PVSC PROGRAM

Tutorial AM2: Advanced Concepts: Fundamentals on Advanced Conversion Concepts & Photonics

Instructors:
JF Guillemoles, CNRS/E. Polytechnique, France
Jeronimo Buencuerpo, CNRS, France

Tutorial Description
Photovoltaics had made impressive progress in the past decades and is likely to do so in the next as performances are still far from the known limits, either in terms of efficiency of conversion or in efficiency of material usage. This tutorial will present what ultimate performances in photovoltaic conversion are and current investigations on how they could be approached. Those attending this tutorial should leave with
(i) an overview of the possibilities to increase photovoltaic performance,
(ii) tools for assessing the potential of new concepts,
(iii) state of the art and perspectives for a practical development.

The first part will present detailed balance models, as a base to describe advanced concepts of PV conversion in a very general, yet effective, framework. This formalism will enable to describe various approaches to very high efficiencies of conversion in a consistent way and discuss the relative merits of various approaches. The tutorial will start with the description of the single band gap solar cell model and build from there models for more exotic conversion devices (Intermediate band, Hot carrier, Multiple exciton generation, up/down conversion, thermophotovoltaics, rectennas, etc.), with the multijunction device as a reference.

A severe practical limit to many of the concepts presented starts with the photon absorption efficiency. This also defines how much active material needs to be used for an efficient conversion. Photonics revolution has significantly opened possibilities to increase materials effectiveness in the conversion processes by several orders of magnitude. Limits and possibilities of photon management will be introduced, and most recent findings will be presented in accessible terms.

At this point, it will be useful to compare theoretical expectations with practical realizations. Many concepts have been tested, and albeit demonstrated performances are still far from the ultimate limits, some notable successes have been recorded in various directions. The third session will present an overview of the experimental state of the art and will give an opportunity to discuss specific challenges in the various pathways to ultimate efficiencies that have to be met.

Finally, methods to simulate /model advanced concepts go beyond the tools used for current devices. They are essential to guide the research where experiments are difficult. An overview of the tools will be presented.

J-F Guillemoles is a CNRS Research Director, head of the IPVF joint lab (CNRS- E. Polytechnique- ENSCP-and SAS IPVF), Paris-Saclay (France) aiming at the development of photovoltaics, and former director of a joint lab with the University of Tokyo, NextPV. Scientifically active on high efficiency concepts for solar energy conversion, new applications for photovoltaic, luminescence-based characterization techniques (esp. Hyperspectral imaging), and modeling of photovoltaic materials and devices. He is part time Professor at Ecole Polytechnique, author/co-author of more than 450 publications (peer-reviewed papers, book chapters, patents, proceedings …), editor for Progress in Photovoltaics (Wiley) and EPJPV (EDP), and director of several large R&D programs, such as PEPR TASE.

Jeronimo Buencuerpo did his Ph.D. at the Institute of Micro- and Nanotechnology of Madrid (IMN-CSIC) (Spain), developing nanostructured antireflection coatings for III-V multijunction solar cells using laser interference lithography. He worked in NREL (Colorado, US) as a postdoc from 2018-2021, working on quasi-random photonic crystals for weak absorbing structures as quantum wells and ultrathin GaAs solar cells, and in the development of three terminal tandems solar cells. Lately, he joined L’Institut Photovoltaïque d’Île-de-France (IPVF), (France) in October 2021 to develop tandem ultrathin III-V solar cells on Si in collaboration with the SunLit Team from the Center for Nanoscience and Nanotechnology (C2N, France).

He has taught Optics at the Faculty of Physics at the University Complutense of Madrid, and Photovoltaics at the École Nationale Supérieure de Techniques Avancées (ENSTA) Paris. He is associate editor in the Journal of Photonics for Energy (SPIE).

He works primarily on III-V ultrathin and tandem solar cells for terrestrial and space applications. His research interests are photonics applied for solar, nano-processing, and computational physics.

