TUTORIALS

Tutorials are a fun and educational tradition of the IEEE-PVSC Annual Conference. These extended sessions will take place the Sunday before the conference event dates. Tutorials give a deep insight into selected research & development topics and serve both as an expert review of the field for all, as well as an introduction for newcomers. The tutorials are given by some of the most recognized and experienced scientists in the field. All tutorials come with a set of slides which are an indispensable source of information that you will not find anywhere else!

Tutorial sessions will take place on Sunday, June 5, 2022.
AM Tutorials will start at 9am Eastern Time and PM Tutorials will start at 1pm Eastern Time.

Tutorial Sessions

Tutorial AM1: Fundamentals of Photovoltaics
Tutorial AM2: Cell and Module Characterization
Tutorial AM3: Powering the World with Solar: What is Still Needed Before we can Declare Victory
Tutorial AM4: Tandems / Multijunction Solar Cells
Tutorial AM5: Crystalline Silicon, Chalcogenide, and III-V Photovoltaics

Tutorial PM1: Reliability & Durability of Photovoltaic Modules
Tutorial PM2: Storage & Grid Integration/Energy Systems Modeling
Tutorial PM3: Quantitative Defect Spectroscopy of PV Cells
Tutorial PM4: Foundations of Future Photovoltaic Technologies: Perovskite & Organic PV
Tutorial PM5: Cost & Technology Trends Analysis: PV Supply Chains & PV Systems Coupled with Storage

Click below to learn more about each tutorial.


Tutorial AM1: Fundamentals of Photovoltaics

Instructor:
N.J.Ekins-Daukes, UNSW Sydney, Australia

Tutorial Description
The tutorial will begin by surveying the properties and availability of sunlight, introducing the necessary measures and some commonly used data sources. A simple thermodynamic model for solar power conversion will be established to place an upper bound to the conversion efficiency. It will then be shown that using a semiconductor absorber leads to the usual measures for solar cell performance, short-circuit current, open circuit voltage and fill factor and introduces additional constraints to photovoltaic power conversion leading to the Shockley-Queisser efficiency limit. The carrier transport and recombination processes that are present in practical solar cells will be discussed in the context of Shockley’s diode equation. Analytical models for solar cell dark current, quantum efficiency and reciprocity between absorption and emission will be introduced.

Having established a conceptual framework for PV devices the present laboratory status and manufacturing of several solar cell technologies will be surveyed, including those made from crystalline silicon, III-V, CdTe, CIGS, organic and perovskite in both single junction and tandem architectures. The application of these solar cells in PV power systems will be discussed together with the economic and life-cycle metrics that are commonly used to determine the feasibility and desirability. The tutorial will conclude with a brief perspective on possible future scenarios for PV power generation and technological evolution.

Dr N.J.Ekins-Daukes (Ned) is presently Associate Professor at the School of Photovoltaic & Renewable Energy Engineering at UNSW Sydney in Australia. He received his first degree in Physics & Electronics from the University of St Andrews in Scotland and PhD in Solid State Physics from Imperial College London in 2000. He subsequently worked as a JSPS research fellow at the Toyota Technological Institute in Japan, he held full-time academic positions at the University of Sydney and then Imperial College before taking up his present position at UNSW Sydney. His research aims to fundamentally increase the efficiency of photovoltaic solar cells towards the ultimate efficiency limit for solar power conversion of 87%.











Tutorial AM2: Cell and Module Characterization





Instructors:
Karsten Bothe, ISFH Calibration and Test Center (CalTeC), USA
Ronald Sinton, Sinton Instruments, USA

Tutorial Description
This tutorial covers the testing of solar cell cells and modules. Special emphasis is placed on best practices for silicon device testing in R&D and calibration laboratories. The special challenges of contacting and sensing of bare cells are addressed and concepts for measurement comparability are presented. In addition to the basic methods of determining the spectral responsivity of solar cells and measuring their current-voltage characteristics, camera-based luminescence measurements are also discussed. The methods for laboratory calibration and testing of cells will be compared and contrasted with production requirements and analysis. In the area of module measurements, strategies for minimizing uncertainties will be presented, based on the fundamentals of the equipment and also the device physics behind concepts such as the effects of cell capacitance, illumination non-uniformity, cell mismatch, and the module circuits including bypass diodes. Approaches to data-based assessment of measurement uncertainties will be described.

