- By:
- Keum, Jong K; Browning, James F; Xiao, Kai ; Shao, Ming ; Hong, Kunlun ; Halbert, Candice E
- Journal Name:
- Applied Physics Letters
- Page Number:
- 223301-223301
- Volume:
- 103
- Issue Number:
- 22
- Publication Date:
- November 25, 2013
- View DOI Listing:
- https://doi.org/10.1063/1.4836035
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.
