New didecyloxyphenylene-acceptor alternating conjugated copolymers: Synthesis, properties, and optoelectronic device applications
Journal
Macromolecules
Journal Volume
41
Journal Issue
19
Pages
6952-6959
Date Issued
2008
Author(s)
Abstract
Seven donor-acceptor copolymers incorporating didecyloxyphenylene (DP) donor and the following acceptors-thieno[3,4-b]pyrazine (TP), 2,1,3-benzothiadiazole (BT), quinoxaline (Q), pyridine (Py), 2,3-dimethyl-5,7-ditnien-2-yl-thieno[3,4-b]pyrazine (DTTP), 4,7-dithien-2-yl-2, 1,3-benzothiadiazole (DTBT), and 2,3-dimethyl-5,7-dithien-2-yl-quinoxaline (DTQ)-were synthesized by Suzuki coupling polymerization. The effects of the acceptor strength and backbone planarity on the optical, electrochemical, field-effect charge transport, and photovoltaic properties of the donor-acceptor copolymers were investigated. The optical band gap (eV) of the copolymers showed the trend of DP/TP (1.47) < DP/BT (2.37) < DP/Py (2.76) < DP/Q (2.78) < DP/P (3.15). The DP/TP copolymer had a field-effect hole mobility of 1.89 × 10-3 cm2 V-1 s-1. The DP/DTBT and DP/DTQ copolymers showed hole mobilities of 1.92 × 10 -4 and 2.10 × 10-3 cm2 V-1 s-1, respectively. The strong acceptor strength of TP and coplanar backbone in the DP/TP copolymer resulted in a large intramolecular charge transfer, leading to the observed charge transport and optical properties. These results show that the backbone planarity of the DP/BT and DP/Q copolymers was significantly improved by incorporating thiophene moieties, leading to enhanced charge transport. Photovoltaic cells fabricated from DP/DTBT and DP/DTQ polymers blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) showed power conversion efficiencies of 0.40-0.41% under AM 1.5 solar simulator illumination (100 mW/cm2). The results of the present study show that the electronic and optoelectronic properties of dialkoxylphenylene-based donor-acceptor copolymers could be tuned through the acceptor structure and backbone coplanarity. © 2008 American Chemical Society.
SDGs
Other Subjects
Acceptor strengths; Alternating conjugated copolymers; Benzothiadiazole; Butyric acid methyl esters; Charge transports; Coplanarity; Electrochemical; Intramolecular charge transfers; Optical; Optical bands; Optoelectronic properties; Photovoltaic properties; Planarity; Pyrazine; Quinoxaline; Solar simulators; Suzuki couplings; Acids; Charge transfer; Conversion efficiency; Copolymerization; Copolymers; Electrochemical properties; Esters; Fatty acids; Hole mobility; Ion exchange; Monomers; Optical properties; Optoelectronic devices; Organic compounds; Organic polymers; Photovoltaic effects; Plastic products; Polymers; Solar energy; Solar power generation; Sulfur compounds; Thiophene; ABS resins
Type
journal article