SUNLAB News
Fulcrum interview with SUNLAB student
The Fulcrum, the University of Ottawa’s English-language student newspaper, recently interviewed PhD candidate Erin Tonita about her Joule publication. Erin explains the difference between bifacial and conventional solar panels and demistifies the general illumination method detailed in her paper. Click here for the full interview.
U of O researcher suggests novel measuring method for bifacial solar panels, The Fulcrum, September 21, 2023.
New publication from the SUNLAB: Journal of Materials Chemistry C
A collaboration between the Lessard Research Group and the SUNLAB resulted in a recent publication first-authored by MSc candidate Nicholas Dallaire, in the Journal of Materials Chemistry C. In this manuscript, the authors explore the effect of selective wavelength exposure on single walled carbon nanotube-based thin film transistors.
The fabrication of high-purity semiconducting single-walled carbon nanotubes (sc-SWNTs) often utilizes conjugated polymers to isolate the semiconducting from the metallic species. These polymers preferentially sort and disperse certain sc-SWNT chiralities and often remain wrapped around sc-SWNTs during device integration. In this study, the authors expose three different SWNT-based thin film transistors, each with a different dispersion polymer to three different laser wavelengths selected to overlap both the optical transitions of the sc-SWNTs and the polymer absorption.
The authors show that two phases emerge. An initial soak, where the devices change after an initial exposure which permanently increases the mobility. The second phase, the photo cycling, produces repeatable device performance between exposures “On Cycling” and post exposures “Off Cycling”, such as consistent threshold voltage shifts with an overall average shift of 3.6±0.6 V, highly dependent on the wavelength and polymer, thus providing greater motivation for tunable SWNT-based thin film transistor photodetectors. Although the general behavior is shared among most types and wavelengths, discrepancies in intensity emerge, especially when exciting the polymer. Hence, the authors show the importance of polymer choice when considering desirable parameters, in addition to their selected SWNT chirality. The results of this research will lead to improvements in SWNT-based thin film transistors. Applications include organic photodetectors.
Click here for the full article.
Nicholas J. Dallaire, Brendan Mirka, Joseph G. Manion, William J. Bodnaryk, Darry Fong, Alex Adronov, Karin Hinzer, and Benoît H. Lessard, Conjugated wrapping polymer influences on photoexcitation of single-walled carbon nanotube-based thin film transistors, J. Mater. Chem. C 11, 9161-9171 (2023) DOI: 10.1039/D3TC01484C
SUNLAB at PVSC
Earlier this month, SUNLAB students and researchers attended the 50th IEEE Photovoltaics Specialists Conference in San Juan, Puerto Rico. Postdoctoral fellow Mathieu de Lafontaine, PhD physics candidates Gavin Forcade and Erin Tonita, and PhD electrical engineering Mandy Lewis presented results on a wide range of topics including photonic power converters, bifacial photovoltaic systems, and betavoltaics. For a full list of SUNLAB presentations, see our Conference Presentations page.
Congratulations to:
Mandy Lewis, for being awarded a Best Student Paper Award for Area 7 for the second year in a row;
SUNLAB friend Professor Jacob Krich for receiving the Napkin Award for his work as Area 1 Chair;
Mathieu de Lafontaine for Area 1 Best Poster nomination;
Erin Tonita and Gavin Forcade for being Best Student Presentation Award Finalists;
Gavin Forcade, Mandy Lewis and Erin Tonita for mentions in the Tuesday Daily Highlights;
Mathieu de Lafontaine for mention in the Thursday Daily Highlights.
The IEEE Photovoltaics Specialists Conference is the longest-running technical gathering for the photovoltaics industry. This year, it was held at the Puerto Rico Convention Center in San Juan, Puerto Rico, from June 11 to 16.
Karin Hinzer, Gavin Forcade and Mathieu de Lafontaine posing in front of Mathieu’s poster.
Mandy Lewis
Erin Tonita
Certificate for Mandy Lewis’s Best Student Paper Award.
