Here, we report a novel method to determine the amount of pure, aggregated phase of donor and acceptor in organic photovoltaic (OPV) bulk heterojunctions. By determination of the diffraction intensity per unit volume for both donor and acceptor, the volume content of pure, aggregated donor and acceptor in the blend can be determined. We find that for the small molecule X2:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) system, in contrast to most polymer systems, all the PCBM is aggregated, indicating there is negligible miscibility of PCBM with X2. This provides an explanation why the performance of OPV devices of X2:PCBM are high over a large range of PCBM concentrations. This is in contrast to many other OPV blends, where PCBM forms a mixed phase with the donor and does not provide sufficient transport for electrons when the PCBM concentration is low. This study demonstrates that a mixed phase is not necessarily a requirement for good OPV device performance.
Oosterhout, Stefan D., et al. "Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics [On the Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics]." Chemistry of Materials, vol. 29, no. 7, Feb. 2017. https://doi.org/10.1021/acs.chemmater.7b00067
Oosterhout, Stefan D., Savikhin, Victoria, Zhang, Junxiang, Zhang, Yadong, Burgers, Mark A., Marder, Seth R., Bazan, Guillermo C., & Toney, Michael F. (2017). Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics [On the Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics]. Chemistry of Materials, 29(7). https://doi.org/10.1021/acs.chemmater.7b00067
Oosterhout, Stefan D., Savikhin, Victoria, Zhang, Junxiang, et al., "Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics [On the Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics]," Chemistry of Materials 29, no. 7 (2017), https://doi.org/10.1021/acs.chemmater.7b00067
@article{osti_1361065,
author = {Oosterhout, Stefan D. and Savikhin, Victoria and Zhang, Junxiang and Zhang, Yadong and Burgers, Mark A. and Marder, Seth R. and Bazan, Guillermo C. and Toney, Michael F.},
title = {Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics [On the Mixing Behavior in Small Molecule: Fullerene Organic Photovoltaics]},
annote = {Here, we report a novel method to determine the amount of pure, aggregated phase of donor and acceptor in organic photovoltaic (OPV) bulk heterojunctions. By determination of the diffraction intensity per unit volume for both donor and acceptor, the volume content of pure, aggregated donor and acceptor in the blend can be determined. We find that for the small molecule X2:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) system, in contrast to most polymer systems, all the PCBM is aggregated, indicating there is negligible miscibility of PCBM with X2. This provides an explanation why the performance of OPV devices of X2:PCBM are high over a large range of PCBM concentrations. This is in contrast to many other OPV blends, where PCBM forms a mixed phase with the donor and does not provide sufficient transport for electrons when the PCBM concentration is low. This study demonstrates that a mixed phase is not necessarily a requirement for good OPV device performance.},
doi = {10.1021/acs.chemmater.7b00067},
url = {https://www.osti.gov/biblio/1361065},
journal = {Chemistry of Materials},
issn = {ISSN 0897-4756},
number = {7},
volume = {29},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2017},
month = {02}}