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Title: Tailorable Exciton Transport in Doped Peptide–Amphiphile Assemblies

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.

Authors:
 [1];  [1];  [1];  [2];  [1];  [1]
  1. Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
  2. Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1427541
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 11; Journal Issue: 9; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
diffusion; doping; excimer; exciton; nanofiber; peptide; self-assembly

Citation Formats

Solomon, Lee A., Sykes, Matthew E., Wu, Yimin A., Schaller, Richard D., Wiederrecht, Gary P., and Fry, H. Christopher. Tailorable Exciton Transport in Doped Peptide–Amphiphile Assemblies. United States: N. p., 2017. Web. doi:10.1021/acsnano.7b03867.
Solomon, Lee A., Sykes, Matthew E., Wu, Yimin A., Schaller, Richard D., Wiederrecht, Gary P., & Fry, H. Christopher. Tailorable Exciton Transport in Doped Peptide–Amphiphile Assemblies. United States. https://doi.org/10.1021/acsnano.7b03867
Solomon, Lee A., Sykes, Matthew E., Wu, Yimin A., Schaller, Richard D., Wiederrecht, Gary P., and Fry, H. Christopher. 2017. "Tailorable Exciton Transport in Doped Peptide–Amphiphile Assemblies". United States. https://doi.org/10.1021/acsnano.7b03867.
@article{osti_1427541,
title = {Tailorable Exciton Transport in Doped Peptide–Amphiphile Assemblies},
author = {Solomon, Lee A. and Sykes, Matthew E. and Wu, Yimin A. and Schaller, Richard D. and Wiederrecht, Gary P. and Fry, H. Christopher},
abstractNote = {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.},
doi = {10.1021/acsnano.7b03867},
url = {https://www.osti.gov/biblio/1427541}, journal = {ACS Nano},
issn = {1936-0851},
number = 9,
volume = 11,
place = {United States},
year = {2017},
month = {8}
}