Mode: Mixed
Rigid and flexible optoelectronics devices (OEDs), e.g., solar cells (SCs), LEDs, and photodetectors (PDs) have been widely investigated for potential applications from solar farms to buildings, wearable electronics, and biomedical sensors. The poor heterogeneous interfaces between different layers of OED structures will cause irreversible degradation. In this talk, we will discuss new approaches to enhance the interfaces from electrodes to active layers to achieve high-performance foldable OEDs. While typical transparent electrodes, e.g., indium tin oxide (ITO), are costly and brittle, we developed a new class of foldable transparent electrodes through the unique triple atomic interfacial integrations of composite materials[1], showing superior device stability against mechanical-electrical-moisture operation with a folding radius of 0.75mm. We further improve device performance by several strategies, including sublattice structuring, adhesion enhancement, and strain relaxation of SCs[2-7], synergetic ligand designs of LEDs[8-10], and crystallization enhancement of PDs[11-12]. We demonstrated SCs with 25.8% efficiency and over 2000 hours operational stability[3], pure primary-color ultra-flexible LEDs with prolonged stability[8] and PDs with detectivity surplus III-V semiconductor ones[11].
Professor Wallace C. H. Choy is a full professor in the Department of EEE, HKU. His research interests cover organic/inorganic optoelectronic devices, flexible and transparent conducting nanostructures, metal oxides, and nanomaterial devices. He has published over 270 peer-reviewed papers, several book chapters, patents, and edited one book. He was recognized as the top 1% of most-cited scientists in Thomson Reuter’s Essential Science Indicators from 2014 to 2024.
He has served as a Member of Engineering panels of the Hong Kong Research Grant Council, an Assessor of the Enterprise Support Scheme Assessment Panel of the Innovation and Technology Commission of Hong Kong, a Specialist of the Hong Kong Council for Accreditation of Academic and Vocational Qualifications. He is an elected fellow of OSA/ Optica. He is an elected fellow of Optica.
Clean water and clean air are vital for public health. This project focuses on developing high-efficiency and environmentally sustainable filters for removing harmful air/water pollutants. The team has developed novel architectures and functionalities for the filters to achieve high permeance, high removal efficiency, and excellent reusability.
