MSE Colloquium: Letian Dou, Solution Processed Semiconducting Polymers and Nanomaterials for Energy Harvesting

Department of Chemistry, UC-Berkeley; Materials Science Div., Lawrence Berkeley National Laboratory

Abstract

Solution-processed semiconductors show great promise in energy related applications owing to their synthetic variability, low-temperature processing, and the possibility of producing light-weight, mechanically flexible, environmental-friendly, and inexpensive electronics devices. Materials science plays a key role in connecting physics, chemistry, and engineering toward new materials with better performance. I have broad research interests in the fundamentals and applications of solution-processed organic and inorganic semiconductors for a variety of energy harvesting and electronic devices, including solar cells, photodetectors, light emitting diodes, etc.

In this talk, our rational design of low-bandgap conjugated polymers for organic photovoltaic will be discussed in the first half. By developing new organic building blocks, fine-tuning the molecular weight, solid-state packing and nano-scale thin film morphology, polymers with small optical bandgap, high charge carrier mobility, and high photovoltaic performance (with two record efficiencies) are obtained. However, the fundamental limitation of low charge carrier mobility in organic semiconductors is still there, probably due to the amorphous or semi-crystalline nature. To break the limitation, new materials with more ordered structure (higher degree of crystallinity) might be required. The other half of the presentation will be focusing on the fundamentals of crystalline polymers and inorganic perovskite nanostructures for the next generation solution-processed electronics.

Bio

Letian Dou obtained his B.S. in Chemistry from Peking University in 2009. He then joined Prof. Yang Yang’s group in the Department of Materials Science and Engineering at UCLA, and obtained his Ph.D. in 2014 (co-advised by Prof. Fred Wudl @UCSB during 2013). His doctoral research focused on the development of conjugated polymers for organic/hybrid photovoltaic applications. His research interest also includes the synthesis, characterization, and device application of small molecules, polymer single crystals, inorganic nanostructures, hybrid materials, and related optoelectronic devices. Currently, he is a Postdoc Fellow working with Prof. Peidong Yang at the University of California-Berkeley and Lawrence Berkeley National Laboratory. He has published 33 papers with more than 8000 citations. He is recipient of the MRS graduate student awards (2014) and the Link Foundation Energy Fellowship (2013-2015).