Highlight all of ASU's renewable energy research.

Postcards from the ledge

Hoover Dam excursion for Pakistani scholars bridges knowledge, culture

May 4, 2017

A group of 27 Pakistani engineering scholars from the U.S.-Pakistan Centers for Advanced Energy, better known as USPCAS-E, set off on an adventure over spring break, learning what nature can engineer, what people can engineer and the power their imagination has to inspire innovation.

An $18 million United States Agency for International Development grant supports the project with Arizona State University as the hub for the energy component of the project in partnership with the National University of Science and Technology — Islamabad (NUST), the University of Engineering and Technology in Peshawar and Oregon State University. “Big dams in Pakistan are normally earth and rock fill dams, so there is a need to build concrete arc dams like Hoover Dam in Pakistan that are more impressive, efficient and modern,“  says Muhammad Ahsan Amjed, NUST. Photo courtesy of Muhammad Ahsan Amje “Big dams in Pakistan are normally earth and rock fill dams, so there is a need to build concrete arc dams like Hoover Dam in Pakistan that are more impressive, efficient and modern,“ say Muhammad Ahsan Amjed, National University of Science and Technology. Photo courtesy of Muhammad Ahsan Amjed Download Full Image

The scholars are part of the third cohort to visit the United States in order to study renewable energy at ASU’s Ira A. Fulton Schools of Engineering as part of a larger effort to boost development of solutions for Pakistan’s growing energy needs. Spring break offered a respite from their classes and lab work, and provided a chance to see engineering in action.

The scholars kicked off their journey by visiting one of nature’s greatest engineering wonders, the Grand Canyon. The canyon stood as a compelling example of the power found in nature, as seen by the river carving away at the landscape for millennia. The challenge for the scholars was to learn from nature and learn how to harness that energy.

Their next stop at Hoover Dam illustrated just that. The scholars saw first hand how the Colorado River was used as a source of renewable hydroelectric power through ingenuous civil engineering.

USPCAS-E Scholars, Left to right: Farah Akram, Anam Zahra, Maham Akhlaq, Atoofa Zainab, Photographer: Erika Gronek/ASU

“The sheer brilliance that the engineers displayed in [their] era with such a megastructure was a rarity, [and] is a sight to behold. It solved the water distribution problems for seven different states,” said Haider Saif Agha from NUST.

Learning about this pinnacle of clean energy was key for the scholars because many of them are studying photovoltaic, wind and hydroelectric energy options. The USPCAS-E project set out to explore renewable energy as a means for resolving the energy crisis happening in Pakistan today, leaving the country with rolling blackouts that last 6–16 hours a day.

The dam was created for the purposes of flood control, irrigation and power production, all of which are applicable to Pakistan’s needs.

“I see a comparison with Pakistan’s Kalabagh Dam,” said Asfand Yar Ali, of the University of Engineering and Technology, Peshawar. Kalabagh Dam is proposed dam that could help Pakistan with flood control. “We are facing minor and major floods every year in [the] monsoon [season]. Similarly, the dam will help Pakistan rejuvenate its agriculture and overcome [the] energy crisis.“

Hoover Dam was an example of what could be implemented back home for the scholars.

“I learned that we can solve all of our country’s energy problems by just mixing innovation and engineering in the right proportions,” said Usman Salahuddin of NUST.

To shake things up, the scholars next visited the California Science Center. Atoofa Zainab of NUST had a personal favorite there – the earthquake simulator.

“I learned about the how certain buildings are made in case of an earthquake. The lesson that I learned is that Pakistan is in dire need of these types of services and technologies.”

Inspiring the heart and the exchange of culture

Inside Hoover Dam. Photo credit: Usama Khalid, NUST/ASU.

Though engineering is the primary point of USPCAS-E, other aspects of the initiative like promoting gender equality and engaging in cultural exchange are key aspects as well. The scholars expressed heartfelt thanks to be a part of a program that educates not just their inner engineer, but also cements their role as a global citizen.

“I have honestly no words to define my experience I had on spring break. It was both fun and a learning experience,” said Farah Akram of NUST. “The places we visited showed us a new face of the world. The views of the Grand Canyon, [the] innovative construction of Hoover Dam, fun and virtual reality-based rides of Universal Studios, learning at the California Science Center and [having a] playful time in Santa Monica gave us the most beautiful time of our lives.”

