Oligomeric dithienopyrrole-thienopyrrolodione (DTP-TPD) donor-acceptor copolymer for organic photovoltaics
Subtitle: preprint
By: Scott R. Hammond ... [et al.].
Contributors: Hammond, Scott R.; National Renewable Energy Laboratory (U.S.)
Series: NREL/CP -- 5200-50660; Conference paper (National Renewable Energy Laboratory (U.S.)) -- 5200-50660.
Publisher: National Renewable Energy Laboratory
Published: 2011
Place of publication: Golden, CO]
Language: eng
Format: [electronic resource] :
Subjects: Photovoltaic power generation; Oligomers; Copolymers; Polymeric composites
Description: A new donor-acceptor copolymer system based upon a dithienopyrrole (DTP) donor moiety and a thienopyrrolodione (TPD) accepting moiety has been designed and synthesized for organic photovoltaic (OPV) applications. The TPD accepting moiety has recently gained significant attention in the OPV community and is being incorporated into a number of different polymer systems. In contrast, the DTP donor moiety has received only limited attention, likely due in part to synthetic difficulties relating to the monomer. In our hands, the bis(trimethyltin)-DTP monomer was indelibly contaminated with ~5% of the mono-destannylated DTP, which limited the Stille polymerization with the dibromo-TPD monomer (>99% pure) to produce material with Mn ~ 4130 g/mol (PDI = 1.10), corresponding to around eight repeat units. Despite this limitation, UV-visible absorption spectroscopy demonstrates strong absorption for this material with a band gap of ~1.6 eV. Cyclic voltammetry indicates a highest occupied molecular orbital (HOMO) energy level of -5.3 eV, which is much lower than calculations predicted. Initial bulk heterojunction OPV devices fabricated with the fullerene acceptor phenyl C61 butyric acid methyl ester (PCBM) exhibit Voc ~ 700 mV, which supports the deep HOMO value obtained from CV. These results suggest the promise of this copolymer system.
Notes: Title from title screen (viewed July 27, 2011).

"July 2011."

"Presented at the 37th IEEE Photovoltaic Specialists Conference (PVSC 37), Seattle, Washington, June 19-24, 2011."

Includes bibliographical references (p. 4).

DE-AC36-08GO28308

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