ABSTRACT Theoretical and experimental studies of poly(p-phenylene vinylene) (PPV) polymers and oligomer of MPV were discussed and summarized. From the absorption spectra, several excitation bands of PPV were observed and a clear feature of vibronic coupling could be identified in the fluorescence. While in MPV oligomer, effects of displacement as well as distortion of potential surfaces are revealed from the asymmetry between absorption and emission. However, in PPV polymers, the dynamics of excitation and de-excitation processes are different, as seen by comparing the spectral feature between photoluminescence (PL), photoluminescence-excitation (PLE) and absorption spectra, which are drastically different. In the theoretical study, the ground and excited electronic structures of PPV were calculated using oligomers with different lengths. Results from exciton theory and molecular orbital theory were compared. The vibronic feature in the experimental spectra can be attributed to the benzene-ethylene vibrational motion as obtained from ab-initio molecular calculations. Molecular theory of absorption spectra was used to calculate the different spectra of PPV. Electronic structures of excited state were calculated by the configuration interaction (CI) method using semi-empirical INDO/S Hamiltonian. By combining molecular theory of absorption and molecular calculations through a proper kinetic model for PPV systems, the spectra can be simulated and the nature of radiative processes can be established.
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