Carrier dynamics of composite and nanolayered films of zinc phthalocyanine and C-60 measured by time-resolved terahertz spectroscopy

Date

2009-08-06

Author

Lane, Paul A.
Melinger, Joseph S.
Esentürk, Okan
Heilweil, Edwin J.

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We present a study of charge transfer and carrier dynamics in films of zinc phthalocyanine (ZnPc) and buckmisnsterfullerene (C-60) investigated by time-resolved terahertz spectroscopy (TRTS). These films are model structures for charge generation layers in organic photovoltaics and their intrinsic properties are therefore of interest. We compare two classes of films: composite films of ZnPc and C-60 prepared by co-evaporation and layered ZnPc/C-60 films prepared by alternating deposition. We find evidence for a short-lived charge transfer state of C-60 that decays within several picoseconds of excitation. In contrast, both composite and multi-layered films have a long-lived THz absorption that depends on the composition and structure of the fims. The optimum composition for charge transfer within composite films is a 1:1 blend of ZnPc and C-60. Amongst the layered films, there is an increase in charge photogeneration with decreasing layer thickness with a sample having ultrathin (2 nm) exhibiting the strongest THz absorption. A much stronger THz absorption signal was obtained from the layered structure than for the best composite film, even both structures contain similar fractions of ZnPc and C-60.

Subject Keywords

THz Spectroscopy, Phthalocyanine, Buckminsterfullerene, Organic photovoltaic

URI

https://hdl.handle.net/11511/35919

DOI

https://doi.org/10.1117/12.845719

Collections

Department of Chemistry, Conference / Seminar

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Citation Formats

P. A. Lane, J. S. Melinger, O. Esentürk, and E. J. Heilweil, “Carrier dynamics of composite and nanolayered films of zinc phthalocyanine and C-60 measured by time-resolved terahertz spectroscopy,” 2009, vol. 7416, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35919.