Julia W. P. Hsu is a Professor of Materials Science and Engineering in the Erik Jonsson School of Engineering and Computer Science of the University of Texas at Dallas (UT Dallas) and holds a Texas Instruments Distinguished Chair in Nanoelectronics. She received her BSE degree from Princeton University and M.S. and Ph.D. degrees from Stanford University. Prior to UT Dallas, she was Assistant and Associate Professor at the University of Virginia Physics Department (1993-1999), Member of Technical Staff at Bell Labs (1999-2003), and Principal Member of Technical Staff at Sandia National Laboratory (2003-2010). Hsu is a winner of a Hertz Foundation Fellowship (1985), the American Physical Society (APS) Apker Award (1986), a National Science Foundation Young Investigator Award (1993), and a Sloan Foundation Research Fellowship (1994). She was elected to Fellow of APS in 2001, American Association for the Advancement of Science (AAAS) in 2007, and Materials Research Society (MRS) in 2011. She was a co-chair for the Fall 2004 MRS meeting. She served as a Member-at-Large on the APS Division of Materials Physics Executive Committee (2004-2007), on the MRS Board of Directors (2005-2007), the Treasurer and Chair of Operation Oversight Committee for the MRS (2006-2007), chaired the MRS International Relations Committee from 2010-2011, and was on the Editorial Board of Solid State Communications. She currently serves on MRS Meeting Assessment Subcommittee. She has served on many external advisory committees, including Princeton University Center for Complex Materials, University of Massachusetts Energy Frontier Research Center, and Department of Energy Experimental Program to Stimulate Competitive Research (EPSCoR) at Idaho State University. She has published approximately 180 peer-reviewed journal papers and holds 5 patents.
Organic photovoltaic (OPV) devices represent promising technology for low cost, lightweight solar energy harvesting. The inexpensive, large-area manufacturing methods, e.g. roll-to-roll printing, favor solution deposition techniques. Due to the blended nature of the organic active layer in an OPV device, carrier transport layers at the active layer/electrode interface are necessary to set up the electric field across the device to extract electrons and holes. I will discuss solution synthesis of MoOx, WOx, NiOx, and CoOx nanoparticle suspensions for hole transport layer (HTL) in OPVs. To achieve a high built-in field, it is commonly believed that the HTL should have as high work function as possible. MoOx is commonly used as an inorganic HTL. I will discuss experimental and modeling results on unintentional doping arising from MoOx with excessively high work function. Both current-voltage (J-V) characteristics and external quantum efficiency (EQE) spectra are strongly affected by doping. I will then discuss criteria for ideal HTL materials, taking into account of work function, bandgap, conductivity, and carrier selectivity and show our efforts in adapting CuGaO2 and CuCrO2p-type delafossite materials for this purpose.