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Title: Thermochromism of a Poly(phenylene vinylene): Untangling the Roles of Polymer Aggregate and Chain Conformation

Abstract

We report reversible thermochromism of a conjugated polymer, poly{l_brace}2,5-bis[3-(N,N-diethylamino)-1-oxapropyl]-1,4-phenylenevinylene{r_brace} (DAO-PPV), in diluted solutions of toluene and 1,2-dichlorobenzene. By means of temperature- and solvent-dependent steady-state spectroscopy, picosecond time-resolved photoluminescence spectroscopy, and dynamic light scattering, we provide new insights into the role of polymer aggregates in defining the thermochromic behavior of PPVs. We find DAO-PPV to exhibit a low temperature state with vibronically structured red visible absorption and emission spectra. Structurally, this low temperature state is a densely packed and disordered polymer aggregate, which contains a fraction of well-ordered, packed polymer chains. These ordered regions serve as low energy trap sites for the more disordered regions in the aggregate, thus regulating the final emission of the aggregate and imposing a vibronically resolved emission spectrum, which is usually associated with emission from one or a few chromophores. The high temperature state of DAO-PPV is a loose aggregate, with structureless absorption and emission spectra in the green visible range. Structurally, the loose aggregate is a well-solvated aggregate retaining the physical dimension of the dense aggregate but for which interchain interactions are diminished with the increase of temperature. As a result, the spectroscopic behavior of the loose aggregate is very similar if not identical tomore » that of the single polymer chain. Increased solubility untangles polymer aggregates into single, dispersed, polymer chains, as we demonstrate here for DAO-PPV in 1,2-dichlorobenzene and at high temperature.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1040293
Report Number(s):
BNL-90993-2010-JA
Journal ID: ISSN 1520-6106; R&D Project: NC-001; KC020401H; TRN: US201210%%471
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B
Additional Journal Information:
Journal Volume: 113; Journal Issue: 50; Journal ID: ISSN 1520-6106
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; CHAINS; DIMENSIONS; EMISSION SPECTRA; LIGHT SCATTERING; PHOTOLUMINESCENCE; POLYMERS; SOLUBILITY; SPECTROSCOPY; TOLUENE

Citation Formats

Cotlet, M, Wang, C -C, Gao, Y, Shreve, A P, Zhong, C, Wang, L, Mudalige, K, and Wang, H -L. Thermochromism of a Poly(phenylene vinylene): Untangling the Roles of Polymer Aggregate and Chain Conformation. United States: N. p., 2009. Web.
Cotlet, M, Wang, C -C, Gao, Y, Shreve, A P, Zhong, C, Wang, L, Mudalige, K, & Wang, H -L. Thermochromism of a Poly(phenylene vinylene): Untangling the Roles of Polymer Aggregate and Chain Conformation. United States.
Cotlet, M, Wang, C -C, Gao, Y, Shreve, A P, Zhong, C, Wang, L, Mudalige, K, and Wang, H -L. 2009. "Thermochromism of a Poly(phenylene vinylene): Untangling the Roles of Polymer Aggregate and Chain Conformation". United States.
@article{osti_1040293,
title = {Thermochromism of a Poly(phenylene vinylene): Untangling the Roles of Polymer Aggregate and Chain Conformation},
author = {Cotlet, M and Wang, C -C and Gao, Y and Shreve, A P and Zhong, C and Wang, L and Mudalige, K and Wang, H -L},
abstractNote = {We report reversible thermochromism of a conjugated polymer, poly{l_brace}2,5-bis[3-(N,N-diethylamino)-1-oxapropyl]-1,4-phenylenevinylene{r_brace} (DAO-PPV), in diluted solutions of toluene and 1,2-dichlorobenzene. By means of temperature- and solvent-dependent steady-state spectroscopy, picosecond time-resolved photoluminescence spectroscopy, and dynamic light scattering, we provide new insights into the role of polymer aggregates in defining the thermochromic behavior of PPVs. We find DAO-PPV to exhibit a low temperature state with vibronically structured red visible absorption and emission spectra. Structurally, this low temperature state is a densely packed and disordered polymer aggregate, which contains a fraction of well-ordered, packed polymer chains. These ordered regions serve as low energy trap sites for the more disordered regions in the aggregate, thus regulating the final emission of the aggregate and imposing a vibronically resolved emission spectrum, which is usually associated with emission from one or a few chromophores. The high temperature state of DAO-PPV is a loose aggregate, with structureless absorption and emission spectra in the green visible range. Structurally, the loose aggregate is a well-solvated aggregate retaining the physical dimension of the dense aggregate but for which interchain interactions are diminished with the increase of temperature. As a result, the spectroscopic behavior of the loose aggregate is very similar if not identical to that of the single polymer chain. Increased solubility untangles polymer aggregates into single, dispersed, polymer chains, as we demonstrate here for DAO-PPV in 1,2-dichlorobenzene and at high temperature.},
doi = {},
url = {https://www.osti.gov/biblio/1040293}, journal = {Journal of Physical Chemistry B},
issn = {1520-6106},
number = 50,
volume = 113,
place = {United States},
year = {Thu Dec 17 00:00:00 EST 2009},
month = {Thu Dec 17 00:00:00 EST 2009}
}