1. Condensed-Matter Physics & Materials Science Seminar

    "Printed nanocomposite capacitors for power conversion applications, and solution processed methods for producing ferroic complex oxide nanoparticles"

    Presented by Stephen O'Brien, Department of Chemistry, The City college of New York, New York, NY 10031, Energy Institute, City University of New York, NY 10031

    Monday, March 30, 2015, 11 am
    Conference Room, Building 480

    Hosted by: Yimei Zhu

    I will give an overview of the metacapacitors project, an ARPA-E sponsored project that aims to improve efficiency, functionality and form factor of off-line power converters suitable for LED solid-state lighting, with a view to developing an attractive technology platform for load management and power conversion across a broad range of applications. Based on integrated switched-capacitor (SC) topologies, the project adopts an integrated approach from materials to devices to circuits. We designed capacitors based on high-dielectric nanocrystals, that can be prepared using high throughput microfabrication/nanotechnology techniques, ink deposition and multilayering. The capacitor dielectric, a nanocomposite composed of (Ba,Sr)TiO3 nanocrystals in polyfurfuryl alcohol (BST/PFA, _ > 20 , 100Hz - 1 MHz , loss < 0:01 , 20 kHz ), targets a high volumetric capacitance density and ripple current capability. The capacitors were board-integrated with a custom hybrid-switched-capacitor resonant (HSCR) DC-DC converter, tested and demonstrated to operate with high efficiency. The methodology for preparing the capacitor dielectric films relies on a novel method to prepare complex oxides, followed by evaporatively driven self-assembly into thin films. I'll review rational synthetic design, multigram scaling, and dispersion formulation design, as well as recent advances in the synthesis and characterization of novel multiferroic and ferroelectric complex oxides. STEPHEN O'BRIEN is an Associate Professor of Chemistry at City College New York and a member of the CUNY Energy Institute. He holds appointments on the Doctoral Faculty of the CUNY Graduate Center and Grove School of Engineering. Steve is a researcher in nanomaterials synthesis, properties and structural characterization: nanoparticle synthesis and self-assembly into superlattices, transition metal oxide nanomaterials, high k dielectrics/memory materials. He is published in over