Summer Seminar Series 2021

New Light: Rising Stars in Energy and the Environment is a summer seminar series, held between June 17 and July 28, to spotlight associate research scholars, postdoctoral research fellows, and other early-career researchers affiliated with the Andlinger Center for Energy and the Environment. Weekly seminars will feature a diverse selection of researchers working on cutting-edge topics across disciplines seeking to solve society’s most pressing problems in energy and the environment. The video recordings of the seminars can be found below.

Azarakhsh Jalalvand

Data scientist, visiting postdoctoral research associate at Plasma Control Group, Princeton University

Real-Time Remote Sensing and Fusion Plasma Control: A Reservoir Computing Approach

June 17 at 11 a.m.

Jalalvand is a senior data scientist at Ghent University-imec, in Belgium, and a visiting postdoc at Plasma Control Group at Princeton University since 2020. Jalalvand obtained his doctoral degree in 2015 in Artificial Intelligence and continued his career as a permanent postdoctoral researcher at IDLab-UGent-imec. Jalalvand has contributed to over 20 (inter-)national projects, leveraging fundamental and applied research in diverse data analysis directions such as pathological speech/image processing, radar signal processing, bioinformatics, anomaly detection, and predictive maintenance. In 2020, he was awarded a 3-year special postdoctoral fellowship at UGent-BOF to investigate data-driven models for condition monitoring and plasma control in the magnetic confinement devices to produce controlled thermonuclear fusion power.

Read Azarakhsh's abstract

Nuclear fusion power is a potential source of safe, non-carbon emitting and virtually limitless energy. The tokamak is a promising approach to fusion based on magnetic plasma confinement, constituting a complex physical system with many control challenges. However, plasma instabilities pose an existential threat to a reactor which has not yet been solved. Since current physical understanding is not sufficiently advanced to reliably predict instabilities, a way forward is Artificial Intelligence and data-driven models. In this presentation, we discuss the application of such models in predicting the plasma profiles on confinement time scales using experimental data from DIII-D tokamak. The conducted experiments demonstrate that simple yet effective machine learning models, namely Reservoir Computing Networks (RCN), achieve comparable results to state-of-the-art deep convolutional neural networks and long short-term memory (LSTM) models, with significantly easier and faster training procedure. This superiority allows for fast and frequent adaptation of the model to new situations, such as changing the environment conditions or predicting plasma profiles on a different fusion device.
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Lianfeng Zhao

Postdoctoral research associate, Department of Electrical and Computer Engineering, Princeton University

Metal Halide Perovskites: Towards Practical Photovoltaics and CMOS-compatible Light Emitters

June 24 at 11 a.m.

Lianfeng Zhao is currently a postdoctoral research associate in the Department of Electrical Engineering at Princeton University. He received a B.S. from Xidian University in 2012, M.S. from Tsinghua University in 2014, and Ph.D. from Princeton University in 2019. His research interests are in optoelectronic thin-film devices, systems, and applications. He was the recipient of the 2018-2019 Princeton Wallace Memorial Fellowship in Engineering, 2017 Princeton SEAS Award for Excellence, 2014 Tsinghua Best Thesis Award and Tsinghua Outstanding Graduate for Academic Achievement Award.

Read Lianfeng's abstract

Metal halide perovskite semiconductors, a class of hybrid organic-inorganic semiconductors, hold the potential to become the backbone of a new generation of photovoltaic solar cells and light emitting diodes (LEDs). The power conversion efficiencies of metal halide perovskite solar cells currently exceed 25% (best in class for thin-film solar cells), and the external quantum efficiencies for metal halide perovskite LEDs have reached approximately 20%.

Despite rapid laboratory advances in device performance, a better understanding of their fundamental properties is crucial for optimization and commercialization. In this seminar I will describe research in our group on fundamental properties of metal halide perovskite semiconductors, and how that understanding can be deployed to immediately benefit device performance and stability. Our findings on intrinsic chemical properties of metal halide perovskites reveal fundamental principles for pursuing stable solar absorbers and light emitters and suggest strategies to achieve stable bandgap tunability for wavelength-tunable LEDs, lasers and tandem solar cells. Finally, mechanical stability has been improved by pursuing molecular engineering for flexible applications, and thermal management strategies have been explored for high-power applications.
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Erin Mayfield

Associate postdoctoral researcher, The High Meadows Environmental Institute, the Andlinger Center for Energy and the Environment, Princeton University

Designing Net-Zero Emissions Energy Systems to Address Environmental and Societal Objectives

June 30 at 11 a.m.