Karsten Bothe studied Physics with the TU Braunschweig, Germany; the University of Sussex,Brighton, U.K.; and the University of Oldenburg, Germany. He received the Diploma degree in physics from the University of Oldenburg. Afterwards, he joined the Institute for Solar Energy Research Hamelin (ISFH), Emmerthal, Germany, and received the Ph.D. degree in Oxygen-related trapping and recombination centres in boron-doped crystalline silicon in 2006 from the University of Hannover, Hannover, Germany. After being with the Nara Institute of Science and Technology, Nara, Japan, as a research fellow, in 2007 he became head of the solar cell characterization group at the ISFH. After supervising pioneering work on camera-based luminescence imaging techniques for the characterization of silicon wafers and solar cell he worked on the development of combined algorithms and measurement techniques for a quantitative local loss analysis of crystalline silicon solar cells. His current research interest is the calibrated measurement of the characteristic parameters of crystalline silicon solar cells. Since 2016 he is head of the solar cell calibration laboratory at the ISFH Calibration and Test Center (CalTeC).

Ron Sinton did his PhD work at Stanford University developing 28%-efficient silicon concentrator cells and 23% efficient backside-contact one-sun cells. He then continued this work by adapting the fabrication processes to be more industrial as a founding member of SunPower Corporation. After founding Sinton Instruments in 1992, he focused the company on bringing the systematic device physics approach that was used to develop very high-efficiency silicon solar cells to the design of test and measurement instruments for the broader Silicon field. He was involved in the development of many techniques that are commonly used today, such as the Suns-Voc technique and the methodology for extracting and reporting implied voltage from lifetime data. Sinton Instruments provides metrology for nearly all of the research labs and production facilities working in silicon PV technology. Ron enjoys blurring the boundaries between metrology and device physics in order to report parameters that are key inputs to physical models. He participates in conference program organization, especially the IEEE PVSC (1987-2008) and the annual NREL Silicon Workshop (1994-present). Ron received the Cherry Award at the 2014 IEEE PVSC.











Tutorial AM3: Powering the World with Solar: What is Still Needed Before we can Declare Victory

Instructor:
Sarah Kurtz, University of California Merced, USA

Description
Solar has made tremendous progress in reducing costs for large-scale systems, but it is far from providing a large fraction of the world’s electricity and even farther from providing a large fraction of the world’s energy. How far has PV come and how much farther to go? If we attempt to reach zero emissions by 2050, how fast will PV need to grow? After the pandemic, supply issues have hit many industries, including PV - will these get worse or be short transients? What new technology will be needed? What sustainability challenges can we expect? What policy will be needed to get there? When tackling these questions, one must consider how much energy will be needed and what fraction of that will be supplied by PV. Although historical relative growth rates could easily enable PV to meet the 2050 goals, as PV grows, prediction of the growth rate of all elements of the supply chains will become increasingly important to avoid shortages and oversupplies. A rapid transition of the energy system by 2050 can only happen as a result of strong policy choices; many companies and countries are embracing that challenge. In the last years, we’ve seen how quickly the world can change. This tutorial will attempt to take a ride into our energy future - looking for a way to make it be a smoother ride than what the pandemic has just taken us through!

Sarah Kurtz obtained her PhD in 1985 from Harvard University and now works at the University of California Merced after more than 30 years working at the National Renewable Energy Laboratory, in Golden, CO. She is known for her contributions to developing multijunction, GaInP/GaAs solar cells, supporting the Concentrator Photovoltaic (PV) industry, and leading efforts on PV performance and reliability. Her work has been recognized with a jointly received Dan David Prize in 2007, the Cherry Award in 2012, C3E Lifetime Achievement Award in 2016, and induction into the National Academy of Engineering in 2020. At the University of California Merced she is working both to help the university grow and to support the Energy Transition through a variety of studies, including a current study on long-duration storage.











