Identification of the Possible Defect States in Poly(3-hexylthiophene) Thin Films

ORAL

Abstract

We find evidence for a gradual change in the electronic properties of regioregular poly(3-hexylthiophene) thin films with temperature. The conduction properties appears to be mediated by hopping conduction dominated by a low density of defects states within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap, not by a change in band gap. The possible origins of a low density of defects states within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap are suggested. A number of ``chemical'' defects, impurities and structural defects can contribute to features in photoemission for regioregular poly(3-hexylthiophene). A density of states within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap may affect the transport properties of regioregular poly(3-hexylthiophene) and like polymers. These gap electronic states are not expected in the perfectly ordered polymer.

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Authors

  • Danqin Feng

    • University of Nebraska-Lincoln Dept. of Physics and Astronomy
    • University of Nebraska-Lincoln

  • Tony Caruso

    • Center for Nanoscale Science and Engineering, North Dakota State University
    • Center for Nanoscale Science and Engineering
    • North Dakota State University
    • CNSE

  • Yaroslav Losovyj

    • Center for Advanced Microstructures and Devices, Louisiana State University
    • Louisiana State University

  • Douglas Schulz

    • North Dakota State University

  • Peter Dowben

    • Department of Physics and Astronomy, University of Nebraska-Lincoln
    • Physics and Astronomy, University of Nebraska at Lincoln, Lincoln, NE
    • University of Nebraska-Lincoln