Plaque for Jacob Krich’s Napkin Award.
SUNLAB at RQMP Grande Conférence
On Friday, June 9, SUNLAB members traveled to Sherbrooke, Québec, to attend the Grande conférence of the Regroupment québécois sur les matériaux de pointe (Québec Network Advanced Materials). SUNLAB director Karin Hinzer was the keynote speaker at the conference. Her talk covered new developments in solar energy and photonic power. PhD candidate Idriss Amadou Ali presented a poster entitled “Developing and packaging a near-IR on chip CO2 sensor”. Postdoctoral fellow Paige Wilson and MASc candidate Derrick Wu also attended the conference.
Idriss Amadou Ali presents his poster to conference participants.
From left to right: Idriss Amadou Ali, Karin Hinzer, Paige Wilson and Derrick Wu.
SUNLAB winter thesis defences
Congratulations to Trevor Coathup, Ras-Jeevan Obhi and Neda Nouri who defended their theses in the last few months! They received their diplomas this weekend at the spring convocation. You can now find their theses on ruor.uottawa.ca. Congratulations also to Idriss Amadou Ali, who recently started his PhD in electrical engineering at the SUNLAB. Idriss received a BSc Physics and BASc Electrical Engineering at the spring convocation.
Trevor Coathup, MASc Electrical Engineering, Effect of torque tube reflection on shading and energy yield in bifacial photovoltaic systems, DOI: 10.20381/ruor-29138
Ras-Jeevan Obhi, MASc Electrical Engineering, Characterizing and modelling quantum dashes for InP-based semiconductor lasers, DOI: 10.20381/ruor-28676
Neda Nouri, PhD Electrical Engineering, Design, modeling, and optimization of thin and ultra-thin photonic power converters operating at 1310 nm laser illumination, DOI: 10.20381/ruor-28539
From left to right: Karin Hinzer, Idriss Amadou Ali, Neda Nouri, and Ras-Jeevan Obhi.
SUNLAB students awarded scholarships
Congratulations to SUNLAB students Mandy Lewis, Erin Tonita, Victoria Jancowski and Nicholas Pulido on receiving prestigious scholarships to support their research.
PhD electrical engineering candidate Mandy Lewis and PhD physics candidate Erin Tonita were each awarded an Ontario Graduate Scholarship. This merit-based scholarship is available to graduate students in all disciplines of academic study. The Ontario Graduate Scholarships program is jointly funded by the Province of Ontario and Ontario universities.
BASc electrical engineering candidate Victoria Jancowski is spending the summer at the SUNLAB performing research on spectroradiometric standards for bifacial photovoltaic solar power. She was awarded a CSA Group Undergraduate Research Scholarship for a second year in a row. This scholarship aims to support undergraduate students in the pursuit of novel research related to standards.
BASc electrical engineering candidate Nicholas Pulido was awarded an Undergraduate Student Research Award from the Natural Sciences and Engineering Research Council of Canada. This scholarship is meant to nurture undergraduate students’ interest and fully develop their potential for a research career. This summer, Nicholas is studying the effects of artificial reflectors on bifacial photovoltaic systems using open-source view-factor models.
References
Ontario Student Assistance Program (retrieved June 9, 2023). Ontario Graduate Scholarship (OGS) Program: https://osap.gov.on.ca/OSAPPortal/en/A-ZListofAid/PRDR019245.html
CSA Group (retrieved June 9, 2023). CSA Group Undergraduate Research Scholarship: https://www.csagroup.org/csa-group-undergraduate-research-scholarship/
NSERC (retrieved June 9, 2023). Undergraduate Student Research Awards: https://www.nserc-crsng.gc.ca/students-etudiants/ug-pc/usra-brpc_eng.asp
New publication from the SUNLAB: Solar Energy
Led by PhD candidate Erin Tonita, SUNLAB researchers have published a new paper in Solar Energy, describing the optimal row spacing of tracked, south-facing fixed-tilt, and east-west vertical photovoltaic (PV) systems as a function of latitude up to 75°N.
