Solution processing is highly desirable for large area production of organic electronic devices. Film deposition from solution is usually performed at the kinetic crystallization regime in high throughput industrial fabrication processes. Attaining single crystals directly through solution printing remains challenging due to kinetic solvent evaporation, stochastic nucleation, and fluid flow instabilities during the printing process. Most solution processing techniques for fabricating single crystals operate at slow quasi-equilibrium conditions, rendering these methods undesirable for industrial applications. These challenges call for a better fundamental understanding of solution crystallization processes of organic semiconductors (OSCs) to allow the development of better solution processing methods for high-throughput fabrication of high performance electronic devices. In this project, supported by the Solid State and Materials Chemistry program, ways to control crystal nucleation and molecular packing will be obtained using a solution shearing (SS) platform as a model system. The parameters for controlled crystal growth from single nucleation sites and methods to obtain patterned single-crystalline domains will be investigated. Finally, a comprehensive understanding and approach will be developed for achieving patterned single-crystalline domains with desired molecular packing. Charge transport properties of the resulting films will be measured to characterize effects of morphology and molecular packing on charge transport. This work will develop fundamental understanding on tuning molecular packing and morphology in OSCs. This is essential for unprecedented performance and future large-scale production of organic electronics.
NON-TECHNICAL SUMMARY: Solution processing is highly desirable for large-area manufacturing of organic electronic devices. The proposed work will result in a systematic understanding of nucleation and growth in solution processing of organic semiconductors (OSCs). This is crucial for advancing the field of organic electronics, as well as, providing insights for future manufacturing of these devices (e.g. organic light emitting diodes, organic solar cells, transistors and sensors). The PI and student involved will work closely with the Stanford Office of Science Outreach Office to reach out to a broad population ranging from K-12, community college, undergraduate, and graduate students as well as prepare the teachers of tomorrow for new areas of science and technology. This research will expose both graduate students and undergraduates to a broad range of disciplines as well as a wide range of organic electronics technologies. Students will receive training on effective communication, a multidisciplinary approach to problem solving, thus, obtaining an impressive combination of technical engineering, basic scientific understanding, and communication skills. This research is also expected to support the development of interdisciplinary research in the United States and to promote public understanding of the impact of organic electronics on industrial and economic development.