Tutorial AM4: Tandems / Multijunction Solar Cells





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 multijunction 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 the III-V alloy system and the various techniques that are available for growing these highly crystalline semiconductors. 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 multijunction 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 in the High Efficiency Crystalline Photovoltaics group at the National Renewable Energy Laboratory, in Golden, Colorado, where he works on III-V multijunction solar cells for terrestrial and space power generation, thermophotovoltaics for energy storage, and hydrogen generation by photoelectrochemical water splitting.

Emily Warren is a staff scientist in the High Efficiency Crystalline Photovoltaics group at the National Renewable Energy Laboratory, in Golden, Colorado, where she focuses 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 AM5: Crystalline Silicon, Chalcogenide, and III-V Photovoltaics

Instructor:
 Angus Rockett, Colorado School of Mines, USA

Description
This tutorial provides a brief review of the current status, research challenges, and potential of chalcogenide-based thin film, silicon, and III-V photovoltaic materials and devices. Due to time restrictions, some details may be limited. The tutorial will include a brief comparison of the status and applications of devices based on these three classes of materials. The tutorial begins with a review of current silicon devices including common device structures, novel processing methods, selective contact technologies, point contacts, silver and non-silver based interconnects, and the potential of tandem devices using silicon cells as the low-gap cell. Chalcogenide devices include both CdTe and CuInSe2 and related materials and alloys. These were largely responsible for the drop in the price of PV and have enormous potential and face enormous challenges. In addition to the single-junction device potential it is likely that these materials will ultimately have to be produced as multijunctions to compete on overall efficiency. Finally, III-V photovoltaics provide the highest single and multijunction efficiency devices but are typically expensive to produce. A brief discussion of those devices and their potential is considered.

Angus Rockett is a Professor in the Department of Metallurgy and Materials Engineering and the Colorado School of Mines and an Emeritus Professor in the Department of Materials Science and Engineering at the University of Illinois. He was President in 2011 and is a Fellow of the American Vacuum Society. He was the General Chair of the IEEE Photovoltaic Specialists Conference in 2016 and has held many positions with both the PVSC and the AVS. Since January 2021 he has been the Editor in Chief of the IEEE Journal of Photovoltaics. He received his B.S. in physics from Brown University and his Ph.D. in metallurgy from the University of Illinois. His research involves defects in semiconductors, primarily focused on synthesis and characterization and theory and modeling of solar cell materials. He has applied a wide variety of materials microanalysis methods to study semiconductors. His group has done density functional theory, continuum elasticity, lattice Monte Carlo, and drift-diffusion modeling of materials and devices. He has also worked with reactive sputtering of nitrides and other materials. He is the author of one book (The Materials Science of Semiconductors), five book chapter contributions, more than 170 publications in archival journals, holds three sputtering- and/or photovoltaics-related patents, and has given more than 140 invited talks. He teaches courses in electronic materials and processing in addition to general materials science courses. He has presented short courses and tutorials in sputtering, materials microanalysis, and solar cells and solar cell materials for a variety of professional societies and organizations around the world.











Tutorial PM1: Reliability & Durability of Photovoltaic Modules

Instructor:
John Wohlgemuth, PowerMark Corporation, USA

Description
This tutorial will describe the industry’s field experiences with early PV modules and how identification of failure modes led to the development of accelerated stress tests that have been used to develop more reliable and durable products. Proper application of these accelerated stress tests (humidity freeze, thermal cycling, damp heat, mechanical load, etc.) through module qualification and safety testing (IEC 61215 and IEC 61730) along with implementation of quality management systems in module manufacturing led to rapid improvements in module lifetimes and extensions of the product warranties. The tutorial will review recent research on improving reliability and durability with its ultimate goal of developing a method for predicting module lifetimes.

John Wohlgemuth is the Executive Director of PowerMark Corporation where he serves as the Technical Advisor to IEC Technical Committee 82 on Photovoltaics. He retired from the National Renewable Energy Laboratory where he served as a Principle Scientist in PV Reliability from 2010 until 2017. While at NREL he was responsible for establishing and conducting research programs to improve the reliability and safety of PV modules. Before joining NREL Dr. Wohlgemuth worked at Solarex/BP Solar for more than 30 years. His PV experience includes cell processing and modeling, Si casting, module materials and reliability, and PV performance and standards. Dr. Wohlgemuth was a member of working group 2 (WG2), the module working group within TC-82, the IEC Technical Committee on PV from 1986 to 2017 and was convenor of the group for more than 15 years. Dr. Wohlgemuth was a member of the Steering Committee for the PV Module QA Task Force (PVQAT) and is a member of the STP for UL 1703. He is the author of the book Photovoltaic Module Reliability published by Wiley in 2020. Dr. John Wohlgemuth earned a Ph.D. in Solid State Physics from Rensselaer Polytechnic Institute.