Traditional guidelines for determining the layout of PV arrays were historically developed for monofacial fixed-tilt systems at low-to-moderate latitudes. As the PV market progresses toward bifacial technologies, tracked systems, higher latitudes, and land-constrained areas, updated flexible and representational guidelines are required. Old approaches, like the winter solstice rule where row spacing is selected to eliminate direct inter-row shading on December 21 at solar noon, are insufficient to capture the nuance of deployment planning, where practical and economical constraints vary widely both geographically and temporally.
Using their 3D view-factor PV system model, DUET, SUNLAB researchers optimized row spacing for tracked, fixed-tilt, and vertical arrays with both bifacial and monofacial technologies from 17-75°N with acceptable inter-row shading losses of 5-15%. Results were generalized for an arbitrary collector area by presenting the ground coverage ratio (GCR – i.e., the ratio between PV collector length and row pitch). Formulae for calculating the appropriate GCR of a PV deployment between 17-75°N are provided in the article.
GCR varies widely between 0.15-0.68 for fixed-tilt systems compared to 0.17-0.32 for HSAT systems, both with a strong latitude-dependence. Similarly, the optimal tilt of fixed-tilt arrays varies widely from 7° above latitude-tilt to 60° below latitude-tilt, depending on the latitude and GCR. Vertical systems are less sensitive to latitude, with GCR varying from 0.10-0.16 between 17-75°N. In all cases, it was demonstrated that tracked and fixed-tilt PV arrays should have similar GCRs >55°N. Less than 55°N, tracked systems are more sensitive to row-to-row shading losses.
SUNLAB authors additionally found that it is reasonable to approximate the row spacing of bifacial arrays as equivalent to monofacial arrays, with bifacial modules of 96% bifaciality requiring GCRs lower by 0.03 on average than monofacial modules.
Overall, this research provides updated representational and flexible guidelines for PV system design that better suit the expanding PV sector.
Click here for the full article.
E. M. Tonita, A. C. J. Russell, C. E. Valdivia, and K. Hinzer, Optimal ground coverage ratios for tracked, fixed-tilt, and vertical photovoltaic systems for latitudes up to 75°N, Sol. Energy 258, 8-15 (2023). DOI: 10.1016/j.solener.2023.04.038
In the media:
New guidelines for inter-row spacing of PV power plants, pv magazine, July 6, 2023
Graphical abstract
uOttawa, University of Würzburg scientists make breakthrough in study of light
Physicists and physical chemists from the University of Würzburg and the University of Ottawa have solved a decades-old problem of distinguishing single and multiple light excitations.
“Laser light is widely used to learn about many kinds of materials using a broad set of techniques called spectroscopy,” says uOttawa physics and SUNLAB professor, and study co-author Jacob Krich. “We have developed a new spectroscopic method that is easy to apply and gives access to information about what happens when materials absorb more than one photon.”
The interaction of laser light with all kinds of materials is used to learn about biological, chemical and solid-state systems. Frequently, researchers are interested in the behaviour of materials after they’ve been “excited” just once — that is, after they absorb a single photon. To reach this limit, scientists turn down the power in the laser, which makes signals harder to measure and noisier.
The method developed by the team of physicists and physical chemists has a broad range of applications. It would be particularly useful in studying systems with closely-packed light absorbers, such as those found in organic materials or biological light-harvesting complexes.
Krich and his colleagues believe their method is easy to implement for any spectroscopic research group. He highlights the team’s finding hidden structure in the well-known interaction of light with matter.
The study used the “transient absorption” method, with multiple laser powers and a newly-derived formula to systematically separate the effects from just one excitation from those from multiple excitations — up to six — in samples.
The scientists intend to expand the method and use it to analyze energy transport in new photovoltaic materials, which convert light energy into electrical energy.
