442828 The Effects of a P3HT Brush Functionalized Substrate in Organic Photovoltaics

Monday, November 9, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Elizabeth E. Bickel1, Jameson L. Tyler1, Sarah Russell1, Holly A. Stretz2, S. Michael Kilbey II3 and Mark Dadmun4, (1)Chemical Engineering, Tennessee Technological University, Cookeville, TN, (2)Department of Chemical Engineering, Tennessee Technological University, Cookeville, TN, (3)Departments of Chemistry and of Chemical and Biomolecular Engineering, University of Tennessee-Knoxville, Knoxville, TN, (4)Chemistry, University of Tennessee, Knoxville, TN

Organic photovoltaics (OPV’s) convert sunlight to electrical energy through a photoactive layer composed of a polymer electron donor, poly-3-hexylthiophene (P3HT) and a nanoparticle electron acceptor, phenyl-C61-butyric acid methyl ester (PCBM).

In this work the addition of a crystalline P3HT layer or “P3HT brush” was tested as a method for reducing PCBM agglomeration at the substrate. A P3HT brush was grafted onto the substrate prior to the deposition of a P3HT/PCBM bulk heterojunction (BHJ). Additionally, the effectiveness of Gas Expanded Polymer (GXP) annealing was tested for different pressure ranges (475-500 psi, 875-900 psi).

The Liquids Reflectometer (BL-4B) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) quantified the effects of the P3HT brush on PCBM dispersion. Neutron Reflectometry remains the only method currently which will distinguish between PCBM and P3HT on the nanoscale. Early results show that the addition of a P3HT brush had a small effect on PCBM dispersion. GXP annealing at the higher pressure range (875-900 psi) affected PCBM dispersion in the active layer to the greatest extent.

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