“Something that really impacted my heart was the celebration of diversity in America. America celebrates its diversity, be it in L.A., Tempe, Las Vegas or any other city. I was impacted by views on tolerance, freedom of speech, action,” reflected Haider Saif Agha of NUST.

Muhammad Ahsan Amjed of NUST ruminated that, “if you really want to understand the culture and people of any particular area, you will have to travel across that region in order to better understand their traditions, their peculiarities, cultural idiosyncrasies [and] subtle differences in their way of living. Such excursions help us renew our perspective about our research, our lives and our goals.”

The cultural exchange component of the program provides unlimited opportunity for visitors and Americans to engage with each other, allows visitors to find their place in the global community, breaks down prejudices and misunderstandings, and in the long-term expands and strengthens relationships between the two countries.

Erika Gronek

Communications Specialist, Ira A. Fulton Schools of Engineering

ASU engineer looks to improve next-gen materials for solar cells

April 25, 2017

New findings by an Arizona State University engineer outline new advances in solar cell technology and point to the incredible potential of the material used to fabricate the cell — gallium nitride.

A research paper published April 17 in Applied Physics Letters details electrical engineering Assistant Professor Yuji Zhao’s efforts to use gallium nitride to create a high-performance solar cell capable of operating under extremely high temperatures. Electrical engineering Assistant Professor Yuji Zhao stands in his Metal-Organic Chemical Vapor Deposition lab on the Tempe campus, where he works with gallium nitride, a compound with unique properties. Zhao's research is focused on exploring gallium nitride's use in optoelectronics and high-power and high-frequency devices. Photo by Pete Zrioka/ASU Download Full Image

Gallium nitride is a unique compound, the properties of which make it an excellent candidate for use in optoelectronics and high-power and high-frequency devices.

“This material is remarkable and has such high potential,” Zhao said.

Zhao notes that some have called gallium nitride the next silicon — the ubiquitous material that serves as an integral component of many of our electronics, from computer chips and solar cells to transistors and integrated circuits. Gallium nitride could prove to be superior to silicon, and Zhao’s work is paving the way toward faster, more efficient and higher-powered devices of all kinds.

Zhao first began working with the material under pioneering researcher Shuji Nakamura of the University of California, Santa Barbara. Nakamura was awarded the Nobel Prize in Physics in 2014 for developing efficient blue-light-emitting diodes, which has enabled bright and energy-saving white-light LEDs.

While working toward his doctorate, Zhao focused on employing gallium nitride for use in LEDs and lasers. Now he’s taken the material far beyond optoelectronics, expanding its use for solar panels, power systems and more. His exploration of the material’s myriad uses has earned him support from both NASA and the U.S. Department of Defense.

In 2015, Zhao was awarded a prestigious Early Career Faculty Space Tech Research Grant from NASA, a first for Fulton Schools faculty. The award supported the focus of his Applied Physics paper to create high-temperature resistant solar cells.

“They have high hopes for this project. They seem to believe this is one of the most promising methods to achieve their goals,” Zhao said.

Currently, Zhao is prototyping the solar panels, and will begin thermal testing soon.

“It’s not a question of whether or not the panels will work under high temperatures, but of how efficiently they will perform,” Zhao said.

More recently, he received a $300,000 award from the DOD’s Defense Threat Reduction Agency, which supports basic research to counter weapons of mass destruction. Zhao’s work with the DTRA is focused on using aluminum nitride to create transistors that can withstand high voltage and resist radiation damage.

To test this, he and his team will construct a Schottky Diode — a basic two-terminal electric component — and place it in a radioactive environment, subjecting it to different types of radiation in varying doses and rates of exposure. This radioactive stress test will eventually cause degradation in performance in the diode. That’s when Zhao will turn to materials studies to determine how to improve the material’s resistance and performance.

The applications are far reaching, such as for more robust power electronics and communications systems, but the DTRA is primarily interested in military devices that would remain operational following a radiation event, Zhao said.

