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Title: The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions

Abstract

Formation, relaxation and dynamics of polarons and methanofullerene anion radicals photoinitiated in poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′-benzothiadiazole)]:-[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCDTBT:PC{sub 61}BM) bulk heterojunctions were studied mainly by light-induced EPR (LEPR) spectroscopy in wide photon energy and temperature ranges. Some polarons are pinned by spin traps whose number and depth are governed by the composite morphology and photon energy. The proximity of the photon energy and the polymer bandgap reduces the number of such traps, inhibits recombination of mobile charge carriers, and facilitates their mobility in polymer network. Spin relaxation and charge carrier dynamics were studied by the steady-state saturation method at wide range of temperature and photon energy. These processes were shown to be governed by spin exchange as well as by the photon energy. Charge transfer in the composite is governed by the polaron scattering on the lattice phonons of crystalline domains embedded into amorphous polymer matrix and its activation hopping between polymer layers. The energy barrier required for polaron interchain hopping exceeds that of its intrachain diffusion. Anisotropy of polaron dynamics in the PCDTBT:PC61BM composite is less than that of poly(3-alkylthiophenes)-based systems that evidences for better ordering of the former. Lorentzian shape of LEPR lines of both charge carriers,more » lower concentration of spin traps as well as behaviours of the main magnetic resonance parameters were explained by layer ordered morphology of polymer matrix.« less

Authors:
; ;  [1]
  1. Kinetics and Catalysis, Institute of Problems of Chemical Physics, Chernogolovka 142432 (Russian Federation)
Publication Date:
OSTI Identifier:
22419967
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANISOTROPY; BUTYRIC ACID; ELECTRON SPIN RESONANCE; FULLERENES; PHOTONS; POLYMERS; SPECTROSCOPY; SPIN; SPIN EXCHANGE; TEMPERATURE RANGE

Citation Formats

Krinichnyi, V. I., E-mail: kivirus@gmail.com, Yudanova, E. I., and Denisov, N. N. The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions. United States: N. p., 2014. Web. doi:10.1063/1.4890995.
Krinichnyi, V. I., E-mail: kivirus@gmail.com, Yudanova, E. I., & Denisov, N. N. The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions. United States. doi:10.1063/1.4890995.
Krinichnyi, V. I., E-mail: kivirus@gmail.com, Yudanova, E. I., and Denisov, N. N. Mon . "The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions". United States. doi:10.1063/1.4890995.
@article{osti_22419967,
title = {The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions},
author = {Krinichnyi, V. I., E-mail: kivirus@gmail.com and Yudanova, E. I. and Denisov, N. N.},
abstractNote = {Formation, relaxation and dynamics of polarons and methanofullerene anion radicals photoinitiated in poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′-benzothiadiazole)]:-[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCDTBT:PC{sub 61}BM) bulk heterojunctions were studied mainly by light-induced EPR (LEPR) spectroscopy in wide photon energy and temperature ranges. Some polarons are pinned by spin traps whose number and depth are governed by the composite morphology and photon energy. The proximity of the photon energy and the polymer bandgap reduces the number of such traps, inhibits recombination of mobile charge carriers, and facilitates their mobility in polymer network. Spin relaxation and charge carrier dynamics were studied by the steady-state saturation method at wide range of temperature and photon energy. These processes were shown to be governed by spin exchange as well as by the photon energy. Charge transfer in the composite is governed by the polaron scattering on the lattice phonons of crystalline domains embedded into amorphous polymer matrix and its activation hopping between polymer layers. The energy barrier required for polaron interchain hopping exceeds that of its intrachain diffusion. Anisotropy of polaron dynamics in the PCDTBT:PC61BM composite is less than that of poly(3-alkylthiophenes)-based systems that evidences for better ordering of the former. Lorentzian shape of LEPR lines of both charge carriers, lower concentration of spin traps as well as behaviours of the main magnetic resonance parameters were explained by layer ordered morphology of polymer matrix.},
doi = {10.1063/1.4890995},
journal = {Journal of Chemical Physics},
number = 4,
volume = 141,
place = {United States},
year = {Mon Jul 28 00:00:00 EDT 2014},
month = {Mon Jul 28 00:00:00 EDT 2014}
}