Charge transfer reactions in nematic liquid crystals

Gary P. Wiederrecht, Michael R Wasielewski, Tamar Galili, Haim Levanon

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

Ultrafast transient absorption studies of intramolecular photoinduced charge separation and thermal charge recombination were carried out on a molecule consisting of a 4-(N-pyrrolidino)naphthalene-l,8-imide donor (PNI) covalently attached to a pyromellitimide acceptor (PI) dissolved in the liquid crystal 4'-(n-pentyl)-4-cyanobiphenyl (5CB). The temperature dependencies of the charge separation and recombination rates were obtained at temperatures above the nematic-isotropic phase transition of 5CB, where ordered microdomains exist and scattering of visible light by these domains is absent. We show that excited state charge separation is non-adiabatic, and obtain the unexpected result that charge separation is dominated by molecular reorientation of 5CB perpendicular to the director within the liquid crystal microdomains. We also show that charge recombination is adiabatic and is controlled by the comparatively slow collective reorientation of the liquid crystal microdomains relative to the orientation of PNI+-PI. We also report the results of time resolved electron paramagnetic resonance (TREPR) studies of photoinduced charge separation in a series of supramolecular compounds dissoved in oriented liquid crystal solvents. These studies permit the determination of the radical pair energy levels as the solvent reorganization energy increases from the low temperature crystalline phase, through the soft glass phase, to the nematic phase of the liquid crystal.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsI.C. Khoo
Pages102-111
Number of pages10
Volume3475
DOIs
Publication statusPublished - 1998
EventLiquid Crystals II - San Diego,CA, United States
Duration: Jul 20 1998Jul 21 1998

Other

OtherLiquid Crystals II
CountryUnited States
CitySan Diego,CA
Period7/20/987/21/98

Fingerprint

Nematic liquid crystals
polarization (charge separation)
Liquid crystals
Charge transfer
liquid crystals
charge transfer
retraining
imides
Naphthalene
Excited states
naphthalene
Crystal orientation
Temperature
Electron energy levels
Paramagnetic resonance
electron paramagnetic resonance
Phase transitions
energy levels
Scattering
Crystalline materials

Keywords

  • Charge Transfer
  • Liquid Crystals
  • Solvation Dynamics

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Wiederrecht, G. P., Wasielewski, M. R., Galili, T., & Levanon, H. (1998). Charge transfer reactions in nematic liquid crystals. In I. C. Khoo (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (Vol. 3475, pp. 102-111) https://doi.org/10.1117/12.326896

Charge transfer reactions in nematic liquid crystals. / Wiederrecht, Gary P.; Wasielewski, Michael R; Galili, Tamar; Levanon, Haim.

Proceedings of SPIE - The International Society for Optical Engineering. ed. / I.C. Khoo. Vol. 3475 1998. p. 102-111.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Wiederrecht, GP, Wasielewski, MR, Galili, T & Levanon, H 1998, Charge transfer reactions in nematic liquid crystals. in IC Khoo (ed.), Proceedings of SPIE - The International Society for Optical Engineering. vol. 3475, pp. 102-111, Liquid Crystals II, San Diego,CA, United States, 7/20/98. https://doi.org/10.1117/12.326896
Wiederrecht GP, Wasielewski MR, Galili T, Levanon H. Charge transfer reactions in nematic liquid crystals. In Khoo IC, editor, Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3475. 1998. p. 102-111 https://doi.org/10.1117/12.326896
Wiederrecht, Gary P. ; Wasielewski, Michael R ; Galili, Tamar ; Levanon, Haim. / Charge transfer reactions in nematic liquid crystals. Proceedings of SPIE - The International Society for Optical Engineering. editor / I.C. Khoo. Vol. 3475 1998. pp. 102-111
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