Phase separation with solvent evaporation in a AB-block-copolymer.

1. Carrier Mobility and Exciton Diffusion in Disordered Organic SemiconductorsThuc-Quyen Nguyen, University of California-Santa Barbara, DMR 1035480 Our goal is to use mathematical tools to understand and ultimately predict the various materials properties that influence the function of organic solar cells. - We continue to fine tune a theoretical method to predict charge carrier mobility in disordered organic semiconductors by including carrier traps. We have applied the method to estimate the hole mobilities in molecular donors and confirmed the results with experimental measurements. Our approach will streamline current trial and error synthetic methods. - A first-principles approach without empirical input is used to determine exciton diffusion length, lifetime, and diffusivity in disordered polymers, which agree very well with experiments. Chemical structure and processing conditions can affect exciton diffusion length. The proposed approach could guide rational design of organic optoelectronic materials. - We have developed a method to model phase separation using Cahn-Hilliard with degenerate diffusion and to model the solvent evaporation process in a polymer blend. This approach is crucial for studying of polymer blend morphologies and could guide rational design of new solar cell materials. Spinodal decomposition of a polymer blend modeled by Cahn-Hilliard with degenerate diffusion. Phase separation with solvent evaporation in a AB-block-copolymer.

2. Carrier Mobility and Exciton Diffusion in Disordered Organic SemiconductorsThuc-Quyen Nguyen, University of California-Santa Barbara, DMR 1035480 • New collaborations • 1) Dr. Michael F. Toney (Stanford Synchrotron Radiation Laboratory) • 2) Prof. Maria Antonietta Loi (University of Groningen, The Netherlands) • 3) Prof. Ifor Samuel (University of St Andrews, UK) • 4) Prof. Paul WM Blom (Max Planck Institute for Polymer Research, Germany) • 5) Prof. Hector Ceniceros (UCSB) • Education/outreach • - Nguyen and Bazan organized UCSB laboratory visit for Ventura High School students and teachers. • - Gang helped organize a summer camp for high-school teachers on nano-science and computational materials science. • - Garcia-Cervera developed a new graduate-level course on molecular modeling and Density Functional Theory in the Mathematics department at UCSB. • - The PIs at UCSB mentored 3 undergraduate students this year. Please insert an image or group of images here to illustrate your broader impacts activities. If you need more space, you may reduce the adjacent textbox. Please use lettering that is clearly visible (i.e. not too small). Please include a brief figure caption. PLEASE DO NOT EXCEED 1 MB PER SLIDE. High school teacher workshop held in CSUN in April 2012. Gang gave a lecture on introduction to organic solar cells and some results in modeling effort.