Presentation title: “Recent Developments in Piezoelectric Materials”
Presenter: Prof. Wenwu Cao
Time: 9:00-10:30 am, July 30, 2018
Location: Conference Room at the 14th floor of the Underwater Acoustic Engineering Building
Short Bio of the presenter:
Wenwu Cao received the bachelor’s degree in theoretical physics from Jilin University in January 1982 and was selected to study in the United States. He received his doctorate degree in condensed matter physics from Pennsylvania State University in the United States in May 1987. He worked as a postdoctoral fellow in the Materials Research Institute of Pennsylvania State University and Physics Department of Cornell University. In 1990, he was employed as an assistant professor and assistant researcher in the Department of Materials and the Materials Research Institute of Pennsylvania State University. In 1993, he was promoted as an associate professor and associate researcher. He joined the Department of Mathematics in 1995 as an associate professor in the Department of Mathematics and the Institute of Materials Research, and in 2001, he became a lifelong professor in the Department of Mathematics and the Institute of Materials Research of Pennsylvania State University, as well as a professor in the Department of Biological Engineering and the Department of Materials Engineering. In 2006, he was appointed as a Changjiang Distinguished Professor of the Ministry of Education at Harbin Institute of Technology. In 2009, he was selected as the second batch of national experts of the “Thousand Talents Program”. In 2011, he was appointed as the director of the Institute of Cohesive Science and Technology of Harbin Institute of Technology and concurrently served as a doctoral supervisor in biomedical engineering at the College of Life Sciences of Harbin Institute of Technology.
Professor Wenwu Cao has been engaged in interdisciplinary research and teaching for many years. His main research interests are functional materials and their applications, especially the theory of ferroelectric materials, the preparation of piezoelectric materials and the design of ultrasonic transducers, the development of ultrasonic devices, and the research and development of methods and instruments for medical acoustics and ultrasonic nondestructive testing. He has published more than 560 academic papers which are indexed by SCI, including those published on “Nature Materials”, “Advanced Materials”, “Advanced Functional Materials”, “Nature Communications”, “Proceedings of National Academy of Sciences”, “Physical Review Letters”, “Prog. Material Science” and other top academic journals, as well as 5 co-authored academic monographs. According to Google’s statistics, his papers were cited more than 14,000 times, with an H - factor of 55. He has been granted 31 national invention patents, has hosted more than ten international conferences and delivered more than 200 conference invitation reports at various academic conferences. He has presided over more than 50 scientific research projects. Professor Cao is also one of the founders of the National Institutes of Health High Frequency Medical Ultrasonic Transducer Resource Center, and Chief Scientist of National 973 project. Professor Cao is currently a visiting professor at Harbin Medical University, a chair professor at Xiamen University’s Ocean Institute and a visiting chair professor at Shanghai Jiaotong University’s Mechanical and Electrical College. Universities and research institutes where he has served as visiting or part-time professors include: Los Alamos National Laboratory of the United States, Brigham Young University of the United States, City University of Hong Kong, Hong Kong Polytechnic University, Shonan Institute of Technology of Japan, Nanjing University, Suzhou University, Xiangtan University and Shanghai Silicate Institute of the Academy of Sciences.
Abstract of the presentation:
Since the Curie brothers discovered the Piezoelectric phenomena in quartz in 1880, piezoelectric materials have made great progress, and their applications have also penetrated into every corner of daily life, including medical ultrasonic transducers, sonar, stress sensors, automobile electronic injection, sound, alarm, piezoelectric motors, etc. Piezoelectric materials are the core of electromechanical devices and play a decisive role in the performance of electromechanical devices. Every development of piezoelectric materials will bring about a great improvement in the performance of piezoelectric devices. Barium titanate piezoelectric material was discovered in 1941 (Thurnaurer and Deaderick), its piezoelectric performance is ten times larger than that of quartz, while lead zirconate titanate-lead titanate solid solution piezoelectric ceramic (PZT) was born in 1955 (B Jaffe) and has dominated the piezoelectric material market, especially in the field of underwater acoustic transducers, due to its high voltage (3 - 5 times larger than barium titanate) and low manufacturing cost. The discovery of large-size relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) single crystal in 1997 has greatly improved the performance of many piezoelectric devices. Its piezoelectric performance can be as high as 5 times of that of PZT. The discovery of new materials has made breakthrough progress in medical ultrasonic diagnostic probes and vector hydrophones. In recent years, there have been many new developments in the research of piezoelectric materials, including textured PMN-PT ceramics, Sm - doped PMN - PT ceramics, lead-free piezoelectric ceramics and lead-free piezoelectric single crystals. The piezoelectric properties of the new SM-doped PMN-PT ceramics can be up to three times as high as PZT piezoelectric ceramics, while the properties of the new lead-free piezoelectric materials can reach or even exceed the level of PZT, which lays a material foundation for the development of environmental friendly lead-free electromechanical devices. This lecture will give a brief introduction to the new development of piezoelectric materials and give a preliminary explanation of the related physical mechanism of piezoelectric performance enhancement. The discovery of new materials has made breakthroughs in medical ultrasonic diagnostic probes and vector hydrophones. In recent years, there have been many new developments in the research of piezoelectric materials, including textured PMN-PT ceramics, Sm - doped PMN-PT ceramics, lead-free piezoelectric ceramics and lead-free piezoelectric single crystals. The piezoelectric properties of the new SM-doped PMN-PT ceramics can be up to three times as high as PZT piezoelectric ceramics, while the properties of the new lead-free piezoelectric materials can reach or even exceed the level of PZT, which lays a material foundation for the development of environmental friendly lead-free electromechanical devices. This lecture will give a brief introduction to the new development of piezoelectric materials and give a preliminary explanation of the related physical mechanism of piezoelectric performance enhancement.