Zhao credits his success in attracting funding to refine materials and explore their uses to the work being done in his cutting-edge Metal-Organic Chemical Vapor Deposition lab on the Tempe campus.

“One of the key reasons I was awarded these grants was first my background with this work, but also the capability of the MOCVD lab,” Zhao said. “The equipment we use is industry standard, not different from what you’d find in a major company.”

The lab required an estimated investment of $800,000 to set up and became fully operational in fall 2016.

He envisions the lab as a truly interdisciplinary space, and not only because his research draws on the expertise of physicists, materials scientists and device designers. Zhao wants the MOCVD lab to be an unparalleled resource for all of the Fulton Schools.

His ultimate goal mirrors the Nobel Prize description: developing science and tech for the betterment of humanity. He’s chosen refining and improving next-generation materials, such as gallium nitride, as his avenue to do so.

“The idea is to benefit as much of ASU as possible, which will hopefully extend outside of the university as well,” Zhao said.

Pete Zrioka

Managing editor, Knowledge Enterprise


image title

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

ASU boasts nation's largest photovoltaic research facility, key to solar power.
ASU expert says a trillion dollars will be invested into solar in next 20 years.
April 24, 2017

Solar research facility on Tempe campus poised for big developments

Federal representatives are visiting Arizona State University’s powerhouse photovoltaics lab this week to review progress made in research on the energy of the future.

ASU’s Quantum Energy and Sustainable Solar Technologies Engineering Research Center is the largest photovoltaic research facility in the country, and the only one funded by the National Science Foundation and the Department of Energy.

In the past year, more solar has been installed than any other source of electricity. Photovoltaic installations were up 95 percent in 2016. There are more jobs in solar than exist in oil or gas extraction. It’s a power source supported by all sides of the political spectrum.

Society’s advancement is tied to the amount of energy it can harness, center director Christiana Honsberg said. Right now, compared with automotive technology, solar cells are at a Ford Model T level.

Solar is at a tipping point, Honsberg said. In the next 20 years, about a trillion dollars will be invested.

“In a lot of ways, the goal is to define a path that helps that trillion-dollar industry become more sustainable and addresses a lot of the critical issues,” she said.

The center identifies technical barriers to sustained improvement — high efficiency, scalability and sustainability — and tackles them by breaking down research barriers.

“Our central defining feature is that you can continue to improve both the cost of solar at the same time you improve its performance,” Honsberg said. “You continue to get higher efficiency and lower cost simultaneously. That’s a little bit hard to do. As cars improve, they get more expensive. … Semiconductor technologies get better and cheaper, but most things don’t get better and cheaper.”


 ASU Quantum Energy and Sustainable Solar Technologies Engineering researchers deposit one of many layers while building a solar cell. Photo by Jessica Hochreiter/ASU

 ASU’s center opened in 2010 and has been ramping up every year, adding facilities and faculty. It started with two faculty members and now has seven.

It holds several world records.

“Some of them are true world records, and some are voltage records,” Honsberg said. “The term ‘world record’ is very precisely defined in solar. … The fact that we hold the voltage record in every commercially relevant material is significant in that our physics and ideas are better than anything else out there.”

Engineering Research Centers are the largest awards bestowed by the National Science Foundation. At any given time, there are only 20 ERCs operating in the country. It’s a prestigious and rare award. Only one-quarter of 1 percent of applicants to the program win funding. It’s a 10-year award, given only after five stringent reviews.

ASU has two of them.

“ASU has really ramped up in the ERCs,” Honsberg said. “There aren’t a whole lot of ERCs, given the very, very broad mission that NSF funds in.”

This week’s visit by a 15-member team is one of three funding reviews during the 10-year period of the award. As well as learning what taxpayer dollars are discovering, they’ll get a look inside how ASU operates.

“We are absolutely embedded into ASU’s mission,” Honsberg said. “Every single aspect of what we do fits in directly. One of the key things we want to do is change the standard university picture of people just sitting in a lab producing papers in obscure journals to actually being able to tackle larger problems and make a larger impact.

“If you’re going to do that, the single-faculty, single-lab model is not the right model. … We want to not only make an impact on a big problem, but we’re also working to develop how you optimally combine many different universities, different (principal investigators), how you integrate education in.” 

