Physics Colloquium: Single Flux Quantum Logic for Integrated Circuits, and Perovskites for Photovoltaics and Radiation Detectors
This is a past event.
Friday, September 30 at 1:00pm to 2:00pm
Dr. Deidra R. Hodges
ECE Department Chair, Associate Professor, Electrical and Computer Engineering
at Florida International University
High critical current Josephson Junctions (JJs) using superconductive Single Flux Quantum (SFQ) logic are being investigated for Integrated Circuits. Superconducting JJs having very fast switching speeds, and are considered for real time, high data rate, and highly serial signal processing enabling ultra-wide band, high sensitivity, low complexity sensors. At the device level, superconductive SFQ electronics technology provides fast low-energy switching. We have proposed design, simulations and test of digital integrated circuits based on superconductive SFQ logic for high Jc JJs, working with the Office of Naval Research (ONR), MIT LL and the Intelligence Advanced Research Projects Activity (IARPA).
The methylammonium lead iodide CH3NH3PbI3 (MAPbI3) perovskites have attracted a lot of attention as a possible absorber material for thin film solar cells due to their bandgap energy, high optical absorption coefficients and low-cost solution-processing deposition approaches. MAPbI3 perovskite solar cells have evolved with transformative potential with laboratory efficiencies greater than 20%. Perovskite absorber materials are very inexpensive to synthesize and simple to manufacture, making them an extremely commercially viable option. Perovskites of compositional variations ABX3 can yield a range of crystal structures, phases and stabilities. Here, we probe perovskites of compositional variations ABX3. We report on the structural and optical properties of these perovskites. Photovoltaic (PV) devices were fabricated using these high tolerance factor perovskites. We report we have achieved power conversion efficiencies (PCEs) greater than 21% using the high tolerance factor perovskites investigated. The high tolerance perovskites were also characterized using synchrotron X-ray absorption near edge structure (XANES) spectroscopy at the National Synchrotron Light Source (NSLS) II at Brookhaven National Laboratory (BNL).
Dr. Deidra R. Hodges is the Department Chair and Associate Professor in the Department of Electrical and Computer Engineering at Florida International University. Dr. Hodges is an exceptional leader in photovoltaics (PV) and solar energy research with extensive experience in PV and X- and gamma-ray radiation detectors for National Security. Dr. Hodges is highly focused in advancing Renewable Energy, Sustainability, Nuclear Materials and Extreme Photon Sensing. Her contributions include the support and development of the pixilated cadmium zinc telluride (CZT) gamma detector at BNL, and highly efficient thin-film mixed perovskite halides photovoltaics. She has achieved perovskite solar cell power conversion efficiencies greater than 21%, approaching the world record efficiency of 25.2%. Her network spans Department of Energy government laboratories including Brookhaven National Laboratory, Kansas City National Security Center Honeywell FM&T, and the National Renewable Energy Laboratory, collaborating with Scientists and as a user of facilities.