Tutorial AM3: Silicon Photovoltaic Technology

Instructor:
Anastasia H. Soeriyadi, University of Oxford, UK

Description
This tutorial will begin with a brief introduction to what is needed to make a solar cell out of a semiconductor, thereby briefly explaining the basics of photovoltaics. We will then show different strategies to make a good solar cell, introducing surface passivation, light trapping, local contacts and local doping and metallization strategies while always using typical Si solar cell structures as examples. For each part, we will discuss the ideal case and the industrial case which can be limited due to cost, throughput and material scarcity. From this, we will go on looking into making really good Si solar cells by using passivating contacts and interdigitated back contact (IBC) schemes which are the current industrial standards and the next state-of-art technology. we will look a bit closer at Si solar cells currently in production and the latest trends in the industry from cell variation and lamination strategies. This will then be topped by analyzing the potential of multi-junction cells on Si while focusing on the integration of Si as the bottom cell for various top cell technologies.

Anastasia H. Soeriyadi is currently a postdoctoral research scientist in the Electronic and Interface Materials Laboratory under the Department of Materials, at the University of Oxford focusing on the development of a bifacial passivation layer for PERC and TOPCON solar cells and the interface layer between perovskite and silicon solar cells in a monolithic tandem structure.

Dr. Soeriyadi completed her PhD in Photovoltaics in 2018 focusing on device design and circuit analysis of a GaAsP/SiGe on Si substrate tandem solar cell. She then furthers her fabrication skills in full-size silicon solar cells during her postdoctoral research associate time at UNSW from 2018-2021. Her project focused on the development of p-type silicon heterojunction cells. She has collaborated with various research institutes and industries globally working on different Silicon cell structures including polysilicon, heterojunction, and black silicon solar cells. In 2022, she was awarded the Australian Centre for Advanced Photovoltaics (ACAP) fellowship to further develop III-V/Si devices (current world record for 2J monolithic). During this post, she led a III-V fabrication team at SPREE, UNSW, working on various design structures of III-V multijunction solar cells, including for concentrator applications.

Tutorial AM4: Performance Testing of PV Cells and Modules

Instructors:
Tao Song, National Renewable Energy Laboratory, USA
Nikos Kopidakis, National Renewable Energy Laboratory, USA

Tutorial Description

• 1. Fundamentals
a. Definitions: irradiance (total, spectral), Standard Test Conditions (STC)
b. PV testing basics – Spectral response, current-voltage (I-V) characteristics
c. Translation of indoor test to STC – spectral mismatch, temperature corrections
d. The PV calibration chain, traceability, and the meaning of “ISO accreditation”
e. Measurements outside STC
f. Performance testing of PV modules g. International Standards
• 2. Multijunction PV cells
a. Spectral response measurements
b. Spectral matching and simulator considerations for performance testing of 2T cells
• 3. Emerging PV cells including tandems
a. Special considerations for performance testing single-junction perovskite and other emerging PV cells: spectral response and maximum power determination for single-junctions
b. Performance testing multijunction emerging PV cells: special conditions, sources of error and common measurement pitfalls
• 4. Emerging PV modules
a. Current status of perovskite and other emerging PV module performance measurements

Tao Song is a research scientist in the PV Cell and Module Performance Group at NREL and has led the cell performance calibration since 2018. He received his Ph.D. in physics from Colorado State University in 2016, with a research focus on device characterization and simulation of thin-film CdTe and CIGS solar cells. Then, he joined NREL as a post-doc for 1.5 years before promoting as a staff scientist. His research interest covers the high-precision efficiency calibration of any kinds of solar cells and the development of reliable measurement techniques for novel and emerging PV devices.

Nikos Kopidakis is a research scientist at NREL and the technical lead of the PV Cell and Module performance group. He has over 20 years of experience in PV research, including silicon, dye-sensitized and organic PV. His interests cover the performance characterization of PV cells and modules of any size and technology and new measurement techniques for novel and emerging PV. He has previously worked on new materials for PV applications and in spectroscopic techniques for characterizing their photophysics.

