In situ characterization methods for evaluating microstructure formation and drying kinetics of solution-processed organic bulk-heterojunction films

Abstract

Recently, in situ characterization methods have attracted increasing attention, especially in organic photovoltaics (OPV) field, since they provide greater insight into the mechanism of film formation, thus help to identify optimized processing conditions used to process the most efficient organic bulk-heterojunction thin films. In combination with various powerful X-ray-based characterization methods, several studies observed the morphological changes under the influence of different processing conditions. In this review, we summarize the fundamentals and implementation of X-ray-based and optical characterization methods, utilized in in situ mode and introduce the reader a better overview of the information acquired from a given technique in terms of microstructure formation in OPV. While we give a chronological development of in situ characterization methods in the field of OPV, we discuss the interplay between thermodynamics of solutions and drying kinetics of different types of organic blends.

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ACKNOWLEDGMENT

The authors gratefully thank Deutsche Forschungsgemeinschaft (DFG) in the framework of SFB 953 (Synthetic Carbon Allotropes) and Cluster of Excellence ‘Engineering of Advanced Materials’ and GRK 1896 In situ Microscopy with Electrons, X-rays and Scanning Probes.

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Güldal, N.S., Kassar, T., Berlinghof, M. et al. In situ characterization methods for evaluating microstructure formation and drying kinetics of solution-processed organic bulk-heterojunction films. Journal of Materials Research 32, 1855–1879 (2017). https://doi.org/10.1557/jmr.2017.190

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