The study, “Separating single- from multi-particle dynamics in nonlinear spectroscopy” is published in Nature.
P. Malý, J. Lüttig, P. A. Rose, A. Turkin, C. Lambert, J. J. Krich, and T. Brixner, Separating single- from multi-particle dynamics in nonlinear spectroscopy, Nature 616, 280–287 (2023). DOI: 10.1038/s41586-023-05846-7
SUNLAB Spin-off Enurgen Selected for Prestigious Accelerator
Congratulations to SUNLAB spin-off company Enurgen for being selected as one of 10 companies out of 600 applicants to participate in the Equinor & Techstars Accelerator in Oslo, Norway. Enurgen is a start-up born from the SUNLAB’s work in bifacial cell-to-system modelling. It is helping to bring about the global transition to a zero-carbon future by leveraging its advanced modelling software to help generate clean, renewable, sustainable energy to power today’s electric grids. The start-up is made up of former and current graduate students, researchers, and professors from the University of Ottawa.
The Enurgen team (from left to right): Elias Hussary, Chris Valdivia, Kibby Pollak, Ras-Jeevan Obhi, Henry Schriemer and Karin Hinzer
New Publication from the SUNLAB: Optics Express
SUNLAB has published a new paper in Optics Express, first-authored by MASc candidate Trevor Coathup. This paper quantifies the impact of torque tube reflections in tracked bifacial photovoltaic systems over a typical meteorological year in Livermore, California, USA.
Among the racking elements of bifacial photovoltaic single-axis tracked systems, the torque tube introduces the most shading and reflection, increasing irradiance nonuniformity and electrical mismatch loss. Ray tracing bifacial PV modeling software can capture these effects at a high computational cost, and two-dimensional or three-dimensional view factor models can estimate their impacts with shading factors to iterate through simulations more quickly. DUET, SUNLAB's three-dimensional view factor model, which accounts for detailed shading using ray-object intersection, can be expanded to include reflections from racking elements, specifically the torque tube, and balance the accuracy-computational intensity tradeoff.
We simulate the impact of torque tube reflection on irradiance, electrical mismatch, and total energy yield based on sun position and sky condition for central bifacial photovoltaic modules on one-in-portrait (1P) and two-in-portrait (2P) single-axis trackers. We extract the torque tube reflection using a ray tracing model and introduce it as an additional irradiance source in DUET to assess the impact of torque tube reflection in such a model.
Despite the gap between modules allowing for more incident illumination on the torque tube in the 2P system, the relative impact of the torque tube reflection is similar, and can be larger in the 1P system for low irradiance conditions. Torque tube reflection increases annual irradiance in 1P and 2P systems by 0.17% and 0.30%, respectively. Overall, torque tube reflection increases the predicted instantaneous energy yield by up to 0.8% and 0.4%, and the annual energy yield by 0.11% and 0.18% in 1P and 2P system, respectively.
Click here for the full article.
T. J. Coathup, M. R. Lewis, A. C. J. Russell, J. E. Haysom, C. E. Valdivia, and K. Hinzer, Impact of torque tube reflection on bifacial photovoltaic single axis tracked system performance, Optics Express 31(4) (2023). DOI: 10.1364/OE.481301
New Publication from the SUNLAB: Applied Physics Letters
In a new paper published in Applied Physics Letters, recent SUNLAB graduate Ras-Jeevan Obhi, MASc, and a collaborative team between SUNLAB and National Research Council Canada researchers, have studied how quantum dash morphology and composition can be used to tune the emission wavelength of semiconductor quantum dash lasers. This analysis of nanoparticle arrays using atomic force microscopy and simulations of single quantum dashes provides valuable information for future designs of quantum dash lasers emitting at 1550 nm for next generation optical networks. This work is part of the TERAQD project, which is funded by the High-throughput and Secure Networks Challenge Program from National Research Council Canada.
Click here for the full article.
