Tailorable Exciton Transport in Doped Peptide-Amphiphile Assemblies

Lee A. Solomon, Matthew E. Sykes, Yimin A. Wu, Richard D Schaller, Gary P. Wiederrecht, H. Christopher Fry

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Light-harvesting biomaterials are an attractive target in photovoltaics, photocatalysis, and artificial photosynthesis. Through peptide self-assembly, complex nanostructures can be engineered to study the role of chromophore organization during light absorption and energy transport. To this end, we demonstrate the one-dimensional transport of excitons along naturally occurring, light-harvesting, Zn-protoporphyrin IX chromophores within self-assembled peptide-amphiphile nanofibers. The internal structure of the nanofibers induces packing of the porphyrins into linear chains. We find that this peptide assembly can enable long-range exciton diffusion, yet it also induces the formation of excimers between adjacent molecules, which serve as exciton traps. Electronic coupling between neighboring porphyrin molecules is confirmed by various spectroscopic methods. The exciton diffusion process is then probed through transient photoluminescence and absorption measurements and fit to a model for one-dimensional hopping. Because excimer formation impedes exciton hopping, increasing the interchromophore spacing allows for improved diffusivity, which we control through porphyrin doping levels. We show that diffusion lengths of over 60 nm are possible at low porphyrin doping, representing an order of magnitude improvement over the highest doping fractions.

Original languageEnglish
Pages (from-to)9112-9118
Number of pages7
JournalACS Nano
Volume11
Issue number9
DOIs
Publication statusPublished - Sep 26 2017

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Keywords

  • diffusion
  • doping
  • excimer
  • exciton
  • nanofiber
  • peptide
  • self-assembly

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Solomon, L. A., Sykes, M. E., Wu, Y. A., Schaller, R. D., Wiederrecht, G. P., & Fry, H. C. (2017). Tailorable Exciton Transport in Doped Peptide-Amphiphile Assemblies. ACS Nano, 11(9), 9112-9118. https://doi.org/10.1021/acsnano.7b03867