Tutorial AM5: Tandems and Multijunction Photovoltaics

Instructor:
Myles Steiner, National Renewable Energy Laboratory, USA
Emily Warren, National Renewable Energy Laboratory, USA

Description
This tutorial will give a general introduction to the field of tandem solar cells for the use in terrestrial and space systems. It will start from basic theoretical considerations and explain the benefits of using several pn-junctions to convert the broad solar spectrum into electricity. Since III-Vs have historically dominated the field of multijunctions and high efficiency photovoltaics, we will review III-V multijunctions as a model system for other tandems. Some of the specific requirements for the use of multijunctions in different environments will be introduced, such as high current capacity for concentrators, radiation hardness for space applications, and low cost for one-sun applications.

New and on-going efforts toward hybrid tandems, combining cells of different material systems, will then be covered in detail. Silicon- and perovskite-based tandem devices offer the promise of similarly high conversion efficiencies as traditional tandem III-Vs, but at a fraction of the cost. However, these integrated materials systems also come with unique issues that arise due to the various dissimilarities between the materials and the fabrication processes required for different technologies. We will look at the advantages and disadvantages of different material and interconnection combinations (e.g. 2T, 3T, 4T) in terms of efficiency, cost, and scalability.

Myles Steiner is a senior scientist at the National Renewable Energy Laboratory, in Golden, Colorado, where he leads NREL’s III-V Photovoltaics Core program. His work focuses on the development of III-V multijunction solar cells for terrestrial and space power generation, thermophotovoltaics for energy storage, and solar fuels by photoelectrochemical generation.

<Emily Warren is a Group Manager at the National Renewable Energy Laboratory, in Golden, Colorado, where she leads the High Efficiency Tandems, Cell & Module Performance Group as well as the Tandem Photovoltaics Core program. Her research interests focus on the fabrication and modeling of multi-terminal tandem solar cells and modules. She also studies novel architectures for the creation of solar fuels and dabbles in heteroepitaxial growth of III-V materials on silicon nanoimprint lithography.

Tutorial PM1: Sustainability and Circular Economy for PV

Instructor:
Annick Anctil, Michigan State University, USA
Preeti Nain, Michigan State University, USA

Tutorial Description
Photovoltaics is expected to become the dominant pillar of global energy production with the global energy system transition to 100% renewable energy. As PV scales up globally, questions arise about the availability of resources, the cost and environmental impact of PV production, the toxicity of the modules and materials used, the impact on land and ecosystem during and after system installation, and finally, modules recyclability at end-of-life.

After an introduction about the PV supply chain and market, this tutorial will give an overview on methodologies for the economic, ecologic, social assessment of photovoltaics. This tutorial will introduce sustainability concepts and methodologies such as life cycle assessment, techno-economic analysis, environmental toxicity, risk assessment, and circular economy for solar PV.

We will discuss sustainability concerns for each of the life cycle stages of a PV module. An overview of critical and non-critical material demand and the role of recycling in ensuring future supply will be presented. Concerns at the end-of-life related to material leaching potential and consequent human health risk for unsafe disposal scenarios will be covered. Finally, we will summarize applicability of standard waste characterization methods, regulations, and end-of-life management requirements in various regions.

A summary of the policy and restrictions in the US and Europe and their impact on manufacturing, end-of-life PV waste management and recycling will also be discussed, including the environmental and cost impact of manufacturing in various locations.

  Annick Anctil is an associate professor in Civil and Environmental Engineering at Michigan State University, where she leads research on Sustainable Energy Systems. She holds a BE and MS in Materials Engineering and a Ph.D. in Sustainability. The core of her research is evaluating the environmental impact of photovoltaics technologies. She participated in the NSF International Standard on Sustainability Leadership for Photovoltaics Module and the EPEAT Ultra-low carbon solar modules criteria. She is the assistant director of the Michigan DOE Industrial Assessment Center and received an NSF CAREER award in 2021 to work on the impact of the solar photovoltaics industry in the US. She was selected as a Michigan Clean Energy Leader in 2018 and is currently on the board of directors of the Michigan Institute for Energy Innovation (IEI).

Preeti Nain is a postdoctoral researcher in Civil and Environmental Engineering at Michigan State University, United States. She received her Ph.D. in Environmental Engineering from Indian Institute of Technology, Delhi, India. Her research investigates different aspects of end-of-life solar photovoltaics. Her current interests include PFAS analysis in solar photovoltaics and life cycle assessment for PV repowering in the United States.

