Seminar 10/15/2014 - Enrique Gomez, Pennsylvania State University: Fully Conjugated Block Copolymers for Organic Photovoltaics
Abstract: Organic electronic materials have the potential to impact almost every aspect of modern life including how we access information, light our homes, and power personal electronic devices. Unfortunately, weak intermolecular interactions and disorder at junctions of different organic materials limit the performance and stability of organic interfaces and hence the applicability of organic semiconductors to electronic devices. Our approach has focused on utilizing block copolymer architectures where critical interfaces are controlled and stabilized by covalent bonds to provide the hierarchical structure needed for high-performance organic electronics from self-assembled soft materials. For example, we have demonstrated control of donor-acceptor heterojunctions through microphase-separated conjugated block copolymers to achieve 3% power conversion efficiencies in non-fullerene photovoltaics. Characterization through X-ray scattering and electron microscopy reveals that the efficient performance of block copolymer solar cells is due to self-assembly into mesoscale lamellar morphologies with primarily face-on crystallite orientations. Although inferior in performance to inorganic and champion polymer/fullerene solar cells, the significant photovoltaic response of block copolymer devices provides the initial results needed to accelerate the development of next-generation materials. Incorporating the donor-acceptor interface within the molecular structure facilitates computational design efforts, such that we can utilize quantum calculations to predict charge transfer state energies near 1.8 eV for P3HT-based block copolymers and explain the unusually high open-circuit voltages of 1.2 V.
All seminars are held on Wednesdays from 12:00 noon-1:00 p.m. in the Bowen Hall Auditorium Room 222. A light lunch is provided at 11:30 a.m. in the Bowen Hall Atrium immediately prior to the seminar.
Location: Bowen Hall Auditorium
Date/Time: 10/15/14 at 12:00 pm - 10/15/14 at 1:00 pm
Category: PRISM/PCCM Seminar Series