 









Tutorial PM2: Storage & Grid Integration/Energy Systems Modeling

Instructor:
Marta Victoria, Aarhus University, Denmark

Description
Throughout the last decade, a higher capacity of solar PV was installed globally than any other power-generation technology, and in 2022 we expect to reach the milestone of 1 TW of installed global PV capacity. With solar PV providing the cheapest electricity in many parts of the world, we will see increasingly high penetration of solar in the grids. This tutorial will focus on the challenges of energy systems with very high solar and wind penetration, and how energy modelling can help us to anticipate and mitigate those challenges.

The role of different balancing strategies and how to combine them will be discussed. This includes alternative storage technologies to smooth in time renewable fluctuations and the extension of transmission links to benefit from regional integration. On top of that, coupling the power grid with other sectors such as heating, or transport not only enables a fast decarbonization of those sectors but also brings additional flexibility. The main concepts and principles of energy modelling will be reviewed together with the existing modelling approaches and their main limitations. Special emphasis will be placed on open energy models that ensure transparency and reproducibility.

Marta Victoria did her PhD on high-efficiency photovoltaic modules at the Technical University of Madrid. Currently, she works at the Department of Mechanical and Production Engineering at Aarhus University (Denmark), where she teaches MSc courses on Solar Photovoltaics and Energy System Modelling. Her research focuses on the modelling of large-scale energy systems paying special attention to the role of solar photovoltaics. In this multidisciplinary approach, she combines engineering, meteorology, optimization theory, complex networks, economics, and environmental policy to design strategies for timely decarbonization. She is a member of the Open Energy Modelling Initiative, which aims to promote openness and transparency in energy system modelling, and she co-develops the open-source energy model PyPSA.











Tutorial PM3: Quantitative Defect Spectroscopy of PV Cells

Instructor:
Aaron Arehart, The Ohio State University, USA

Description
This tutorial will focus on methods to evaluate the accuracy of capacitance-based measurements, optical and thermal-based quantitative defect spectroscopy, and high-resolution mapping of traps laterally and vertically in solar cell materials and devices.  Whether Si, CIGS, space III-V, CdTe, perovskites, or other solar cell technology, all suffer from traps either at beginning of life, after harsh conditions like potential induced degradation (PID), after irradiation, contamination or migration of mobile atoms, or even after years of normal operation.  These traps act as compensating centers, recombination/generation centers, or leakage pathways, for example, so when they reach critical levels they influence any or all of the cell parameters including VOC, JSC, and FF.  Additionally, these effects can be static or dynamic.  In the latter case, traps occupation can depend on previous biasing, recent light exposure, or other external factors and will exhibit a time dependent behavior based on the trap occupation.  This has been demonstrated in CIGS for JSC and VOC metastabilities.   Thus, tracking trap densities as a function of growth conditions, accelerated life testing, radiation fluence and particle type, and other stressors is necessary to understand the role of traps.  That said, even presumed simple things like doping extracted from capacitance-voltage measurements are easily complicated by high conductance, back barriers, and shallow traps leading to erroneous extracted doping concentrations in some cases.  This tutorial will start at what is needed for accurate capacitance measurements, possible problems and solutions including fast C-V to avoid traps influencing extracted doping density; progress to deep level transient and optical spectroscopies (DLTS and DLOS) theory, advantages, and disadvantages; and finally end of with examples traps influencing solar cell performance and stability.


