Effects of two types of chemical modifications on photoconducting polymers consisting of polyphenylene vinylene (PPV) derivatives are studied by static and ultrafast transient optical spectroscopy as well as semi-empirical ZINDO calculations. The first type of modification inserts 2,2′-bipyridyl-5-vinylene (bpyV) units in the PPV backbone, and the second type involves metal-chelation with the bpy sites. Photoluminescence (PL) and exciton dynamics of polymers 1 and 2 with PV:bpyV ratios of 1 and 3 were examined in solution, and compared with those of the homo-polymer, poly(2,5-bis(2′-ethylhexyloxy)-1,4-phenylene vinylene) (BEH-PPV). Similar studies were carried out for several metal-chelated polymers. These results can be explained by changes in π-conjugation throughout the polymer backbone. The attenuation in π-conjugation by the chemical modifications transforms a conducting polymer from one-dimensional semiconductor to molecular aggregates.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Polymers and Plastics