skip to main content

DOE PAGESDOE PAGES

Title: How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms

Here, we study the excitonic coupling and homogeneous spectral line width of brick layer J-aggregate films. We begin by analysing the structural information revealed by the two-exciton states probed in two-dimensional spectra. Our first main result is that the relation between the excitonic couplings and the spectral shift in a two-dimensional structure is different (larger shift for the same nearest neighbour coupling) from that in a one-dimensional structure, which leads to an estimation of dipolar coupling in two-dimensional lattices. We next investigate the mechanisms of homogeneous broadening—population relaxation and pure dephasing—and evaluate their relative importance in linear and two-dimensional aggregates. Our second main result is that pure dephasing dominates the line width in two-dimensional systems up to a crossover temperature, which explains the linear temperature dependence of the homogeneous line width. This is directly related to the decreased density of states at the band edge when compared with linear aggregates, thus reducing the contribution of population relaxation to dephasing. Pump-probe experiments are suggested to directly measure the lifetime of the bright state and can therefore support the proposed model.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemistry; Max Planck Inst. for the Structure and Dynamics of Matter (MPSD), Hamburg (Germany)
  2. Max Planck Inst. for the Structure and Dynamics of Matter (MPSD), Hamburg (Germany)
  3. Univ. of Groningen (Netherlands). Zernike Inst. for Advanced Materials (ZIAM)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0001088; CHE-1112825; 627864
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 144; Journal Issue: 13; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); European Commission (EC); Joachim-Herz-Stiftung (Germany)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; nanomaterials; J-aggregates; pump probe experiments; Doppler effect; thin films; atomic spectral lines; delocalization; excitons; phonons; optical properties
OSTI Identifier:
1469696
Alternate Identifier(s):
OSTI ID: 1245892

Dijkstra, Arend G., Duan, Hong-Guang, Knoester, Jasper, Nelson, Keith A., and Cao, Jianshu. How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms. United States: N. p., Web. doi:10.1063/1.4944980.
Dijkstra, Arend G., Duan, Hong-Guang, Knoester, Jasper, Nelson, Keith A., & Cao, Jianshu. How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms. United States. doi:10.1063/1.4944980.
Dijkstra, Arend G., Duan, Hong-Guang, Knoester, Jasper, Nelson, Keith A., and Cao, Jianshu. 2016. "How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms". United States. doi:10.1063/1.4944980. https://www.osti.gov/servlets/purl/1469696.
@article{osti_1469696,
title = {How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms},
author = {Dijkstra, Arend G. and Duan, Hong-Guang and Knoester, Jasper and Nelson, Keith A. and Cao, Jianshu},
abstractNote = {Here, we study the excitonic coupling and homogeneous spectral line width of brick layer J-aggregate films. We begin by analysing the structural information revealed by the two-exciton states probed in two-dimensional spectra. Our first main result is that the relation between the excitonic couplings and the spectral shift in a two-dimensional structure is different (larger shift for the same nearest neighbour coupling) from that in a one-dimensional structure, which leads to an estimation of dipolar coupling in two-dimensional lattices. We next investigate the mechanisms of homogeneous broadening—population relaxation and pure dephasing—and evaluate their relative importance in linear and two-dimensional aggregates. Our second main result is that pure dephasing dominates the line width in two-dimensional systems up to a crossover temperature, which explains the linear temperature dependence of the homogeneous line width. This is directly related to the decreased density of states at the band edge when compared with linear aggregates, thus reducing the contribution of population relaxation to dephasing. Pump-probe experiments are suggested to directly measure the lifetime of the bright state and can therefore support the proposed model.},
doi = {10.1063/1.4944980},
journal = {Journal of Chemical Physics},
number = 13,
volume = 144,
place = {United States},
year = {2016},
month = {4}
}