Dissociation processes of singlet and triplet excitons in organic photovoltaic cells

Zhihua Xu, Yue Wu, Bin Hu

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The dissociation processes of singlet and triplet excitons are studied based on fluorescent aluminum (III) 8-hydroxyquinoline (Alq 3) and phosphorescent fac-tris-(2-phenylpyridine) iridium [Ir(ppy) 3] molecules. We find that phosphorescent Ir(ppy) 3 shows a more efficient photovoltaic response as compared to fluorescent Alq 3. The short-circuit photocurrent action spectra and magnetic-field-dependent photocurrents reveal that the triplet excitons dissociate directly into free charge carriers at the metal-electrode interface while the singlet excitons experience bulk dissociation through polaron-pair states. This interface dissociation of triplet excitons forms a mechanism for phosphorescent organic materials to yield efficient photovoltaic responses.

Original languageEnglish (US)
Article number131116
JournalApplied Physics Letters
Volume89
Issue number13
DOIs
StatePublished - Oct 6 2006

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photovoltaic cells
excitons
dissociation
photocurrents
short circuits
organic materials
iridium
charge carriers
aluminum
electrodes
magnetic fields
metals
molecules

Cite this

Dissociation processes of singlet and triplet excitons in organic photovoltaic cells. / Xu, Zhihua; Wu, Yue; Hu, Bin.

In: Applied Physics Letters, Vol. 89, No. 13, 131116, 06.10.2006.

Research output: Contribution to journalArticle

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