Theoretical studies of optical absorption in low-bandgap polymers
Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesisAlternative title
Teoretiska studier av optisk absorption i polymerer med låga bandgap (Swedish)
The absorption spectra of a recently designed low-bandgap conjugated polymer has been studied using the semi-empirical method ZINDO and TDDFT/B3LYP/6-31G. The vertical excitation energies have been calculated for monomer up to hexamer. Two main absorption peaks can be seen, the one largest in wavelength corresponding to a HOMO to LUMO transition, and one involving higher order excitations. TDDFT results are red-shifted compared to the ZINDO results. Comparison with experiment yields that short conjugation lengths are dominating. This is possibly due to steric interactions between polymer chains, breaking the conjugation length. Such effects are also studied.
Place, publisher, year, edition, pages
Institutionen för fysik, kemi och biologi , 2005. , 44 p.
ZINDO, Density functional theory, Hartree Fock method, Low bandgap polymers, Absorption spectra, Semi empirical methods, Plastic solar cells
Other Physics Topics
IdentifiersURN: urn:nbn:se:liu:diva-4349ISRN: LiTH-IFM-EX--05/1498--SEOAI: oai:DiVA.org:liu-4349DiVA: diva2:20604