Top photo: Solar cells — such as this one being examined by researchers at ASU’s Quantum Energy and Sustainable Solar Technologies Engineering Research Center — are poised to become more efficient and cheaper thanks to an influx of investments. Photo by Jessica Hochreiter/ASU

Scott Seckel

Reporter , ASU Now


Young engineers envision an energy-independent Pakistan

April 10, 2017

Improving the energy grid in Pakistan is, without exception, the priority for a cohort of Pakistani graduate scholars studying engineering at Arizona State University this semester.

Participants in the U.S.–Pakistan Centers for Advanced Studies In Energy program, the students recently demonstrated renewable energy concepts during ASU’s Night of the Open Door — an event during which Phoenix-area residents visit campus, meet faculty and students, and explore research projects.  Above: Hira Rehman (in pink) and Asma Shamim (in gold) demonstrate the power of photovoltaics with members of the Tempe community during Night of the Open Door. Photographer Erika Gronek/ASU Above: Hira Rehman (in pink) and Asma Shamim (in gold) demonstrate the power of photovoltaics with members of the Tempe community during Night of the Open Door. Participants in the U.S.–Pakistan Centers for Advanced Studies In Energy program, the students recently demonstrated renewable energy concepts during ASU’s Night of the Open Door – an event during which Phoenix-area residents visit campus, meet faculty and students, and explore research projects. Photo by: Erika Gronek/ASU Download Full Image

Toy solar car races at the USPCAS-E exhibit attracted many young guests, giving the engineering students an opportunity to explain the importance of developing renewable sources of power. They also handed out LED light-up fans that, when they spin, spell out, “Renewable Energy: I’m a big fan.”

USPCAS-E is a partnership between ASU and two leading Pakistani universities: the National University of Science and Technology Islamabad and the University of Engineering and Technology in Peshawar. Funded through the U.S. Agency for International Development, the program is designed to find innovative solutions to Pakistan’s energy challenges. The group of students, comprised of 18 men and 11 women, represents the third cohort to spend a semester at ASU before returning to Pakistan to complete their master's degrees.

Ussama Khalid Barki (left) and Usman Salahuddin (right) explain how photovoltaics could change the energy situation in their home country at Night of the Open Door – Polytechnic. Photographer Erika Gronek/ASU

Ussama Khalid Barki (left) and Usman Salahuddin (right) explain how photovoltaics could change the energy situation in their home country at Night of the Open Door on the Polytechnic campus. Photo by Erika Gronek/ASU

Different backgrounds lead to diverse solutions to common goal

A NUST grad with a bachelor’s degree in telecommunications engineering, Anam Zahara from Southern Punjab is now working on a master’s degree in energy policy, with a focus on electrical engineering, through the program.

“We have many rolling blackouts in my area of the country,” she explained. Her vision is to integrate her telecommunications and electrical engineering education so she can “be a part of the process that improves Pakistan’s energy infrastructure.”

Education is a priority in Zahara’s family – both parents are teachers, two sisters are medical doctors and another has a master’s degree in agriculture. 

“One thing I’ve learned here is that time is money,” she said. “It’s important to be punctual for class.”

For Usman Salahuddin from Karachi, the decision to pursue an advanced degree in energy systems was born of frustration. With a bachelor’s degree in chemical engineering from NUST, Salahuddin found himself literally powerless on the job almost daily in the fertilizer industry.

“There was not enough gas to feed the furnace, so we’d have to shut down the factory,” he explained. “It taught me that we cannot rely on fossil fuels. We must develop renewable technologies that can be safely implemented for industry.” 

His attraction to the USPCAS-E program was heightened by the opportunity to focus on entrepreneurship. “This program not only makes us researchers, it also emphasizes becoming entrepreneurs,” Salahuddin said. “I believe small start-up companies will contribute significantly to solving my country’s energy problems.”

“Physics is about making theories,” said Ussama Khalid Barki, who holds a physics degree from NUST. “Engineering is about execution.” Noting that his country is struggling, Barki said it’s time for action, not theories.

