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Time-Resolved Terahertz Studies of Carrier Dynamics in P3HT and Zinc-Phthalocyanine/C60 Nanolayered Organic Films

Published

Author(s)

Edwin J. Heilweil, Paul A. Lane, Okan Esenturk, Paul D. Cunningham, Joseph S. Melinger

Abstract

Relative carrier mobilities in semiconducting organic polymer films measured using non-contact optical pump terahertz (THz) probe spectroscopy will be presented. Transient signal amplitude measurements of photo-injected mobility as a function of poly-3-hexylthiophene (P3HT) molecular weight correlate directly with electrical device test values, indicating that the THz method can be used as a rapid material screening approach. We also present measurements of P3HT and its bridged analog PBTTT conducting films as a function of structural regularity, dispersing solvent, addition of C60 electron traps, sample temperature and other growth parameters relevant to device manufacture. Photo-excitation dynamics in zinc phthalocyanine (ZnPc) and C60 nanolayers monitored from picoseconds to milliseconds by transient absorption and time-resolved terahertz spectroscopies (TRTS) is also discussed. Autoionization of C60 is a precursor to photocarrier generation while decay of the terahertz signal due to decreasing photocarrier mobility over the first 20 ps and thereafter reflects recombination dynamics. These dynamics transform from bimolecular to monomolecular as the layer thickness is reduced, revealing a metastable exciplex at the C60-ZnPc interface with a lifetime of 150 microseconds.
Proceedings Title
International Symposium on Frontiers in THz Technology (FTT 2012)
Conference Dates
November 27-29, 2012
Conference Location
Nara

Keywords

Photovoltaics, ZnPc-C60 nanolayers, P3HT, Time-Resolved Terahertz, Terahertz, carrier dynamics, solar energy

Citation

Heilweil, E. , Lane, P. , Esenturk, O. , Cunningham, P. and Melinger, J. (2012), Time-Resolved Terahertz Studies of Carrier Dynamics in P3HT and Zinc-Phthalocyanine/C60 Nanolayered Organic Films, International Symposium on Frontiers in THz Technology (FTT 2012), Nara, -1 (Accessed April 12, 2024)
Created October 19, 2012, Updated February 19, 2017