Tutorial PM2: Advanced Concepts: Experimental Progress with New Concepts in PV and Device Simulations

Instructor:
Yoshitaka Okada, University of Tokyo, Japan
Stephen M. Goodnick, Arizona State University, USA

Tutorial Description
Photovoltaics had made impressive progress in the past decades and is likely to do so in the next as performances are still far from the known limits, either in terms of efficiency of conversion or in efficiency of material usage. This tutorial will present what ultimate performances in photovoltaic conversion are and current investigations on how they could be approached. Those attending this tutorial should leave with
(i) an overview of the possibilities to increase photovoltaic performance,
(ii) tools for assessing the potential of new concepts,
(iii) state of the art and perspectives for a practical development.

The first part will present detailed balance models, as a base to describe advanced concepts of PV conversion in a very general, yet effective, framework. This formalism will enable to describe various approaches to very high efficiencies of conversion in a consistent way and discuss the relative merits of various approaches. The tutorial will start with the description of the single band gap solar cell model and build from there models for more exotic conversion devices (Intermediate band, Hot carrier, Multiple exciton generation, up/down conversion, thermophotovoltaics, rectennas, etc.), with the multijunction device as a reference.

A severe practical limit to many of the concepts presented starts with the photon absorption efficiency. This also defines how much active material needs to be used for an efficient conversion. Photonics revolution has significantly opened possibilities to increase materials effectiveness in the conversion processes by several orders of magnitude. Limits and possibilities of photon management will be introduced, and most recent findings will be presented in accessible terms.

At this point, it will be useful to compare theoretical expectations with practical realizations. Many concepts have been tested, and albeit demonstrated performances are still far from the ultimate limits, some notable successes have been recorded in various directions. The third session will present an overview of the experimental state of the art and will give an opportunity to discuss specific challenges in the various pathways to ultimate efficiencies that have to be met.

Finally, methods to simulate /model advanced concepts go beyond the tools used for current devices. They are essential to guide the research where experiments are difficult. An overview of the tools will be presented.

Yoshitaka Okada is a Professor at the Research Center for Advanced Science and Technology (RCAST), the University of Tokyo. He received his BSc degree in Electronic and Electrical Engineering from King’s College, the University of London in 1984, and PhD in Electronic Engineering from the University of Tokyo in 1990. He was appointed as a Visiting Assistant Professor in the Department of Electrical Engineering, Stanford University in 1995-96, Visiting Fellow in the Department of Physics, Imperial College London in 2006, and Visiting Fellow of the Cavendish Laboratory, University of Cambridge in 2015. His recent research interests include thin-film growth of low-dimensional InAs/GaAs-based III-V quantum nanostructures for applications to advanced high-efficiency photovoltaics such as intermediate-band and hot carrier solar cells. He has been the co-author of over 220 journal papers and over 190 international conference presentations. He is a Fellow of the Japan Society of Applied Physics (2020) for contribution to innovative high-efficiency quantum nanostructure solar cells and materials. He is also a Senior Member of IEEE and served as a Co-Chair at the PVSC Conference in 2010 and 2012, and as an Area Chair at the 6th WCPEC in 2014.

Stephen M. Goodnick is the David and Darleen Ferry Professor of Electrical Engineering at Arizona State University. He received his Ph.D. degrees in electrical engineering from Colorado State University, Fort Collins, in 1983, respectively. He was an Alexander von Humboldt Fellow with the Technical University of Munich, Munich, Germany, and the University of Modena, Modena, Italy, in 1985 and 1986, respectively. He served as Chair and Professor of Electrical Engineering with Arizona State University, Tempe, from 1996 to 2005. He served as Associate Vice President for Research for Arizona State University from 2006-2008, and presently serves as Deputy Director of ASU Lightworks as well as the DOE ULTRA Energy Frontier Research Center. He is also a Hans Fischer Senior Fellow with the Institute for Advanced Studies at the Technical University of Munich. Professionally, he served as President (2012-2013) of the IEEE Nanotechnology Council and served as President of IEEE Eta Kappa Nu Electrical and Computer Engineering Honor Society Board of Governors, 2011-2012. Some of his main research contributions include analysis of surface roughness at the Si/SiO2 interface, Monte Carlo simulation of ultrafast carrier relaxation in quantum confined systems, global modeling of high frequency and energy conversion devices, full-band simulation of semiconductor devices, transport in nanostructures, and fabrication and characterization of nanoscale semiconductor devices. He has published over 450 journal articles, books, book chapters, and conference proceeding, and is a Fellow of IEEE (2004) and AAAS (2022) for contributions to carrier transport fundamentals and semiconductor devices.

