DEPARTMENT OF APPLIED PHYSICS 116 Email jiyan.dai@polyu.edu.hk Qualification BSc (Fudan University) MSc (Tsinghua University) PhD (Chinese Academy of Sciences) ORCID ID 0000-0002-7720-8032 Prof. DAI Jiyan Professor Research Overview Prof. Dai's research interest covers mainly ferroelectric and piezoelectric materials and devices, high-entropy thermoelectric materials and thermoelectric thin films, high-entropy dielectric thin films for energy storage and piezo‐electrocatalytic materials. His group has been devoting to high-performance ultrasound transducers, including phase-array, annular-array, high-frequency transducers as well as endoscopic and intravascular ultrasound transducers for medical imaging. Prof. Dai has successfully finished two ITF projects in ultrasound transducers development and is running other ITF projects for high-frequency phase-array transducer for eye and small animal imaging. He has also led a National 973 project for high-performance ultrasound transducers, and has licensed his inventions to industry for production. These efforts and pioneer work have greatly accelerated the progress of China’s medical ultrasound imaging technology. Representative Publications • Monograph: Ferroic Materials for Smart Systems-from fundamentals to device application, Wiley (2020) • Phys. Rev. Lett. 122, 257601 (2019) • Energy Stor. Mater. 15, 91-97 (2018) • Sci. Adv. 4, 5096 (2018) • Nat. Commun. 8, 15217 (2017) • Energy Environ. Sci. 9, 454-460 (2016) Patents • US Patent, US 8536665B2 • China Patents 201110001124.8; 201110132195.1; 201010542689.2 Awards and Achievements • The 1st Class Award of Guangdong Province Natural Science, 2020 • President Award in Research Activity, The Hong Kong Polytechnic University, 2007 • Faculty Award in Research and Scholarly Activities, 2007 We experimentally demonstrate that a superparaelectric-like relaxor antiferroelectric behavior can be realized in the HfO2-based thin films and corresponding recoverable energy storage density over 100 J cm-3 can be achieved at efficiency higher than 80% as well as extremely high dielectric strength > 6 MV cm-1, compared to perovskite oxide materials. This is a record high energy storage density in all reported HfO2-based energy storage thin films, and beyond that, we also demonstrate their superfast charging/discharging as a capacitor.
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