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.

–

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