Invite Speakers

Prof. Jui-Fen Chang

Speech Title: Engineering Vertical Charge Transport for Hybrid Organic–Inorganic Optoelectronics

Abstract: Vertical device architectures provide a distinctive route to controlling charge transport and reducing the lateral dimensions of electronic and optoelectronic devices. In this talk, I will discuss our development of hybrid organic–inorganic vertical transistors, with an emphasis on how materials interfaces, energy-level alignment, and device architecture collectively govern carrier injection and transport. By combining the electrical transport properties of inorganic semiconductors with the versatile optical and electronic characteristics of organic materials, we establish vertical transistor structures that operate at low voltages while simultaneously enabling high current densities, large current modulation, and compact device geometries. A central theme of this work is the spatial control of charge transport in vertically stacked heterostructures. Through experimental investigation and device-level modeling, we examine how interfacial energy barriers, carrier mobility, source configuration, and electrostatic interactions determine carrier injection and the formation of conducting pathways. These studies reveal that the performance of vertical transistors is governed not only by the intrinsic properties of individual semiconductor layers, but also by the spatial distribution of electrostatic potential and the manner in which carriers are injected and redirected across material interfaces. Such understanding provides a framework for rationally designing vertical devices with controlled current distribution and enhanced electrical performance. The same principles can be extended beyond conventional transistor operation to realize multifunctional optoelectronic devices. We demonstrate that appropriate control of materials interfaces and vertical charge-transport pathways enables light emission and photodetection within related device architectures. These results illustrate how materials selection, interface engineering, and vertical device design can be integrated to create compact and multifunctional optoelectronic platforms. The talk will conclude with perspectives on the opportunities and challenges of exploiting vertical charge transport for highly integrated electronics, displays, and emerging optoelectronic systems.

Biography: Dr. Chang received her Ph.D. in Physics from the University of Cambridge and has been a faculty member in the Department of Optics and Photonics at National Central University, Taiwan, since 2011. Her research focuses on organic optoelectronics, integrating semiconductor physics, materials science, device engineering, and optical design to uncover the fundamental mechanisms of organic semiconductor devices and develop next-generation electronic and photonic technologies. Her current research projects encompass high-performance vertical transistors, inorganic/organic hybrid devices, microcavity polariton systems, and advanced laser dyes for OLEDs and optically pumped lasers.

Dr. Rinlee Butch Cervera

University of the Philippines Diliman

Speech Title: Development of High-Performance Regenerated Cathodes from Waste EV Lithium-Ion Batteries for All-Solid-State Lithium-Ion Batteries

Abstract: The rapid global adoption of electric vehicles has made end-of-life lithium-ion batteries both an urgent environmental challenge and a strategic materials opportunity. This study investigated cathode regeneration from spent EV lithium-ion batteries as a sustainable route for producing functional cathode materials for next-generation all-solid-state lithium-ion batteries (ASSLBs). Waste battery materials were systematically recovered, separated, purified, and reconditioned through targeted regeneration and relithiation processes to restore their structural integrity and electrochemical functionality. Using this approach, both LiFePO₄ (LFP) and Nickel-rich manganese oxide (NMC) cathodes were successfully regenerated from waste EV battery black mass. X-ray diffraction (XRD) confirmed retention of the orthorhombic olivine LFP structure. For NMC precursor recovery, X-ray fluorescence (XRF) analysis indicated an Ni:Mn:Co atomic ratio of approximately 76:10:14. The regenerated materials exhibited good crystallinity, and complementary characterization by SEM/EDS, FTIR, and Raman spectroscopy confirmed promising recovery of morphological, structural, and compositional properties. Hydrothermal relithiation successfully restored the olivine structure of regenerated LFP and improved the crystallinity and layered cation ordering of regenerated NMC, with EDS mapping revealing significantly reduced Mn segregation relative to the pristine waste black mass. When incorporated into all-solid-state cell configurations, the regenerated cathodes delivered promising electrochemical performance. Collectively, these results establish a viable circular materials pathway in which spent EV batteries are transformed into high-value cathode materials for safer and more sustainable next-generation energy storage systems.

Biography: Dr. Rinlee Butch Cervera is a Full Professor at the Department of Mining, Metallurgical, and Materials Engineering, University of the Philippines Diliman, where he also heads the Energy Storage & Conversion Ma-terials Research Laboratory. He currently serves as Program Coordinator of the Energy Engineering Graduate Program at UP Diliman. A distinguished researcher, innovator, and academic leader in materials and energy engineering, Dr. Cervera has led numerous research and development initiatives in renewable and alternative clean energy. His work focuses on energy storage systems, including fuel cells, hydrogen energy, lithium-based batteries, battery recycling and mining, valuable metals recovery, and waste-to-energy conversion. He is also actively engaged in techno-economic feasibility studies, multi-criteria decision analysis, and technology assess-ment in energy-related fields. Dr. Cervera obtained his BS in Materials Engineering from UP Diliman, his MS from Universiti Sains Malaysia, and his PhD from the University of Tokyo. He also completed postdoctoral fel-lowships at the University of Tokyo and the National Institute for Materials Science (NIMS), Japan. Recognized for his technical expertise and scientific leadership, Dr. Cervera has received several prestigious honors, includ-ing the DOST Balik Scientist Award, the Outstanding Young Scientist Award from the National Academy of Science and Technology (NAST), the TWAS Young Affiliate Award, the David M. Consunji Award for Engineer-ing Research, and recognition as one of the Top 100 Asian Scientists in 2023. He actively serves on the tech-nical committees of various international and national conferences and workshops and is a member of several technical working groups that help shape research agendas, policy recommendations, and standards in energy, materials, and sustainability. He is also a member of leading professional organizations, including the Philippine-American Academy of Science and Engineering (PAASE), the Philippine Association for the Advancement of Science and Technology (PhilAAST), the Solid State Ionics Society, The Electrochemical Society (ECS), and the Energy Research Institutes Network (ERIN). He is the founding president of the Institute of Materials Engi-neers of the Philippines (IMEP) and currently serves as Editor-in-Chief of the Philippine Engineering Journal (PEJ).