Electroabsorption conjugated polymers

Horvath, A., H. Bassler, and G. Weiser. 1992. Electroabsorption in conjugated polymers. Phys Status Solidi 173 755-764. 

Liess, M., et al. 1997. Electroabsorption spectroscopy of luminescent and nonluminescent pi-conjugated polymers. Phys Rev B 56 15712-15724. 

Our goal is to model quantitatively 7r-electronic contributions to both vibrational and electronic spectra. The general e-ph analysis introduced in Section II combines the microscopic AM formalism [18,19] with the spectroscopic ECC model [22]. The reference force field F for PA provides an experimental identiHcation of delocalization effects. Transferable e-ph coupling constants are presented in Section III for polyenes and isotopes of trans- and a s-PA. The polymer force field in internal coordinates directly shows greater delocalization in t-PA, while coupling to C—C—C bends illustrates V(/ ) participation and different coupling constants a(/ a) and a(Jis) in Eq. (3) support an exponential r(/ ). NLO spectra of PDA crystals and films are presented in Section IV, with multiphoton resonances related to excited states of PPP models and vibronic contributions included in the Condon approximation. Linear and electroabsorption (EA) spectra of PDA crystals provide an experimental separation of vibrational and electronic contributions, and the full tt-tt spectrum is needed to model EA. We turn in Section V to correlated descriptions of electronic excitations, with particular attention to theoretical and experimental evidence for one- and two-photon thresholds of centrosymmetric backbones. The final section comments on parameters for conjugated polymers, extensions, and open questions. 

Anderson et al. synthesized the soluble conjugated porphyrin polymer of 5,10,15,20-diethylnyl zinc porphyrin (DEtyP)n using Glaser-Hay coupling (Figure 34). The real and imaginary components of / (—0,0, to) of the.se polymers were calculated from the electroabsorption spectra. The / (-m 0,0, (o) on the order of 7.3 x 10 esu was obtained at the peak resonance due to resonance enhancement. 

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