Barki is now pursuing a master’s degree in energy systems engineering with an interest in developing technologies for rechargeable, solar powered batteries, but said he is inspired by energy researchers at ASU. He says he would like to continue conferring with ASU faculty once he returns home and work toward his doctorate.

“I have a new perspective,” he said. “Scientists explore space, but engineers build the telescopes.”

Farah Akram, who has a power electronics degree from NUST, did not let her poor sense of direction thwart her aspirations to pursue a master’s degree in electrical power engineering. “The ASU campus is so big that I got completely lost on my first day,” she said, explaining that her campus at NUST was small in comparison. “But everyone was so helpful, and eventually I found my way.”

The majority of Akram’s family is in business and she, who describes herself as “extremely organized,” is the only engineer. “Our family is passionate about education,” she said. “Engineering made the most sense for me.”

Farah Akram explains to members of the public what USAID’s mission is in Pakistan at Tempe Night of the Open Door. Photographer Erika Gronek/ASU

Farah Akram explains to members of the public what USAID’s mission is in Pakistan at Tempe Night of the Open Door. Photo by Erika Gronek/ASU

Cultural exchange

Unanimously, the students declared the Arizona Renaissance Festival their favorite cultural experience to date. They donned crowns along with other festival-goers and enjoyed the jousting knights, circus performers, musicians and the marketplace.

Actually, marketplaces of all sorts are of interest to the students. “We love shopping,” said Zahara, who says she’s particularly enjoyed Arizona Mills and Tempe Marketplace — both accessible via public transportation.

But more important than shopping and festivals are the opportunities to collaborate with other students.

“I feel so welcome — faculty has been extremely supportive,” Akram said. “This has been an unimaginable, new experience.”

“The cultural exchange has helped me learn how to socialize with people who are different,” says Barki. “One day on a trip via the light rail, a group of elderly ladies got on — so we stood up and gave them our seats. Everyone clapped. It was definitely a notable moment.”

Salahuddin noteed that the learning exchange extends well beyond American customs and culture. “We are not just meeting American students — there are students from five different countries working on one of my lab projects,” he said. “Exposure to these new, wide-ranging perspectives will be incorporated into the problem-solving processes we use when we return home.”

Terry Grant

Media Relations Officer, Media Relations and Strategic Communications


ASU solar, sustainability scholar sojourns to Sweden

March 21, 2017

Though Arizona State University is committed to sustainability and renewable energy, weaning our civilization off fossil fuels and combating our changing climate is a much larger issue than the university can tackle on its own. Creating a truly sustainable world will take a global collaboration from researchers.

Electrical engineering Professor Meng Tao is one such researcher. He'll take his solar energy expertise to collaborate with Swedish researchers as the 2017 Fulbright Distinguished Chair in Alternative Energy Technology. As part of this $125,000 estimated package that includes a monthly allowance, housing assistance and airfare, Tao will work at the Chalmers University of Technology in Gothenburg, Sweden, for the 2017–2018 academic year. Portrait of Meng Tao Electrical engineering Professor Meng Tao has been awarded the 2017 Fulbright Distinguished Chair in Alternative Energy Technology, which will take him to Sweden's Chalmers University of Technology over the 2017–2018 academic year to study solar-powered charging for electric vehicles and solar module recycling. Photo courtesy of Meng Tao Download Full Image

“I hope to exchange ideas with my Swedish colleagues, to learn from one another, to stimulate new ideas and to facilitate long-term collaborations on some of the most pressing energy issues we are facing,” Tao said.

Tao is one of 45 Fulbright Distinguished Chairs awarded in 2017 to top scholars with exemplary teaching and publication records, many of whom are in the social sciences. The position is considered one of the most prestigious Fulbright Scholar Program appointments.

Douglas Cochran, who served as 2015 Fulbright Distinguished Chair in Science and Technology at the Australian Department of Defence’s Defence Science and Technology Group, said Tao’s appointment reflects favorably on ASU and the Ira A. Fulton Schools of Engineering.

“The Fulbright Distinguished Chair in Sweden will provide Professor Tao with an excellent platform for building a new base of international collaborators, affecting not only his own scholarly and educational activities but potentially extending to enduring ties between his broader circle of ASU and U.S. colleagues and their counterparts in Europe,” said Cochran, a fellow faculty member in the School of Electrical, Computer and Energy Engineering, one of the six Fulton Schools.

