Document Detail

Generation and recombination kinetics of optical excitations in poly(3-dodecylthienylenevinylene) with controlled regioregularity.
MedLine Citation:
PMID:  21916464     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Regioregularity in π-conjugated polymers is known to have desirable effects on chain organization in the solid state leading to improved characteristics for electronic device applications. In this report, we studied the photophysics of a new series of π-conjugated polymers, namely, poly(3-dodecylthienylenevinylene), with controlled regioregularity (PTV-CR), using the steady state photoinduced absorption (PIA), doping-induced absorption (DIA), thermally modulated absorption (TMA), and photoluminescence (PL) techniques in a broad spectral range, as well as Grazing incidence X-ray diffraction (GIXRD). PTV-CR has a low band gap of 1.65-1.70 eV from the most random PTV-5:5 to regular PTV-0:10. We have found that regioregularity affects optical properties of PTV-CR in different ways than in the case of well-studied poly(3-alkylthiophene). We discovered that even the most random PTV-5:5 shows submicrometer crystalline order, and there is no correlation between regioregularity and crystallinality. We found that PTV is intrinsically dark due to the reverse order of 1B(u) and 2A(g) excitons, with PL quantum efficiency ranging from 10(-5) to 2 × 10(-4). Spectroscopic data confirm the existence of long-lived neutral (triplets) and charged (polaron) excitations, and thus PTV is a unique nondegenerate ground state π-conjugated polymer which is intrinsically nonluminescent. The recombination mechanism and lifetime of such long-lived excitations are investigated through the pump intensity and pump frequency dependencies as well as temperature dependence of the sample. Increasing regioregularity is seen to reduce the thermal responsivity and intersystem crossing in these films. The novel, intrachain character of these effects and their implications for use of PTV derivatives for photovoltaic application are discussed.
Evan Lafalce; Xiaomei Jiang; Cheng Zhang
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Publication Detail:
Type:  Journal Article     Date:  2011-10-24
Journal Detail:
Title:  The journal of physical chemistry. B     Volume:  115     ISSN:  1520-5207     ISO Abbreviation:  J Phys Chem B     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-10     Completed Date:  2012-03-05     Revised Date:  2013-01-28    
Medline Journal Info:
Nlm Unique ID:  101157530     Medline TA:  J Phys Chem B     Country:  United States    
Other Details:
Languages:  eng     Pagination:  13139-48     Citation Subset:  -    
Department of Physics, University of South Florida, Tampa, Florida 33620, United States.
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Erratum In:
J Phys Chem B. 2012 Dec 6;116(48):14206

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