R.-J. K. Obhi, S. W. Schaefer, C. E. Valdivia, J. R. Liu, Z. G. Lu, P. J. Poole, and K. Hinzer, Indium arsenide single quantum dash morphology and composition for wavelength tuning in quantum dash lasers, Appl. Phys. Lett. 122(051104) (2023). DOI: 10.1063/5.0133657
New Publication from the SUNLAB: Joule
SUNLAB researchers have developed a new method for measuring the solar energy produced by bifacial solar panels, the double-sided solar technology which is expected to meet increased global energy demands moving forward.
Published in the journal Joule, this study from the SUNLAB team in the Faculties of Engineering and Science proposes a characterization method that will improve the measurement of bifacial panels indoors by considering external effects of ground cover such as snow, grass and soil. This will provide a way to consistently test bifacial solar panel performance indoors that accurately represents how the panels will perform outdoors.
With bifacial photovoltaics expected to provide over 16% of global energy demand by 2050, the SUNLAB’s methodology will improve international device measurement standards which currently do not distinguish between ground cover.
“Our proposed characterization method, the scaled rear irradiance method, is an improved method for indoor-measuring and modelling of bifacial devices that is representative of outdoor environmental conditions,” explains Erin Tonita, lead author and a Physics PhD student studying under Professor Karin Hinzer, whose research involves developing new ways to harness the sun’s energy.
“Incorporating this new method into future bifacial standards would provide a consistent methodology for testing bifacial panel performance under ground conditions including snow, grass, and soil, corresponding to globally varying illumination conditions.”
Photovoltaics is the study of converting solar energy into electricity through semiconducting materials, such as silicon. In bifacial solar panels, the semiconducting material is wedged between two sheets of glass to allow for sunlight collection on both sides, with one side typically angled towards the sun and the other side angled towards the ground. The additional light collected by bifacial solar panels on the rear-side offers an advantage over traditional solar panels, with manufacturers touting up to a 30% increase in production compared to traditional solar panels. Bifacial solar panels are also more durable than traditional panels and can produce power for over 30 years.
"Implementation of this method into international standards for such panels can enable predictions of outdoor bifacial panel performance to within 2% absolute”, says Tonita, who expects the benefits of this methodology to include:
Allowing comparisons between existing and emerging bifacial technologies.
Enhancing performance via ground cover specific design optimization.
Increasing solar panel deployments in non-traditional markets.
Reducing investment risk in bifacial panel deployments.
Improving bifacial panel manufacture datasheets.
“This method is of particular importance as renewable energy penetration increases towards a net-zero world, with bifacial photovoltaics projected to contribute over 16% of the global energy supply by 2050, or around 30,000 TWh annually,” says Hinzer, founder of SUNLAB and the University Research Chair in Photonic Devices for Energy and a Professor at the School of Electrical Engineering and Computer Science.
“This will extend current International Electrochemical Commission standards for bifacial solar panel measurements, enabling accurate comparisons of bifacial panel technologies, application-specific optimization, and the standardization of bifacial panel power ratings,” adds Hinzer, whose SUNLAB researchers worked in collaboration with Arizona State University for the study.
Housed at the University of Ottawa’s Centre for Research in Photonics, SUNLAB is the premier Canadian modelling and characterization laboratory for next generation bifacial, multi-junction, and concentrator solar devices.