Aaron Arehart
is an Associate Research Professor of Electrical and Computer Engineering at The Ohio State University.  He has over 20 years of expertise in characterizing and identifying traps in semiconductor materials ranging from 0.3 eV to almost 6 eV bandgaps.  In the area of photovoltaics, Aaron has worked on II-V space solar, CIGS, Si, perovskites, and CdTe.  Aaron built and manages the largest known deep level transient and optical spectroscopy lab in the world, which are custom built and programmed. He also has developed new and refined existing defect spectroscopy techniques such as scanning-deep level transient spectroscopy for nanometer-scale mapping of specific traps concentrations.    Aaron is author of more than 100 journal and proceedings published, has received several awards including OSU’s Lumley Research Award, currently is PI or co-PI of four DoE projects, and consults with many DoD and DoE-involved companies.











Tutorial PM4: Foundations of Future Photovoltaic Technologies: Perovskite and Organic PV

Instructor: Joe Berry, National Renewable Energy Laboratory, USA

Description
This tutorial focusses on state of the art in metal halide perovskite photovoltaics. Current material challenges for metal halide perovskite photovoltaics will be discussed and compared to current issues in challenges in other nascent thin-film technologies (e.g. organic photovoltaics). Key considerations of device physics as well as how absorber and contact material choices can make or break the success of these technologies will be covered. Advances in material and device architectures will also be discussed.

Joseph J Berry is a Senior Research Fellow at NREL and member of NREL's National Center for Photovoltaics, where he is the team lead of the hybrid perovskite solar cell program. He conducts research on charge transport at the interface in all-inorganic and organic/inorganic interfaces for optoelectronic devices and systems. Past work includes contributions to development of contacts for organic photovoltaics and optoelectronics more broadly. He is also a Fellow of the Renewable and Sustainable Energy Institute (RASEI) a joint institute between NREL and the University of Colorado. He is also a professor in the Department of Physics at the University of Colorado.

 









Tutorial PM5: Cost & Technology Trends Analysis: PV Supply Chains & PV Systems Coupled with Storage



Instructors:
Michael Woodhouse, National Renewable Energy Laboratory, USA
Vignesh Ramasamy, National Renewable Energy Laboratory, USA

Description
This tutorial will highlight the most recent efforts from the National Renewable Energy Laboratory (NREL) to track solar photovoltaic (PV) technology trends and manufacturing costs, project levelized cost of electricity (LCOE), and project levelized cost of solar plus storage (LCOSS) for systems across the globe.

We will begin with an overview of the global PV supply chain and 2021 benchmark input data for NREL’s crystalline silicon (c-Si) and thin film PV module manufacturing cost models. The framework that we follow and will review during this tutorial provides a methodology to prepare bottom-up manufacturing cost models including the items within the U.S. Generally Accepted Accounting Principles (GAAP) and the International Financial Reporting Standards (IFRS). For the polysilicon, wafer, cell conversion, and module assembly steps of the c-Si supply chain, and for thin film modules, we will review input data and methods useful for calculating the costs of goods sold (COGS); research and development (R&D) expenses; and sales, general, and business administration (S, G, &A) expenses. This 2021 benchmark analysis is compiled for state-of-the-art c-Si and thin film module manufacturing.

We will also review methods for our 2021 system benchmark costs calculations and LCOE technoeconomic analysis of PV systems and solar plus storage systems. Next generation technologies that lower PV manufacturing and installation costs, reduce operations and maintenance (O&M) expenses, and improve system energy yield will also be highlighted. Techniques for comparing LCOE performance will also be reviewed. We look forward to sharing NREL's extensive work in these areas and discussing ideas for future directions.

Michael Woodhouse is a senior analyst and the co-principal investigator with Robert Margolis for NREL’s solar and storage technoeconomic analysis portfolio, which currently includes work in designing and developing bottom-up manufacturing cost modelling software, conducting PV system levelized cost of electricity (LCOE) and levelized cost of solar plus storage (LCOSS) calculations, tracking current global solar and storage policy issues, and identifying research and development priorities for an accelerated global transition to clean and sustainable energy. Dr. Woodhouse also serves as the Associate Editor for Energy Economics and Policy for the Journal of Renewable and Sustainable Energy and on the Steering Committee for the International Technology Roadmap for Photovoltaics (ITRPV).

Vignesh Ramasamy is a member of the Distributed Systems and Storage Group in the Integrated Applications Center at National Renewable Energy Laboratory and he has 5+ years of experience conducting techno-economic analysis of PV and Energy Storage applications. At NREL his primary focus is on building and validating the system cost models for different technologies.