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Over 86,000 terawatts of solar energy reach the Earth’s surface each year- enough to satisfy current global energy demand 1000 times over.  In 2008, solar electric power amounted to a mere 0.2% of global energy produced but it is at a tipping point with a growth rate of 40% per year. Exponential growth, enormous solar resources and the global economy's unquenchable demand for electricity increasingly position photovoltaic power as vital to 21st century technology.

In this rapidly changing industry, the Solar Power Lab stands-out as having some of the most experienced researchers in the field.  This, coupled with state-of-the-art facilities and institutional support, gives SPL the solid foundation necessary to push the boundaries of what has become a $20 billion sector of the economy.

Arizona State University’s Solar Power Lab serves a staging ground for the new technologies and ideas that will move us forward in our quest for a more sustainable society. 

The Solar Power Lab is also committed to education.  Check out our electronic book for information on photovoltaics, solar industry, and the physics that govern them.  

The Solar Power Lab has numerous capabilities such as:

  • A full pilot line for 6 inch solar cells with an average efficiency of 18.5% for diffused cells
  • New 6 inch solar cell line doe 22%+ heterojunction cells.
  • Extensive capabilities for silicon solar cell characterization
  • Molecular Beam epitaxy system for nano-structured solar cells

News


Photovoltaic Module Efficiencies

A new publication in collaboration with ASU tracks the progress in photovoltaic module efficiency. Previously, efficiency has focused on the smaller solar cell but a practical product requires combing the solar cells into a larger module. The publication includes the most recent photovoltaic module records as well as the historical context by tracking performance sinc 1990. Following the evolution of these efficiencies enables researchers to track the progress of various technologies. The paper we analyzes champion module efficiencies and compares them to champion cell efficiencies to better understand technology trends over the last three decades. Recommendations are provided on how to change the data collection and reporting for champion efficiencies to increase the value of these records.

The publication was a collaboration amoung leading photovoltaic researchers in government, academia and industry. The full reference is: S. Kurtz, I. Repins, W. K. Metzger, P. J. Verlinden, S. Huang, S. Bowden, I. Tappan, K. Emery, L. L. Kazmerski, and D. Levi, “Historical Analysis of Champion Photovoltaic Module Efficiencies,” IEEE Journal of Photovoltaics, vol. PP, no. 99, pp. 1–10, 2018. DOI: 10.1109/JPHOTOV.2018.2794387

Download an early version of the publication

Photovoltaic module efficiency records.
Champion module efficiencies (> 200 cm2) by technology. The symbols differentiate modules by technology, as indicated in the legend. The symbol size reflects the module area, as indicated.

 

Solar Electricity

The US Energy Information Agency publishes the amount of electricity each state uses and the amount generated by solar. The plot below shows the fraction of electricity that is generated by solar in states of the US where we have QESST members.  California is an interesting case as the amount of eletricity from solar has grown from a few percent to over 20% in less than 5 years. It is remarkable how quickly solar electricity can ramp up production even in a large high-tech market such as California. 

Fabrication of Solar Cells.

At the Solar Power Lab we fabricate industrially ready solar cells. We have people from all over the country come and learn how to make a solar cell. To speed the learning process we have put together a video showing the process. We are still working on the narration but here is a sneak peak of the video.

Record Open Circuit Voltage for a Silicon Solar Cell


Silicon Solar Cell Voc's

Analysis of the recombination mechanisms of a silicon solar cell with low bandgap-voltage offset was published. http://aip.scitation.org/doi/full/10.1063/1.4984071.

The mathematical dependence of bandgap-voltage offset on Auger and radiative recombination is derived. Open-circuit voltages over 760 mV were measured on 50-μm-thick structures, leading to bandgap-voltage offsets at open-circuit down to 0.35 V. We demonstrate the potential of thin silicon devices to reach high voltages, and bandgap-voltage offsets in line with the best reported for direct bandgap materials such as gallium indium phosphide and gallium arsenide.

Picture and legend: Intrinsic open-circuit voltage (black curve) and intrinsic bandgap offset open-circuit voltage (red curve) as a function of cell thickness, considering the Auger, the radiative recombination mechanisms as well as the Lambertian light-trapping limit. Recent experimental results of high VOC for silicon and the corresponding WOC are shown.

Seminar: Demand Side Management of PV Systems in Rural Areas in Africa

Seminar: Demand Side Management of PV Systems in Rural Areas in Africa

Speaker: Catarina Augusto

May 16, in ERC 189, from 2:00 to 3:00 p.m

Renewable energy systems depend strongly on energy efficiency, impacting directly the power size of the systems, and the investment cost. In developing countries, energy supply is poor and the investment costs are high. In this scenario, energy efficiency is critical to secure proper energy supply, more than in developed economies. Demand Side Management (DSM) can help to answer to this problem. In this work, we study the potential of DSM on renewable energy microgrid systems in remote areas. Fossil fuel and batteries are the two most expensive components in these systems. We analyse the impact of DSM strategies in reducing the needs of fossil fuels and how it could improve the performance of batteries in the microgrids. Different scenarios were design based on the main DSM strategies: conservation, peak clipping, load shifting and valley filling. The study is based on Soroti community, a small town in central-east of Uganda, supplied by a PV-diesel microgrid system. The tools used in this study are LoadProGen (for load profile estimation) and HOMER (for DSM scenarios analyses). The results show that combining all DSM strategies improve the performance of the power systems, and reduce the energy supply costs. The study also demonstrate that the nominal power capacity of the system has a higher impact on the energy cost than the reduction of diesel consumption. In systems with DSM, the LCOE has an improvement of 20%. These results highlight the importance of the often-neglected DSM strategies for isolated microgrids, which have the potential for promoting access to electricity in many regions of the world with clean renewable energies.

