Electroabsorption spectra of push-pull porphyrins in solution and in solid films

Kamlesh Awasthi, Hung Yu Hsu, Hung Chu Chiang, Chi Lun Mai, Chen Yu Yeh, Eric Wei Guang Diau, Nobuhiro Ohta*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Polarized electroabsorption (E-A) spectra of highly efficient porphyrin sensitizers (YD2 and YD2-oC8) have been measured in benzene solution. Polarized E-A spectra of these push-pull porphyrins embedded in poly(methyl methacrylate) films or sensitized on TiO2 films are also observed. Based on the analysis of the E-A spectra, the magnitude of the electric dipole moment both in the ground state and in the lowest excited state have been evaluated in solution and in solid films. The electric dipole moment in the excited state of these compounds is very large on TiO2 films, suggesting the interfacial charge transfer on TiO2 surface following photoexcitation of porphyrin dyes. The electric dipole moment in the excited state evaluated from the E-A spectra is very different from the one evaluated from the electrophotoluminescence spectra on TiO2, suggesting that the strong local field of TiO2 films is applied to the fluorescing dyes attached to TiO2 films.

Original languageEnglish
Pages (from-to)527-534
Number of pages8
JournalJournal of Porphyrins and Phthalocyanines
Volume19
Issue number1-3
DOIs
StatePublished - 1 Jan 2015

Keywords

  • Stark shift
  • dye-sensitized solar cell
  • electric dipole moment
  • push-pull porphyrins

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