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Approaches to low-bandgap polymer solar cells: using polymer charge-transfer complexes and fullerene metallocomplexesстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Zapunidi S.A., Martyanov D.S., Nechvolodova E.M., Tsikalova M.V., Novikov Yu N., Paraschuk D.Yu
- Журнал: Journal of Macromolecular Science - Pure and Applied Chemistry
- Том: 80
- Номер: 10
- Год издания: 2008
- Издательство: Marcel Dekker Inc.
- Местоположение издательства: United States
- Первая страница: 2151
- Последняя страница: 2161
- DOI: 10.1351/pac200880102151
- Аннотация: Polymer solar cells have shown high potential to convert solar energy into electricity in a cost-effective way. One of the basic reasons limiting the polymer solar cell efficiency is insufficient absorption of the solar radiation by the active layer that limits the photocurrent. To increase the photocurrent, one needs low-bandgap materials with strong absorption below 2 eV. In this work, we study two types of low-bandgap materials: ground-state charge-transfer complexes (CTC) of a conjugated polymer, MEH-PPV, and an exohedral metallocomplex of fullerene, (з2-C60)IrH(CO)[(+)DIOP] (IrC60). We demonstrate that the CTC formed between MEH-PPV and conjugated molecules with high electron affinity, namely 2,4,7-trinitrofluorenone (TNF) and 1,5-dinitroantraquinone (DNAQ), can have strong optical absorption extending down to the near infra-red. We have observed that the photoexcited CTC can generate free charges. We also report on optical studies of IrC60 as a possible acceptor for polymer/fullerene solar cells. IrC60 strongly absorbs in the visible spectral range, in particular in the red part, and therefore has a potential for increasing the photocurrent as compared with polymer/methanofullerene solar cells. Our studies of MEH-PPV/IrC60 blended films show that long-lived charges are efficiently generated at MEH-PPV upon photoexcitation of the blend. Polymer solar cells have shown high potential to convert solar energy into electricity in a cost-effective way. To date, the best polymer solar cells show the efficiency of solar energy conversion 4-5%, and significant efforts are underway to increase their efficiency to the level of practical applications. The working layer of polymer cells is a nanocomposite of soluble derivatives of a conjugated polymer and of a fullerene in which bulk heterojunction between them is formed. Two basic reasons are found to limit the polymer solar cell efficiency: insufficient absorption of the solar radiation (limiting the photocurrent) and loss of the photon energy during photoinduced charge separation in the bulk heterojunction (limiting the photovoltage). Therefore, to increase the photocurrent, one needs polymer or fullerene materials with strong absorption below 2 eV where usually conjugated polymers and fullerenes have low optical absorption. On the other hand, to increase the photovoltage, the energy difference between the corresponding frontier orbitals of the polymer and fullerene, e.g. LUMOs, should be decreased. In this work, to increase absorption of the solar cell active layer below 2 eV, we use two types of novel materials: Mulliken charge-transfer complexes (CTC) of conjugated polymer and metallocomplexes of fullerene. Moreover, the latter allow us to decrease essentially their electron affinity compared with the pristine fullerenes and, therefore, to decrease the energy loss in the photoinduced charge transfer. We show that the CTC formed between an archetypical conjugated polymer, MEH-PPV, and several conjugated molecules with high electron affinity can have strong optical absorption extending down to the near infra-red. We have observed that the CTC can generate free charges in a wide spectral range with the photosensitivity edge at 1 eV. We show that optical absorption of the fullerene metallocomplexes below 2 eV can be considerably higher than that of pristine fullerenes. We evaluate the efficiency of photoinduced charge transfer in blends of MEH-PPV with metallocomplex C60OsLn. We have observed that C60OsLn effectively quenches MEH-PPV photoluminescence and results in appearance of long-lived charged states (polarons) at MEH-PPV as follows from our photoinduced absorption spectroscopy data. Potentialities of conjugated polymer CTCs and fullerene metallocomplexes for organic solar cells are discussed.
- Добавил в систему: Паращук Дмитрий Юрьевич