Tutorial PM3: Emerging Space Photovoltaics: Unique Semiconductors, Device Designs, and Radiation Interactions

Instructor:
Louise C. Hirst, University of Cambridge, UK
Ahmad R. Kirmani, Rochester Institute of Technology, USA

Description
Space applications have long been a driving force for innovation in photovoltaic materials and devices, since the launch of the first solar power satellite, Vanguard I, in 1958. Space power systems have a unique set of requirements including high specific power and tolerance to radiation exposure, necessitating space specific solutions. In recent years the space sector has seen rapid evolution with commercialization of the sector and increasingly widespread use of space-based services including global communication networks and the future prospect of space based solar power, as well as ambitious targets for space exploration and discovery science in space. The photovoltaic power system is critical to enabling these exciting new possibilities. This tutorial will cover space applications and environments relevant to the new space era, as well as current and emerging technologies. Ultrathin III-V solar cell architectures and metal-halide perovskite semiconductors are being pursued with intense vigor for space power applications owing to their unique radiation tolerance properties and will form a major focus of this tutorial. It will be delivered in two parts.

• Part 1: Space PV requirements and challenges of this environment
• Design of current commercial space PV systems
• Radiation damage mechanisms in conventional space PV materials
• Practical tools for simulating radiation environments, mission profiles and corresponding solar cell damage
• Evolution of the space sector driving design innovation




• Part 2: Metal-halide perovskite space solar cells
a. Unique radiation-matter interactions in perovskite semiconductors
b. Soft lattice nature and healing phenomena in perovskite semiconductors
c. Perovskite solar cell device architectures for space compliance
• Ultralight packaging strategies for space power
• Challenges beyond radiation tolerance and near-future focus

Louise Hirst formed the Space PV group at University of Cambridge in 2018 jointly in the Department of Physics and the Department of Materials Science and Metallurgy. Prior to this, she obtained her PhD from Imperial College in 2013, and was subsequently appointed National Academies Research Associate, Karles Fellow and Staff Scientist in the Optoelectronics and Radiation effects branch at the U.S. Naval Research Laboratory.

Her current research focuses on the development of photovoltaic systems for next generation space power applications, including satellite networks, space exploration and space based solar power. Translational research within her group looks at ultra-thin photonic integrated devices, novel III-V growth on graphene and radiation damage in space environments.

Ahmad Kirmani joined the School of Chemistry and Materials Science at the Rochester Institute of Technology (RIT) in 2023, where he leads the Interface and Structure in Printable Inorganic Electronics (INSPIRON) laboratory with a focus on printable electronics for terrestrial and space applications. Previously, as a postdoctoral researcher at the National Renewable Energy Laboratory (NREL), Ahmad led the perovskite space power research program exploring radiation effects in perovskite solar cells and developing space-compatible device architectures. His research has resulted in over 50 peer-reviewed journal articles on solution-processed semiconductor optoelectronics including colloidal quantum dots, metal oxides, and perovskites.

 

Tutorial PM4: Extending Metal Halide Perovskite Based PV Lifetimes

Instructor: Kelly Schutt, National Renewable Energy Laboratory, USA
Laura Schelhas, National Renewable Energy Laboratory, USA

Demonstrated field performance is probably the greatest remaining challenge for the commercialization of metal halide perovskite (MHP) based photovoltaic technologies. This tutorial explains both the fundamentals behind the many degradation modes in MHP-based PV cells and modules and the practical strategies attendees can employ to prolong device lifetimes. We will also touch on current approaches and best practices in reliability testing, including outdoor field testing and indoor accelerated testing approaches for modules.

