Abstract
Understanding the origin for the film stratification of electron donor/acceptor blend is crucial for high efficiency organic photovoltaic cell. In this study, P3HT:PCBM blend is deposited onto hydrophilic and hydrophobic substrate to examine the film stratifications. The neutron reflectivity results show that, on the different surfaces, PCBM diffuses toward the two interfacial regions in an identical fashion during thermal annealing. This evidences that the film stratification is not affected by the substrates. Instead, since P3HT remains more amorphous in the interfacial regions and PCBM is miscible with amorphous P3HT, PCBM preferentially diffuses to the interfacial regions, resulting in the stratification.
Original language | English |
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Article number | 223301 |
Journal | Applied Physics Letters |
Volume | 103 |
Issue number | 22 |
DOIs | |
State | Published - Nov 25 2013 |
Funding
This research was conducted at the Spallation Neutron Source (SNS) and the Center for Nanophase Materials Sciences (CNMS), which are sponsored at Oak Ridge National Laboratory by the Office of Basic Energy Sciences, U.S. Department of Energy. NR measurements were performed on the Liquids Reflectometer at the Spallation Neutron Source, Oak Ridge National Laboratory. Discussion with Dr. John F. Ankner of SNS was very useful in the data analysis.