E. M. Tonita, C. E. Valdivia, A. C. J. Russell, M. Martinez-Szewczyk, M. I. Bertoni, and K. Hinzer, A general illumination method to predict bifacial photovoltaic system performance, Joule 7(1), 5-12 (2023). DOI: 10.1016/j.joule.2022.12.005
In the media:
U of O researcher suggests novel measuring method for bifacial solar panels, The Fulcrum, September 21, 2023
Dwustronne panele fotowoltaiczne. Kolejny przełom w rozwoju słonecznej energii?, Świat OZE, February 6, 2023
Nouvelle méthode pour mesurer le rendement énergétique des systèmes PV bifaciaux, pv magazine, January 27, 2023
Nouvelle méthode pour mesurer avec précision la puissance des panneaux solaires à double face, Enerzine, January 25, 2023
New method to measure energy yield of bifacial PV systems, pv magazine, January 23, 2023
Double-sided solar panel breakthrough offers big boost for net-zero targets, Independent, January 18, 2023
Double-sided solar panel breakthrough offers big boost for net-zero targets, Yahoo!News, January 18, 2023
Double-sided solar panel breakthrough offers big boost for net-zero targets, MSN, January 18, 2023
Harnessing solar energy: New method improves readings of double-sided panels, Renewable Energy Magazine, January 18, 2023
Harnessing solar energy: New method improves readings of double-sided panels, ScienMag, January 18, 2023
Harnessing solar energy: New method improves readings of double-sided panels, TechNewsBoy, January 18, 2023
Harnessing solar energy: New method improves readings of double-sided panels, University of Ottawa Media, January 18, 2023
SUNLAB PhD Physics Student Erin Tonita, lead author of the new Joule publication.
SUNLAB Energy Futures Forum Celebrates 1 Year
In September, our Energy Futures Forum (EFF) celebrated it’s first birthday! SUNLAB students have been reading up on pathways to net-zero emissions and other topics in renewables integration, climate policy, and energy justice. We get together every couple of months to share, discuss, and ask questions. You can see some of the topics we’ve covered below:
- IEA Transport Emissions Summaries
- Embodied Carbon of PV
- Energy Subsidies in Canada and around the world
- Carbon Capture, Utilization and Storage
- IEA Net Zero by 2050 Report
- Fed. Gov. 2030 Emissions Reduction Plan
- NREL/DOE Solar Futures Study
- COP26 Emissions Targets by Country
- 2021 Federal Election Platforms on Energy/Climate
The EFF is winding down for the winter break, but we’ll be back in the new year!
New Publication from the SUNLAB: IEEE Journal of Photovoltaics
SUNLAB has published a new paper in IEEE Journal of Photovoltaics, first-authored by postdoctoral fellow Dr. Meghan Beattie. In collaboration with researchers at the Fraunhofer Institute for Solar Energy Systems ISE in Germany, the SUNLAB team studied two highly efficient O-band photonic power converter designs, demonstrating their potential for powering devices requiring less than 250 mW with an appropriate illumination profile. This work is part of the AIIR-Power (Artificial Intelligence Enhanced Design and Manufacturing of Infrared Photonic Power Converters for Power and Telecom) project, a German-Canadian collaborative effort funded by the German Federal Ministry of Education and Research and the National Research Council of Canada
Abstract: Photonic power converters (PPCs), which convert narrow-band light to electricity, are essential components in power-by-light systems. When designed for telecommunications wavelengths such as the O-band, near 1310 nm, the devices are well-suited to power-over-fiber applications. Despite the potential for very high power conversion efficiencies ( >50% ), PPCs can be adversely affected by high-intensity nonuniform illumination conditions. In this work, we characterized two O-band PPC designs based on: high-quality InGaAsP absorber material lattice-matched to an InP substrate, and metamorphic InGaAs absorber material lattice-mismatched to a GaAs substrate, a more cost-effective and scalable alternative. We measured each device under O-band laser illumination with five beam profiles having peak-to-average ratios ranging from 2 to 11. Both devices were insensitive to the beam uniformity for input illumination with average irradiance below 2 W/cm2 over their 5.4-mm2 active areas, but exhibited better open-circuit voltages under larger, more uniform illumination profiles at higher incident powers. Measured efficiencies reached 52.8% and 48.7% for the lattice-matched and mismatched devices, respectively. Distributed circuit modeling results suggested that both lateral conduction losses and localized heating effects were responsible for the measured dependence on beam-size. Our work demonstrates the potential for O-band PPCs, presenting two highly efficient designs suitable for powering devices requiring ≲250 mW, with an appropriate illumination profile.