Erin Mayfield is a sustainable systems engineering and public policy researcher. Currently an associate research scholar at Princeton University, she will be an assistant professor at Dartmouth College beginning in September. Her research focuses on developing multi-objective computational models that integrate technoeconomic, environmental, and social equity objectives to inform energy and industrial infrastructure system transitions in the context of climate change. She previously worked as an environmental engineer on natural resource damages litigation related to the Deepwater Horizon oil spill, hazardous waste remediation, and ecosystem services valuation related to petrochemical and pesticide contamination. Mayfield has also held positions at the U.S. Environmental Protection Agency, U.S. Congress, and Environmental Law Institute. She received her bachelor’s degree in environmental science from Rutgers University, master’s degree in environmental engineering from Johns Hopkins University, and Ph.D. in engineering and public policy from Carnegie Mellon University.

This seminar is co-sponsored by The High Meadows Environmental Institute.

Read Erin's abstract

Achieving economy-wide net-zero emissions will entail transformational changes in engineered systems across sectors. As part of this, future energy and industrial infrastructure systems will need to be designed to balance the often-conflicting objectives of multiple actors.

Macro-energy system models are increasingly used to plan systems and typically adopt least-cost objectives to select optimal technoeconomic pathways to achieve climate goals. In contrast, non-cost objectives, related to pollution or jobs, for example, that may influence decision and design processes are often treated as outcomes rather than explicit objectives.

This presentation will review potential technological scenarios for infrastructure deployment to achieve net-zero emissions by mid-century. An approach for operationalizing non-cost objectives associated with air quality, labor, and land use in macro-energy system models will be presented. This approach will be demonstrated through case studies of coal electric power retirements, natural gas supply chain development, and utility-scale solar siting.
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Yenan Chen

Postdoctoral research associate, Department of Electrical and Computer Engineering, Princeton University

Power Electronics for Efficient Energy Delivery Systems: Architecture and Topology

July 8 at 11 a.m.

Yenan Chen received his bachelor’s degree and Ph.D. degree from Zhejiang University, Hangzhou, China, in 2010 and 2018 respectively, both in Electrical Engineering. Since 2018, he has been a Postdoctoral Research Associate with the Department of Electrical Engineering, Princeton University. His research interests include high frequency power converters, advanced power electronics architecture, grid-interface power electronics and renewable energy systems. He holds three issued Chinese patents. Chen received the APEC Outstanding Presentation Award in 2019, the First Place Award from the Innovation Forum of Princeton University in 2019, the Best Paper Award in COMPEL 2020, and the the Postdoc Researcher Presentation Award at the 2020 Princeton Andlinger Center Annual Meeting.

Read Yenan's abstract

Power electronics convert and control electric power in various systems, including household electronics, renewable energy generation and distribution, data centers, and electric vehicles (EVs). This presentation will introduce Princeton PowerLab’s research on advanced power electronics architecture and topology for improved performance and efficiency, with special attention to the multi-input multi-output (MIMO) energy router and ultra-high-current CPU voltage regulator.

With the increasing adoption of distributed energy resources, EVs, and energy storage, MIMO power conversion is needed for grid edge applications. Connecting many sources or loads together with a MIMO energy router can reduce the power conversion stress, improve the efficiency, and enhance the power density. Challenges of MIMO power conversion will be discussed and recent advances will be presented.

Modern high-performance microprocessors (e.g., CPUs, GPUs, TPUs) switch at GHz frequencies and consume hundreds of amperes of current at very low voltage (i.e., <=1 V). It is a fundamental challenge to support such large currents while maintaining high energy efficiency. The second part of this talk will introduce the ultra-high-current CPU voltage regulator, a new architecture designed to address this challenge.
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Sunxiang Zheng

Distinguished Postdoctoral Fellow, Andlinger Center for Energy and the Environment, Princeton University

Harvesting Natural Energy for Water Vaporization: A New Route Towards Sustainable Desalination

July 15 at 11 a.m.

Sean Zheng is currently a Distinguished Postdoctoral Fellow at the Andlinger Center for Energy and the Environment. His research focuses on developing novel nanomaterials and technologies for energy-efficient carbon capture and mineralization, collaborating with Profs. Z. Jason Ren and Claire White. Zheng received his PhD in Environmental Engineering in 2020 from University of California, his B.S. from Zhejiang University of Technology (China) in 2013, and his M.S. degree in 2015 from University of Maryland, College Park.

Read Sunxiang's abstract

As available fresh water resources continue to decline, alternative water sources will become a critical component of sustainable water systems. Centralized desalination facilities using thermal or membrane-based technologies have emerged as an important strategy to mitigate water stress worldwide, but high energy demand and complex infrastructure limit their implementation in rural areas and underdeveloped regions.

