The electronic states of polyfluorene copolymers with alternating donor-acceptor units

Summary, in English

We calculate the electronic states of the low bandgap polyfluorene-based copolymer DiO-PFDTBT, which consists of alternating 9,9-dioctyl-9H-fluorene and 4,7-di-thiophen-2-ylbenzo[1,2,5]thiadiazole (TBT) units, and compare with the steady-state absorption, emission, and excitation spectrum. Using the semiempirical quantum-chemical (ZINDO) method we can assign the characteristic bands of the "camel-back" absorption spectrum to one charge transfer state at lower energy localized on the TBT unit, and one delocalized excitonic state at higher energy corresponding to the -conjugated electron system. Additional "dark" charge transfer states in the gap between these bands have been revealed. Calculations are also made on the red light emitting polyfluorene-based copolymer poly(fluorene-co-benzothiadiazole) (F8BT), which contains benzo[1,2,5]thiadiazole instead of TBT. The nature of the electronic states in F8BT and DiO-PFDTBT are found to be qualitatively the same. ©2004 American Institute of Physics.

• Author: Kim Jespersen; Wichard Beenken; Yuri Zausjitsyn; Arkady Yartsev; Mats Andersson; Tönu Pullerits; Villy Sundström
• Department/s: Chemical Physics
• Publishing year: 2004
• Language: English
• Pages: 12613-12617
• Publication/Series: Journal of Chemical Physics
• Volume: 121
• Issue: 24
• Links: http://dx.doi.org/10.1063/1.1817873
• Document type: Journal article
• Publisher: American Institute of Physics (AIP)
• Topic: Atom and Molecular Physics and Optics
• Status: Published
• ISBN/ISSN/Other: ISSN: 0021-9606