Click here for the full article.
M. N. Beattie, H. Helmers, G. P. Forcade, C. E. Valdivia, O. Höhn, and K. Hinzer, InP- and GaAs-based photonic power converters under O-band laser illumination: Performance analysis and comparison, IEEE J. Photovolt. (2022). DOI: 10.1109/JPHOTOV.2022.3218938
SUNLAB research associate wins 3rd place at TiE Ottawa PitchFest
Congratulations to SUNLAB research associate Kibby Pollak on winning 3rd place at the TiE Ottawa PitchFest 2022 held as part of TieCon Canada 2022, October 27 and 28, 2022. Kibby is the founder of MyPITBOARD, an on-board real-time feedback system for motocross racing. Twenty-two companies were competing as part of TiE Ottawa PitchFest 2022. The top five companies qualified for the finals which consisted in a seven-minute presentation judged by Canada's most active investors in front of approximately 150 people. MyPITBOARD received 3rd place. Congratulations Kibby!
New Publication from the SUNLAB: Applied Physics Letters
Congratulations to SUNLAB researchers, including lead author PhD candidate Gavin Forcade, and their collaborators at Princeton University and École polytechnique de Montréal, on their newest publication which was selected as Featured in Applied Physics Letters.
Waste heat is a free and abundant energy source, with 15% of global total energy use existing as waste heat above 600 K. For 600–900K temperature range, near-field thermophotovoltaics (NFTPVs) are theorized to be the most effective technology to recycle waste heat into electrical power. However, to date, experimental efficiencies have not exceeded 1.5%.
In this new work, researchers optimized the efficiency of three modeled InAs/InAsSbP-based room-temperature NFTPV devices positioned 0.1 µm from a 750 K p-doped Si radiator. They coupled a one-dimensional fluctuational electrodynamics model for the near field optics to a two-dimensional drift-diffusion model, which they validated by reproducing measured dark current–voltage curves of two previously published InAs and InAsSbP devices. The optimized devices showed four to six times higher above-bandgap energy transfer compared to the blackbody radiative limit, yielding enhanced power density, while simultaneously lowering parasitic sub-bandgap energy transfer by factors of 0.68–0.85. Substituting InAs front- and back-surface field layers with InAsSbP show 1.5- and 1.4-times higher efficiency and power output, respectively, from lowered parasitic diffusion currents. Of their three optimized designs, the best performing device has a double heterostructure with an n–i–p doping order from front to back. For radiator-thermophotovoltaic gaps of 0.01–10 µm and radiators within 600–900 K, this device has a maximum efficiency of 14.2% and a maximum power output of 1.55 W/cm2, both at 900 K. Within 600–900 K, the efficiency is always higher with near- vs far-field illumination; the team calculated up to 3.7- and 107-times higher efficiency and power output, respectively, using near-field heat transfer.
Click here for the full article.
G. P. Forcade, C. E. Valdivia, S. Molesky, S. Lu, A. W. Rodriguez, J. J. Krich, R. St-Gelais, and K. Hinzer, Efficiency-optimized near-field thermophotovoltaics using InAs and InAsSbP, Appl. Phys. Lett. 121(193903) (2022). DOI: 10.1063/5.0116806
NSERC CREATE TOP-SET Summer School at uOttawa
The NSERC CREATE TOP-SET program held its summer school at the University of Ottawa from July 18 to 20, 2022. A total of 51 participants hailing from academia, government laboratories and industry took part in the three-day program on the theme of "Getting together towards net-zero solutions". Guest speakers from Canada and the United States discussed subjects relevant to TOP-SET trainees including photovoltaic technologies, policy, entrepreneurship and strategic thinking.
