Visualization of Hierarchical Nanodomains in Polymer/Fullerene Bulk Heterojunction Solar Cells

• Published in: Microscopy and microanalysis Vol. 20; no. 5; pp. 1507 - 1513
• Main Authors: Wen, Jianguo, Miller, Dean J., Chen, Wei, Xu, Tao, Yu, Luping, Darling, Seth B., Zaluzec, Nestor J.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.10.2014; Oxford University Press; Microscopy Society of America (MSA)
• Subjects: chromatic aberration correction; electron energy-loss spectroscopy; Energy loss; energy-filtered transmission electron microscopy; Fullerenes; Materials Applications; MATERIALS SCIENCE; Microscopy; Morphology; organic photovoltaics; Photovoltaics; Polymers; Solar cells; SOLAR ENERGY; X-ray energy-dispersive spectroscopy; United States > US; chromatic aberration correction; electron energy-loss spectroscopy; organic photovoltaics; energy-filtered transmission electron microscopy; X-ray energy-dispersive spectroscopy
• ISSN: 1431-9276; 1435-8115
• DOI: 10.1017/S1431927614001615

Traditional electron microscopy techniques such as bright-field imaging provide poor contrast for organic films and identification of structures in amorphous material can be problematic, particularly in high-performance organic solar cells. By combining energy-filtered corrected transmission electron microscopy, together with electron energy loss and X-ray energy-dispersive hyperspectral imaging, we have imaged PTB7/PC61BM blended polymer optical photovoltaic films, and were able to identify domains ranging in size from several hundred nanometers to several nanometers in extent. This work verifies that microstructural domains exist in bulk heterojunctions in PTB7/PC61BM polymeric solar cells at multiple length scales and expands our understanding of optimal device performance providing insight for the design of even higher performance cells.