Aggregation Effects on the Emission Spectra and Dynamics of Model Oligomers of MEH-PPV

• DOI: 10.1021/jp904308h
• Publication Date: 2009-10-05T16:54:46Z
• Authors: Gizelle A. Sherwood; Ryan Cheng; Timothy M. Smith; James H. Werner; Andrew P. Shreve; Linda A. Peteanu; Jurjen Wildeman
• Keywords: Oligomer; J-aggregate

The effects of aggregate formation on the photophysical properties oligomers MEH-PPV were studied in bulk solution to better understand aggregation emission polymer. Nanoaggregates from 3 17 repeat units length formed using a solvent reprecipitation method. spectra are not readily modeled classical dipole−dipole coupling picture interchain interactions. A strong dependence photophysics oligomer chain is also observed. Short-chain produce nanoaggregates with absorption and essentially identical those monomer. Long-chain form aggregates having more strongly perturbed fluorescence decreased yields. In these aggregates, size 0−0 band relative that vibronic replicates sensitive function precipitation conditions. Their lifetimes wavelength dependent. These trends explained terms core−shell model postulates existence "single-chain-like" "aggregate-like" emitters within single aggregate.