Solution-processed organic films are a facile route to high-speed, low cost, large-area deposition of electrically functional components (transistors, solar cells, emitters, etc.) that can enable a diversity of emerging technologies, from Industry 4.0, to the Internet of things, to point-of-use heath care and elder care. The extreme sensitivity of the functional performance of organic films to structure and the general nonequilibrium nature of solution drying result in extreme processing-performance correlations. In this Review, we highlight insights into the fundamentals of solution-based film deposition afforded by recent state-of-the-art in situ measurements of functional film drying. Emphasis is placed on multimodal studies that combine surface-sensitive X-ray scattering (GIWAXS or GISAXS) with optical characterization to clearly define the evolution of solute structure (aggregation, crystallinity, and morphology) with film thickness.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank Baskar Ganapathysubramanian for providing Figure 8, summarizing his group’s recent modeling. A.A. is grateful to the King Abdullah University for Science and Technology (KAUST) for funding and acknowledges support under the competitive funding schemes Faculty Initiated Collaboration, Academic Excellence Alliance (round 3), and Collaborative Research Grant (rounds 1 and 2). A.A. is also grateful for the SABIC Presidential Chair on solution-processed optoelectronic materials. Much of the work summarized required the excellent facilities and support at synchrotron sources around the world, including but not limited to the Diamond Light Source, the MPI-MF beamline at ANKA, the European Synchrotron Radiation Facility, beamline 7.3.3 of the Advanced Light Source (supported by the Director of the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract no. DE-AC02-05CH11231), and beamline D1 at the Cornell High Energy Synchrotron Source (supported by the National Science Foundation and NIH-NIGMS via NSF Grant DMR-1332208).