Several solvents, including 1,2-dichlorobenzene (o-DCB), were used to create the films. chloroform (CF), selected according to their polarity and refractive indices.Higher A00/A01 and I00/I01 ratios in both P3HT and P1TI demonstrated that o-DCB promoted J-aggregation, according to experimental results. This led to better chain ordering and exciton delocalization, both of which are advantageous for charge transfer in OPVs. On the other hand, CF encouraged H-aggregation, which resulted in less exciton mobility and more localized exciton states. It was discovered that adding the high boiling point additive DIO improved charge separation, decreased H-aggregation, and increased J-aggregation—all of which are essential for increasing device efficiency. Additionally, the study discovered that P1TI displayed greater crystallinity whereas P3HT displayed a larger Stokes shift, suggesting increased disorder in the excited states of P3HT. This implies that P1TI might work better in applications that benefit from lower reorganization energy. These findings provide important information about how to modify solvent conditions and additives to regulate aggregation behavior, which optimizes material characteristics for organic electron. | |
| dc.identifier.uri | https://etd.aau.edu.et/handle/123456789/6909 | |
| dc.language.iso | en_US | |
| dc.publisher | Addis Ababa University | |
| dc.subject | Tailoring Aggregation | |
| dc.subject | Thiophene-Based Polymers | |
| dc.subject | Solvent and Solvent Additives | |
| dc.title | Tailoring Aggregation of Thiophene-Based Polymers Using Solvent and Solvent Additives | |
| dc.type | Thesis |