Tao’s research during his Fulbright Distinguished Chair appointment focuses on two areas: charging electric vehicles with solar energy and making solar modules more sustainable through value-added recycling.

Since the electric grid is largely powered by fossil fuels, Tao said electric cars lose their environmental benefit if they’re charged through the grid, but solar may hold the answer to this problem.

“Charging electric vehicles by solar electricity makes environmental sense, but it is still expensive and unreliable,” he said. “That’s why we are developing a new solar photovoltaic system for charging electric vehicles that reduces the cost of solar electricity by 30 percent while eliminating its intermittency.”

With the potential for more solar photovoltaic systems in place for charging electric vehicles and other uses, Tao hopes to make paying for photovoltaic module recycling more attractive.

“There are valuable and bulky materials in silicon solar modules such as solar-grade silicon, silver, aluminum and glass,” Tao said. “When properly recovered, they can generate enough revenue to allow a profitable recycling business without any subsidies. We are developing a technology to do just that.”

Tao, who is also a senior sustainability scientist at ASU’s Julie Ann Wrigley Global Institute of Sustainability, is looking forward to connecting the work done at ASU with that of Chalmers University of Technology.

“There is a wide range of research projects going on within the Fulton Schools and within ASU in the domain of energy, environment and sustainability,” Tao said. “I hope to be able to serve as a bridge and connect faculty and students of similar interests on two campuses for a broader collaboration across the Atlantic Ocean.”

For one week during Tao’s stay, one of his students will visit to help introduce the Fulton Schools’ work in these areas.

Sweden’s Chalmers University of Technology is an excellent fit for Tao’s Fulbright research proposal, especially the Swedish Electromobility Centre, a national Center of Excellence for hybrid and electric vehicle technology and charging infrastructure, and the Chalmers Competence Centre Recycling.

“The Swedish Electromobility Centre involves experts from all over Sweden and serves as a base for interaction between academia, industry and society. As an added bonus, major automaker Volvo is headquartered nearby,” he said. “The goal of the Chalmers Competence Centre Recycling is to be a network and catalyst for multidisciplinary R&D collaboration within the field of circular use of materials. Recycling is critical for a resource-efficient society.”

He hopes to spread knowledge of solar technology scalability and sustainability issues beyond Sweden to other European Union countries as well.

Beyond the engineering issues, he’s looking forward to learning about his new host country.

“I hope to learn a bit about the culture, history, geography and people of Sweden,” Tao said. “I hope to renew old relations, build new relations and make friends from all walks of life: college students, faculty members and average Joes in my neighborhood.”

He also finds it interesting to be a representative of the United States in a new country.

“As a first-generation immigrant, I was surprised when I received the notification,” he said. “I will represent, unofficially, the United States in a country that is neither my birth country nor my adoptive country. How fascinating this experience will be.”

First things first, Tao said, is getting ready for the Swedish climate.

“My wife and I are struggling to find suitable attire for the 2017 Nobel Award Ceremony and the long, cold winter in Sweden,” he says. “Phoenix is definitely not the best place for winter clothes.”

Monique Clement

Communications specialist, Ira A. Fulton Schools of Engineering


UNAM team joins ASU power ‘boot camp’

March 10, 2017

The term “microgrid” may not conjure excitement in the average person, but for organizations or people that stand to lose money, life, limb or living standards due to power outages, it does.

Microgrids can keep the lights on even after main power sources fail and they were the focus of a week-long “boot camp” held at Arizona State University’s Polytechnic campus this week for military veteran students and an academic trio from Mexico City.   people working with solar panel UNAM doctoral students Fernanda Alvarez and Jose Fuentes, center (left to right), examine part of a microgrid solar-powered system alongside student veterans at Arizona State University’s Polytechnic campus, Wednesday, March 8, 2017, during the Microgrid Boot Camp. Photo by Peter Zrioka/ASU Download Full Image

Two doctoral students and a professor from the Universidad Nacional Autónoma de México (UNAM) joined the event organized by the Ira A. Fulton Schools of Engineering and part of the U.S. Navy’s NEPTUNE energy research project with ASU.  

