Date: 22 October 2018 (Monday)

Time: 10:00 - 11:00 am

Venue: B6605, Yeung Kin Man Academic Building

Energy crisis is a broad and complex global topic. Natural resources such as gas and oil are limited in supply. Development towards renewable resources is one of the most important technologies in the world. Currently, photocatalytic and photoelectrochemical (PEC) water splitting devices under the irradiation of sunlight have received much attention for the production of renewable hydrogen from water. Solar energy conversion and storage through photoelectrolysis of water using semiconductors as both light absorber and energy converter to store solar energy in simple chemical bond, H2, become highly desirable approaches to solving the energy shortage challenge. We focus on the effort to develop an efficient Si-based PEC water splitting device. We introduce the surface textured Si heterojunction PEC cell consisting of ultrathin amorphous Si/crystalline Si as efficient and robust photoelectrodes. The solar to hydrogen conversion efficiency has been improved to 13.26%, which is the highest ever reported for Si-based photocathodes. Later on, we design the cascading energy band structure in Si via doping for facilitating carrier separation and novel electrode structures for 360^o light harvesting for hydrogen generation with ultrahigh current densities of 61.2 mAcm-2. The cells have been further demonstrated with excellent hydrogen production rate. In addition, our method can significantly improve the stability of Si-based solar cells in water to sustain up to 300 hr. These multifunctional designs provide the potential for the future development in the renewable energy market.

Biography

Dr. Jr-Hau He is an Associate Professor of Electrical Engineering at King Abdullah University of Science & Technology (KAUST). He got BS and PhD degrees at National Tsing Hua University in 1999 and 2005, respectively. He was a Visiting Scholar at Georgia Tech (2005), a Postdoc Fellow at National Tsing Hua University (2006) and Georgia Tech (2007), a Visiting Scholar/Professor at Georgia Tech (2008), UC Berkeley (2010 and 2014), and UC San Diego (2012-2013), HKPolyU (Dec. of 2014), and University Lille 1 (May of 2016) and Assistant/tenured Associate Professor at National Taiwan University (2007-2014). He has been a pioneer in optoelectronics, which reflects on his achievement of photon management on the light harvesting devices. He has conducted highly interdisciplinary researches to bridge those gaps between various research fields and between academia and industry. He has grants received: > US$ 10M since joining KAUST in July 2014 and garnered >10000 citations for a body of work consisted of >215 peer reviewed journal articles with 55 of H factor over his career and over 215 presentations in international conferences. His researches focus on 2D materials/electronics and photoelectrochemical water splitting and CO2 reduction. He participates actively in activities and services in scientific professional societies. He is a Fellow of OSA, RSC and SPIE, and a senior member of IEEE. 38 postgraduate students (12 Ph.D. and 27 M.S. students) under his supervision completed their degree studies. Visit his web for more information (http://nanoenergy.kaust.edu.sa).

Enquiry:

Department of Materials Science and Engineering

Email: mse@cityu.edu.hk

Tel: 3442 2985