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Calamatic liquid crystal blends for organic photovoltaics

Kelly, Stephen M.; Lei, Chunghong; Al Khalifah, Manea S.; O'Neill, Mary; Aldred, Matthew P.; Kitney, Stuart P.; Vlachos, Panagiotis; Kelly, Stephen M.


Stephen M. Kelly

Chunghong Lei

Manea S. Al Khalifah

Mary O'Neill

Matthew P. Aldred

Stuart P. Kitney

Panagiotis Vlachos


Zakya H. Kafafi

Paul A. Lane


Four different perylene-based electron-acceptors having similar electron affinities, but different thermotropic phases are blended with nematic liquid crystalline electron-donors with a fluorene-thiophene structure to form single layer photovoltaic devices. Best results are obtained when the nematic donor is mixed with an amorphous acceptor to give a supercooled nematic glass at room temperature. Atomic force microscopy operating in the phase contrast mode reveals phase separation on a nanometer scale with a broad distribution of domain sizes peaking at 26 nm. We correlate the morphology of the different blends with the performance of the photovoltaic devices. Power conversion efficiencies up to 0.9 % are obtained with excitation at 470 nm.

Presentation Conference Type Conference Paper (unpublished)
Publication Date Aug 28, 2008
Journal Proceedings of SPIE - The International Society for Optical Engineering
Print ISSN 0277-786X
Publisher Society of Photo-optical Instrumentation Engineers
Peer Reviewed Peer Reviewed
Volume 7052
Article Number 705214
Pages 0 - 0
APA6 Citation Lei, C., Al Khalifah, M. S., O'Neill, M., Aldred, M. P., Kitney, S. P., Vlachos, P., & Kelly, S. M. Calamatic liquid crystal blends for organic photovoltaics. Paper presented at Organic Photovoltaics IX
Keywords Organic photovoltaics, bulk heterojunction, liquid crystals, organic semiconductors, atomic force microscopy