IMRI Seminar: Molecular Design for Reliable Organic Electronics

Abstract: Narrow bandgap conjugated small molecules and polymers are drawing significant attention in organic electronics, especially organic solar cells. An inevitable fact is that intrinsic advantages and disadvantages of these two classes of materials relevant to solution-processable photovoltaics are often contrary. In particular, small molecules possess structural monodispersity and higher crystallinity but with poorer film formation properties and lower thermal stabilities in the solid state compared to their polymeric counterparts. More importantly, solar cells based on small molecules are extremely sensitive to chemical impurities, whereas polymers are relatively more tolerant. The polydispersity of polymers significantly complicates the interpretation of solid state structure, resulting in poor practices toward satisfactory device application under real-world circumstances. This seminar will focus on how molecular frameworks can be designed to utilize some of the most important features of both polymers (e.g., film quality and thermal robustness) and small molecules (e.g., structural monodispersity and crystallinity) to enable organic electronic devices to be more tolerant to bulk composition, processing conditions and environmental variability, considerations that are essential for practical flexible electronics.

Bio: Xiaofeng Liu is currently principal scientist leading the materials team at Carbon Nanotube Technologies developing carbon nanotube-based flexible electronics. He is also a founding partner at NovaTeq Solutions, a technology consulting firm specialized in OLED display and touch sensors. From 2015 to 2017, Liu served as the technical lead at Polyradiant Corporation, a UCLA-based startup, commercializing silver nanowire-based touch sensors and OLED lighting panels. Prior to joining the startup world, Liu was a project scientist at UC Santa Barbara, where he managed a research lab of more than 20 members and led independent research projects and collaborations. His research interests include organic semiconductors, functional composite materials and flexible integrated electronics.

Liu earned his bachelor's degree in medicinal chemistry from Peking University (2004) and a doctorate in materials chemistry from the Chinese Academy of Sciences with a P&G Doctoral Award (2009). He received postdoc training from UC Santa Barbara (2012). Xiaofeng has authored and coauthored more than 45 peer-reviewed publications and is an editor of Heliyon, an open-access Elsevier journal, in the areas of semiconducting materials and devices.

Host: Xiaoqing Pan