title: Synthesis and fluorescence characterization of MEHPPV oligomers.
abstract: Trimer, tetramer, and pentamer oligomers based on the polymer backbone structure of poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) have been synthesized by Horner-Wadsworth-Emmons reactions. The fluorescence spectra, emission quantum yields, and lifetimes of the oligomers have been characterized in dilute chloroform solutions. The oligomers exhibit a sequential increase in absorption and emission wavelength maxima and a decrease in fluorescence lifetime as the π conjugation length is increased. The shortening in excited state lifetime is shown to be due to an increase in the rates of both radiative and nonradiative processes. The absence of a mirror-image relationship for the absorption and fluorescence spectra of the oligomers is attributed to the photoexcitation of a range of torsional configurations followed by relaxation to a more planar arrangement that then emits.
authors: School of Chemistry and Bio 21 Institute, University of Melbourne, Victoria, Australia 3010.
authors: Andrew J
authors: AJ
authors: Tilley
authors: Stephen M
authors: SM
authors: Danczak
authors: Christine
authors: C
authors: Browne
authors: Timothy
authors: T
authors: Young
authors: Tina
authors: T
authors: Tan
authors: Kenneth P
authors: KP
authors: Ghiggino
authors: Trevor A
authors: TA
authors: Smith
authors: Jonathan
authors: J
authors: White