Awards were given to the best student poster and oral presentations. Ms. Paramita Bhattacharyya won first place in the oral presentation competition for her talk on “Design and fabrication of color-generating nitride based thin-film optical filters for photovoltaic applications”. Ms. Bhattacharyya is a PhD candidate in engineering physics under the supervision of Dr. Rafael Kleiman at McMaster University. Mr. Nick Anderson won the best poster presentation award. He is a MASc candidate in electrical engineering under the supervision of Dr. Henry Schriemer at the University of Ottawa. He presented a poster entitled "Probabilistic assessment of narrowband vs broadband solar irradiance temporal variability in Ottawa". Congratulations to all!
uOttawa Institute for Science, Society and Policy Blog Post from SUNLAB Postdoctoral Fellow
As part of a collaboration between the SUNLAB and the University of Ottawa Institute for Science, Society and Policy, SUNLAB postdoctoral fellow Meghan Beattie recently published a blog post exploring how scientists and engineers can help to build public support on Canada's path to net zero by sharing their expertise. In her post, Dr. Beattie describes the energy information landscape, outlines current challenges with public confidence in expert opinion, and identifies pathways for the science and engineering community to address the need for reliable and accessible information to reach public authorities and the public at large.
Click here to read her post.
M. Beattie, How scientists & engineers can share Information to help build public support on Canada’s path to net zero emissions, University of Ottawa Institute for Science, Society and Policy Blog (2022). https://issp.uottawa.ca/en/news/how-scientists-engineers-can-share-information-help-build-public-support-canadas-path-net-zero. (Retrieved July 21, 2022)
New Publication from the SUNLAB: IEEE Journal of Photovoltaics
SUNLAB has published a new paper in IEEE Journal of Photovoltaics, first-authored by PhD candidate Annie Russell. This paper details a multi-year project developing a software platform called DUET (Dual-sided Energy Tracer), which calculates performance of photovoltaic modules and systems under a wide range of geometrical, electrical, and environmental conditions to incorporate detailed irradiance profiles resulting in highly accurate energy yields and other performance metrics.
Abstract: Bifacial photovoltaic (PV) performance models strive to accurately quantify rear-incident irradiance. While ray tracing models are optically rigorous, they require significant computational resources; faster view factor (VF) models are widely adopted but require user-defined loss factors to approximate rear shading and irradiance nonuniformity, introducing uncertainty in energy yield predictions. This article describes DUET—a bifacial PV performance model that calculates optical and electrical performance based on a physically representative array geometry. DUET's novel shading algorithm pairs a 3-D VF model with deterministic ray-object intersections to capture 2-D shade-inclusive irradiance profiles while minimizing computational cost. Series and parallel combination of current–voltage curves capture irradiance nonuniformity throughout the module and array. This article provides validation against open-access system measurements from a test site in Roskilde, Denmark, and comparison to other software tested there. DUET's modeled bifacial energy yield agrees with measured data within −1.56% for fixed-tilt and −0.65% for horizontal single-axis tracked (HSAT) systems. Mean absolute error (MAE) in hourly bifacial power is 14.2–15.0 mW/Wp for fixed-tilt and 17.3–18.3 mW/Wp for HSAT, depending on the module temperature model applied. Comparing modeled and measured rear irradiance of two rear-facing pyranometers, DUET's MAE values of 2.8 W/m2 for fixed-tilt and 3.7 W/m2 for HSAT are among the lowest errors reported for other software tested at this site. DUET provides computationally efficient bifacial performance modeling with geographic, temporal, and structural specificity to determine loss factors for use in other performance models or to be used directly in system design optimization.
Click here for the full article.
A. C. J. Russell, C. E. Valdivia, C. Bohémier, J. E. Haysom, and K. Hinzer, DUET: A novel energy yield model with 3-D shading for bifacial photovoltaic systems, IEEE J. Photovolt. (2022). DOI: 10.1109/JPHOTOV.2022.3185546
SUNLAB at the CanREA Operations Summit
PhD candidate Annie Russell was invited to give a presentation on bifacial photovoltaics modules and systems at the CanREA Operations Summit, which took place in Toronto May 31 and June 1, 2022. See her presentation below.