Catarina Augusto is a final-year MSc student in Energy and Environmental Engineering at Science Faculty of University of Lisbon (Portugal). Her background is on: renewable energy systems, solar photovoltaic and energy efficiency. She also studied energy systems in Utrecht University (Netherlands). In last year, she developed comprehensive work on Demand Side Management of energy systems getting proficient in two tools: LoadProGen and HOMER. LoadProGen is a mathematical algorithm in Matlab created by the UNESCO chair Group in Energy for Sustainable Development of Politecnico di Milano that estimates daily load profiles of un-electrified communities in rural areas. HOMER is a software developed by NREL that optimizes the design of microgrid systems.

QESST at the Aprende Science Fair

At the science fair for the local middle school QESST put on a display on solar and fun to be had with liquid nitrogen. The temperature reading on the liquid nitrogen wa -309 °F. Arizona normally doesn't normally get that cold!. The display was to complement the excellent work done by the Aprende middle school student for their science fair project. Thanks very much to SPL students Max, Alex and Mark for making the night such a success.

 

Cover Story of the latest Journal of Engineering Education

We made the cover story of the latest edition of the Journal of Engineering Education (JEE). Katherine Nelson's PhD work on "Students’ Misconceptions about Semiconductors and Use of Knowledge in Simulations" was featured as the cover story on the April 2017 edition of the Journal of Engineering Education. Solar Cells are based on the principles of semiconductor device physics. Dr Nelson and her co-authors used the instructional materials at the pveducation.org website to explore how student's misconceptions are either reinforced or overcome by the animations. Her findings will enable instructors to create better simulations to aid student learning.

The full paper is at: http://onlinelibrary.wiley.com/doi/10.1002/jee.20163/full

Background

Little research exists on students’ misconceptions about semiconductors, why they form, and what role educational resources like simulations play in misconception formation. Research on misconceptions can help enhance student learning about semiconductors.

Purpose (Hypothesis)

This project sought to identify students’ misconceptions about three semiconductor phenomena – diffusion, drift, and excitation – and to determine if prior knowledge, knowledge acquired from watching animated simulations, or both were related to students’ misconceptions. We hypothesized that students would hold misconceptions about those phenomena and that students’ prior knowledge and knowledge acquired from watching animated simulations would be associated with their misconceptions.

Design/Method

Forty-one engineering students completed an instrument that asked questions about three semiconductor phenomena after the students had observed the animated simulations. Responses were analyzed and coded using two frameworks: misconception and knowledge use.

Results

Misconceptions were prevalent for all three phenomena. Misconceptions were associated with use of incorrect prior knowledge, a combination of correct or incorrect prior knowledge, and the knowledge acquired from watching the animated simulations alone or in combination with correct and incorrect prior knowledge. Misconceptions indicated a lack of understanding of chemistry and physics concepts.

Conclusions

Findings indicate that students hold many misconceptions about semiconductor phenomena. These misconceptions were common among our participants. The knowledge acquired from the animated simulations alone or in combination with prior knowledge could reinforce or contribute to misconception formation. Our findings can guide instructors to use or create better simulations to aid student learning.

 

Photovoltaics now 1.8 % of the world's electricity

The latest report from the International Energy Agence (IEA) shows that photovoltaics supplies 1.8% of the world's electricity consumed. Photovoltaics (PV) grows exponentially while electricity demand grows slowly so it was only two years ago that photovoltaics supplied less than 1% of the world's electrcity. At current growth rates photovoltaics will suppply all the world's electcity in 2030. A more likely scenario is that the declining costs of photovoltaics will enable access for the 1.1 billion people without electrcity, and new technologies such as electric cars.

 

Solar research facility on Tempe campus poised for big developments

Federal officials tour ASU's photovoltaics lab, the nation's largest

https://asunow.asu.edu/20170424-solutions-federal-officials-tour-asus-ph...

New Solar Cell Tester

ASU took delivery of a new advanced solar cell efficiency tester from Sinton Instruments this week. The new tester is a FCT-450 and is an upgrade of our previous tester also from Sinton Instruments. A significant advantage of the new system is the ability to measure smaller area cells, a broader range of temperature measurements and the extraction of substrate doping from the completed solar cell.

 

Like the previous model, the new tester is capable of autmoated SunsVoc and LightIV measurements giving unambigous extraction of cell series resistance and shunt resistance. The tester uses a voltage modulation technique to neutralize the capacitive effects in high performance solar cells. With our record voltages we experience decay lifetimes of 2 ms in the completed cells. Most testers have problems with our cells as the sweep rate is a similar order of magnitude. We have found that the voltages from the FCT  match those measured at NREL even for cells where the voltage approaches 750 mV.