Specific topics include phase and impurity driven instabilities in the MHP, additives and surface treatments, interfacial reactions, considerations for contact materials, and environmental and operational stresses.

Kelly Schutt is a staff scientist at the National Renewable Energy Laboratory (NREL). His current research interests are in perovskite photovoltaics for satellite applications, perovskite radiation detection, and the long-term stability of perovskite PV. Kelly received his Ph.D. in Condensed Matter Physics from the University of Oxford in 2020, where he studied as a Marshall Scholar with Professor Henry Snaith. His graduate work focused on improving the performance of perovskite solar cells through novel charge selective contacts and interfaces. In 2020, Kelly joined NREL under a Director’s Postdoctoral Fellowship and generated intellectual property for perovskite radiation detectors before being selected for Energy I-CORPS, an intensive, hypothesis-driven commercialization program requiring 75 industry interviews. At NREL Kelly has received awards for key contributions to the laboratory and new business development.

Laura Schelhas is a senior scientist and the manager of the Hybrid and Nanoscale Materials Chemistry Group at the National Renewable Energy Laboratory (NREL). Her current research interests are focused on the intersection between PV reliability, emerging new technologies, and materials characterization. Laura also serves as the executive director of the US-MAP consortium, and deputy director of the PACT center. She is also the technical lead for the partnership between NREL and Fortescue Future Industries. Laura received her Ph.D. in chemistry from the University of California, Los Angeles in 2013 where she studied the influence of nanoscale architecture on the materials properties in magnetic and magnetoelectric materials. In 2014, she accepted a postdoctoral position at the Stanford Synchrotron Radiation Lightsource (SSRL) at SLAC National Accelerator Laboratory using in-situ and operando methods to study both the formation and degradation of optoelectronic materials. She became staff at SLAC in the Applied Energy Division in 2016 and served as the deputy director of the division and the group leader for the Grid Integration, Systems & Mobility (GISMo) Lab before taking her current position at NREL in 2020.

 

Tutorial PM5:PV Systems Modeling with Python, an Interactive Introduction

Instructor:
Silvana Ovaitt, National Renewable Energy Laboratory, USA
Madison Ghiz, DNV, USA

Description
From development to deployment and management of assets, PV modeling is an exciting area with challenges and the use of big data from weather to performance monitoring. Modeling tools for all aspects of photovoltaic systems are rapidly growing, and there are solutions for many research questions you might want to explore. Python is becoming one of the scientific languages of choice, and many open-source tools are now available for PV modeling. This tutorial will focus on teaching attendees PV modeling in python through PVlib.

In this interactive tutorial, we will go from getting acquainted with some common data used or measured in PV systems (i.e., weather) to modeling the AC energy output of a single-axis tracker system. This includes learning and simulating sun position, plane-of-array irradiances, single-diode models, temperature models, and inverter output. We will review common vocabulary around python and common PV data aggregation by hour, week, month, and visualization. The tutorial will finalize with an overview of other available open-source tools for other aspects of modeling PV systems and novel ideas on data science in the PV field.

It is highly recommended attendees of this tutorial bring their laptops. No pre-installed software is needed.

Silvana Ovaitt (nee Ayala Pelaez) is a researcher at NREL working with the performance and reliability group on bifacial photovoltaic (PV) technology. Her focus is on bifacial PV optical and electrical performance and modeling, as well as Circular Economy. As part of her research, she enjoys developing open-source tools to explore and teach PV science. She is also the PI for the Hands-on PV Experience (HOPE) Workshop for PhD students at NREL. She has a PhD in electrical and computer engineering from the University of Arizona, and a master's degree in optical sciences at the same university.

Madison Ghiz is a solar energy analyst at DNV and part of the special projects team in energy assessment. Madison has been working in solar energy for the past 3 years, and recently has supported work on energy assessment validation, HMC, and SolarFarmer. Before joining DNV, Madison earned a Masters degree at Scripps Institution of Oceanography in geoscience, where her research focused on atmospheric physics driving Antarctic surface melt.