“The microgrid boot camp is a 40-hour intensive, all-inclusive approach to microgrid education focusing on infrastructure basics,” said Nathan Johnson, assistant professor for the Fulton Schools at the Polytechnic campus and director of the Laboratory for Energy and Power Solutions. “This week and the involvement of UNAM is one example of how we’re taking our research and training to be a true global program. We’re on the early stages of developing global microgrid centers of excellence.”

NEPTUNE is an energy research project established with Department of Defense funding to break new ground in alternative energy while employing student veterans to assist and gain marketable skills. Veterans and other military-affiliated students are the primary audience but Johnson saw the benefit in having UNAM participate and continue the existing collaboration.

“For them to come up was more of a good opportunity,” Johnson said. “Given that UNAM and ASU have an exchange, this is part of their exchange to come work with us from an educational research standpoint. The work we’re doing with Cesár Angeles [UNAM lead professor], focuses on the problem of significant amount of solar on the grid. How do you effectively manage those with storage and advanced controls.”

Johnson said that part of the goal in partnering with UNAM is to develop energy simulations, hardware and then connecting them to “control the dial” and make sure it meets utilities’ safety and reliability requirements for one grid, and then for multiple ones connected together.  

The objective of using microgrids is to provide quality, reliable stand-alone energy during a loss of power from the main grid — i.e., the main electric power infrastructure. Microgrid systems, which can be powered by solar or other energy, are being installed in hospitals, military bases, college campuses and have become very common in data centers, Johnson said.  They can also be packaged and transported where needed during disaster response.

“So places that need to have 100 percent reliable power,” Johnson said. “They go down for seconds and it’s millions of dollars.  For many of the small businesses and household consumers, the focus is on renewable energy and reduced electric bills.”

The boot camp included interactive tours, lessons, lectures and talks from corporate and other ASU partners.  More importantly it enabled the exchange of perspectives and capabilities, a valuable aspect to the UNAM students.

“I’ve worked with photovoltaic systems, I’ve utilized these inverters, and utilized practically the same brand of panels, so it’s something that we know,” said UNAM doctoral electrical engineering student Jose Fuentes, about being familiar with some of the boot camp concepts and equipment. “What is interesting here is how easily the systems can be built and integrated quickly with the support needed to assemble everything and have it running within a semester or so.”

Another key aspect of the course is the focus on renewable energy, said Fernanda Alvarez, also a doctoral electrical engineering student at UNAM and a Colombia native. 

“There are many parts in Mexico, Colombia, here and other places where due to distance or location, there isn’t quality access to energy,” Alvarez said. “Systems like these will obviously make life easier and give everyone the rightful access to electricity and quality of life.”

The Micogrid Boot Camp is one of six NEPTUNE projects at ASU. The acronym stands for Naval Enterprise Partnership Teaming with Universities for National Excellence. Locally, the program is a collaboration between ASU LightWorks, the Ira A. Fulton Schools of Engineering and the Pat Tillman Veterans Center. 

Jerry Gonzalez

Media Relations Officer, Media Relations and Strategic Communications

image title

ASU, Stanford researchers achieve record-breaking efficiency with tandem solar cell

February 20, 2017

Some pairs are better together than their individual counterparts: peanut butter and chocolate, warm weather and ice cream, and now, in the realm of photovoltaic technology, silicon and perovskite.

As existing solar-energy technologies near their theoretical efficiency limits, researchers are exploring new methods to improve performance — such as stacking two photovoltaic materials in a tandem cell. Collaboration between researchers at Arizona State University and Stanford University has birthed such a cell with record-breaking conversion efficiency — effectively finding the peanut butter to silicon’s chocolate.

The results of their work, published Feb. 17 in Nature Energy, outline the use of perovskite and silicon to create a tandem solar cell capable of converting sunlight to energy with an efficiency of 23.6 percent, just shy of the all-time silicon efficiency record.

“The best silicon solar cell alone has achieved 26.3 percent efficiency,” said Zachary Holman, an assistant professor of electrical engineering at the Ira A. Fulton Schools of Engineering. “Now we’re gunning for 30 percent with these tandem cells, and I think we could be there within two years.”