Natural evapotranspiration is the largest desalination mechanism in the global water cycle. Inspired by this, we have developed new desalination methods powered by natural energy (e.g. solar, wind). This talk will provide an overview of this emerging technique and introduce a continuous desalination process using natural wood-derived materials. Taking advantage of the water lifting capability of wood xylems, we designed a tall “engineered tree” that draws from multiple environmental energy sources including solar, wind, or ambient heat in the air to produce fresh water at a rate of 4.8 to 14 liters m^-2 h^-1. Although drought-stricken regions without safe or stable water sources are prime candidates for this device, its use of ambient energy sources could make it attractive to small communities or commercial buildings in developed areas, and it would also be beneficial for off-grid homes and emergency preparedness.

Sara Constantino

Associate Research Scholar, Center for Policy Research on Energy and the Environment, School of Public and International Affairs, Princeton University

Social Accelerants and Decelerants of Climate Action

July 22 at 11 a.m.

Sara Constantino is an interdisciplinary social scientist working on social and environmental policy and decision-making. She is currently an associate research scholar at the School of Public and International Affairs at Princeton University and a Lecturer at the High Meadows Environmental Institute, and will be starting as an assistant professor at Northeastern University in January. Her research focuses on understanding the interplay between individual, institutional and ecological factors on perceptions, policy preferences and responses or resilience to extreme events. In particular, recent studies look at the role of polarization, social norms and governance in stimulating or stifling support for climate action. Previously, she was a senior research fellow with the Jain Family Institute, an applied research organization that focuses on welfare policy and digital ethics, and a founding editor at Nature Human Behavior. She received her bachelor’s degree in economics from McGill University, a master’s degree in economics from University College London, and a Ph.D. in cognitive sciences, with a focus on learning and decision-making in dynamic environments, from New York University.

This talk is co-sponsored by the Center for Policy Research on Energy and the Environment and the Arthur L. Irving Institute for Energy and Society at Dartmouth.

Read Sara's abstract

The scale and pace of carbon-intensive development has driven climate change and biodiversity loss, with unequal social impacts. However, despite the transformative change needed across our social and economic systems to address these issues, and the technological ability to do so on many fronts, there is continued political resistance to passing new legislation or changing the status quo. Against this backdrop, recent opinion pieces have highlighted the potential for local shifts in social norms and values to trigger widespread social change and collective climate action from the “bottom-up”. Critically, the success of these movements depends on how climate change maps onto group identities, such as political affiliation.

In this presentation, I will focus on some recent and ongoing studies that use repeated surveys, virtual lab experiments, and pre-existing datasets to shed light on the role of social factors and experience of extreme events in shaping perceptions and values, policy preferences and coordinated action. In particular, I will present results from a study showing how polarization or strong in and out-group identities can facilitate coordination on existing norms but also stifle the emergence of new collectively beneficial norms. This work suggests that social norm interventions aimed at increasing sustainable behaviors or values will need to grapple with existing partisan or group divisions. I will then show results of an ongoing study that shows how experience of extreme events such as Covid-19 or extreme weather can start to close the partisan gap on risk perceptions, trust in social institutions and policy preferences.
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Melissa Ball

Presidential Postdoctoral Fellow, Andlinger Center for Energy and the Environment, Princeton University

Molecular Design for Emerging Solar Materials

July 28 at 11 a.m.

Melissa Ball received her doctorate in chemistry from Columbia University under Professor Colin Nuckolls. Her thesis focused on structure-function relationships between molecular design of organic small molecules and organic electronics. At her time at Columbia, she co-authored over ten publications and was awarded the Presidential Award for Outstanding Teaching for her efforts in the classroom. Melissa joined the Loo Group at Princeton University as a Presidential Postdoctoral Fellow in 2019. Her work in the Loo Group centers on the design of UV absorbers for transparent photovoltaic devices. These devices can be used as the power source for smart windows or for applications where color neutrality is a primary objective.

This talk is co-sponsored by the Arthur L. Irving Institute for Energy and Society at Dartmouth.

Read Melissa's abstract

Solar technologies will play an important role in helping us meet our goal of net-zero carbon emissions by 2050. While silicon is the workhorse of the solar energy field, technologies built on emerging materials can both supplement silicon, as deployment demands will be great in the coming decades, and also address energy markets not accessible to silicon. This talk will cover two areas of research that demonstrate the potential for novel solar technologies to provide solutions for our energy and environmental future. First, I will show how manipulating the organic cation in two-dimensional perovskites allows control of structural properties that, in turn, affect materials properties and produce high efficiency solar devices. Second, I will discuss our work on design and synthesis of donor absorber materials that serve as the basis for transparent photovoltaics. The resulting solar cells are the most color neutral and transparent photovoltaics to-date.
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The 2020/2021 Highlight Seminars Series

Princeton University

New Light: Rising Stars in Energy and the Environment