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Functional Materials for Energy Applications

Speaker

Prof. Jung-Kun Lee, Department of Mechanical Engineering and Materials Science, University of Pittsburgh

Education

- 09/2000 Ph.D. in Materials Science & Engineering, Seoul National University, Korea

             Dissertation: Investigation of the ferroelectric property of Pb-base oxides by controlling the domain configuration and the crystal structure

             Advisor: Professor Kung Sun Hong

- 02/1996 M.S. in Inorganic Materials Engineering, Seoul National University, Korea

             Dissertation: Morphotrophic phase boundary and dielectric properties of (Na1/2Bi1/2)TiO3-PbZrO3 solid solutions

             Advisor: Prof. Kug Sun Hong

- 02/1994 B.S. in Inorganic Materials Engineering, Seoul National University, Korea

Professional Experience

- 05/2018-present William Kepler Whiteford Professor, Department of Mechanical Engineering and Materials Science, University of Pittsburgh, USA

- 09/2013-04/2018 Associate Professor and William Kepler Whiteford Faculty Fellow, Department of Mechanical Engineering and Materials Science, University of Pittsburgh, USA

- 03/2015-present Adjunct Professor, Department of Energy Science, Sungkyunkwan University, Korea

- 03/2013-02/2014 Adjunct Professor, WCU-Program, Seoul National University, Korea

- 09/2007-08/2013 Assistant Professor, Department of Mechanical Engineering and Materials Science, University of Pittsburgh, USA

- 01/2005-08/2007 Technical Staff Member, Materials Science and Technology Division, Los Alamos National Laboratory, USA

- 01/2002-12/2004 Director’s Funded Post-doctor, Materials Science and Technology Division, Los Alamos National Laboratory, USA

- 09/2000-12/2001 Senior Researcher, Research Institute of Advanced Materials, Seoul National University, Korea

| Date | Monday, November 29th, 2021

| Time | 16:00 ~ 17:00

| Venue | 33동 315호 (관해세미나실)

            줌링크: https://us05web.zoom.us/j/88579576501?pwd=ZWd6MWp6aW1hNk44c2ZwRVJUNlc3Zz09

            회의 ID: 885 7957 6501  암호: mse

Abstract

To meet the increasing demand for energy and also address a concern about global warming, it is essential to explore electric and optical properties of functional materials and find a way to harness renewable energy and reduce energy consumption of existing devices. In this presentation, I will introduce functional materials that are being studied at the University of Pittsburgh to resolve energy issues. 

In the first part of the presentation, I will show our recent studies on stable halide perovskite solar cells (PSCs). One issue in PSCs is how to make a hole transport layer reliable and reproducible. Our recent results show that the thermally oxidized Ni film can be an excellent hole transport layer of PSCs and the residual stress in NiO film is an important parameter to control the carrier recombination of PSCs.  The other issue of PSCs is degradation of the perovskite layer in humid and hot environment. My group has demonstrated that the stability of PSCs in humid environment is greatly enhanced by facile coating of polymer-nanoparticle composites. Interpenetrating polymer chains and embedded nanoparticles changes the surface wettability and makes a twisted path for water permeation.

In the second part of the presentation, I will show new materials design for energy-efficient memory devices. One emerging application of the halide perovskite is the resistive random-access memory (ReRAM) as a promising next-generation nonvolatile memory device. My group reports the asymmetric resistive switching of the halide perovskite film. Schottky barrier induced by TiO2 interfacial layer exhibits lower current at high resistive switching state and larger space charge polarization, which could be useful to ReRAM application. The other material of interest for memory devices is layered compounds of Aurivillius phase, Bi5FeTi3O15. Regardless of multiferroic property and high Curie temperature, it has several inherent problems such as high leakage current, small polarization, and large coercive field. Our recent comprehensive analysis shows how to resolve this problem. Cr doping significantly changes the electric, dielectric, and ferroelectric properties of Bi5FeTi3O15 by reducing the lattice aspect ratio and changing the grain shape.

Dr. Jung-Kun Lee is William Kepler Whiteford Professor in the Department of Mechanical Engineering and Materials Science at the University of Pittsburgh (Pitt). He also serves as the Graduate Program Coordinator for Materials Science and Engineering. After he completed his PhD degree in Materials Science and Engineering at Seoul National University, he worked at Los Alamos National Laboratory as Director’s Funded Postdoctoral Fellow and Technical Staff Member. In 2007, he joined Pitt in 2007, In his career, he has published ~190 papers in refereed academic journals and 1 textbook on electric, magnetic and optical materials. The scientific quality of his research is validated by >7,000 citations and h-index of 46 (Google Scholar). His research focuses on electronic and energy- related materials with the emphasis on 1) renewable energy devices (photovoltaics, photoelectrochemical devices, and fuel cells), 2) material processing of electronic, optical and magnetic materials. He received an NSF career award in 2009 and his research has been supported through NSF, NRC, DOE, DoD, Pennsylvania Government, and international collaborative projects.

| Host | Prof. Jin-Young Kim (02-880-8315)