Silicon solar cells are the backbone of a $30 billion-a-year industry, and this breakthrough shows that there’s room for significant improvement within such devices by finding partner materials to boost efficiency.

The high-performance tandem cell’s layers are each specially tuned to capture different wavelengths of light. The top layer, composed of a perovskite compound, was designed to excel at absorbing visible light. The cell’s silicon base is tuned to capture infrared light.

Perovskite, a cheap, easily manufacturable photovoltaic material, has emerged as a challenger to silicon’s dominance in the solar market. Since its introduction to solar technology in 2009, the efficiency of perovskite solar cells has increased from 3.8 percent to 22.1 percent in early 2016, according to the National Renewable Energy Laboratory.

The perovskite used in the tandem cell came courtesy of Stanford researchers — professor Michael McGehee and doctoral student Kevin Bush, who fabricated the compound and tested the materials.

The research team at ASU provided the silicon base and modeling to determine other material candidates for use in the tandem cell’s supporting layers.

Overcoming challenges with perovskites

Though low-cost and highly efficient, perovskites have been limited by poor stability, degrading at a much faster rate than silicon in hot and humid environments. Additionally, perovskite solar cells have suffered from parasitic absorption, in which light is absorbed by supporting layers in the cell that don’t generate electricity.

“We have improved the stability of the perovskite solar cells in two ways,” said McGehee, a materials science and engineering professor at Stanford’s College of Engineering. “First, we replaced an organic cation with cesium. Second, we protected the perovskite with an impermeable indium tin oxide layer that also functions as an electrode.”

Though McGehee’s compound achieves record stability, perovskites remain delicate materials, making it difficult to employ in tandem solar technology.

“In many solar cells, we put a layer on top that is both transparent and conductive,” said Holman, a faculty member in the School of Electrical, Computer and Energy Engineering. “It's transparent so light can go through and conductive so we can take electrical charges off it.”

This top conductive layer is applied using a process called sputtering deposition, which historically has led to damaged perovskite cells. However, McGehee was able to apply a tin oxide layer with help from chemical engineering professor Stacey Bent and doctoral student Axel Palmstrom of Stanford. The pair developed a thin layer that protects the delicate perovskite from the deposition of the final conductive layer without contributing to parasitic absorption, further boosting the cell’s efficiency.

The deposition of the final conductive layer wasn’t the only engineering challenge posed by integrating perovskites and silicon.

“It was difficult to apply the perovskite itself without compromising the performance of the silicon cell,” said Zhengshan (Jason) Yu, an electrical engineering doctoral student at ASU.

Silicon wafers are placed in a potassium hydroxide solution during fabrication, which creates a rough, jagged surface. This texture, ideal for trapping light and generating more energy, works well for silicon, but perovskite prefers a smooth — and unfortunately reflective — surface for deposition.

Additionally, the perovskite layer of the tandem cell is less than a micron thick, opposed to the 250-micron-thick silicon layer. This means when the thin perovskite layer was deposited, it was applied unevenly, pooling in the rough silicon’s low points and failing to adhere to its peaks.

Yu developed a method to create a planar surface only on the front of the silicon solar cell using a removable, protective layer. This resulted in a smooth surface on one side of the cell, ideal for applying the perovskite, while leaving the backside rough, to trap the weakly absorbed near-infrared light in the silicon.

“With the incorporation of a silicon nanoparticle rear reflector, this infrared-tuned silicon cell becomes an excellent bottom cell for tandems," said Yu.  

Building on previous successes

The success of the tandem cell is built on existing achievements from both teams of researchers. In October 2016, McGehee and post-doctoral scholar Tomas Leijtens fabricated an all-perovskite cell capable of 20.3 percent efficiency. The high-performance cell was achieved in part by creating a perovskite with record stability, marking McGehee’s group as one of the first teams to devote research efforts to fabricating stable perovskite compounds.

Likewise, Holman has considerable experience working with silicon and tandem cells.

“We’ve tried to position our research group as the go-to group in the U.S. for silicon bottom cells for tandems,” said Holman, who has been pursuing additional avenues to create high-efficiency tandem solar cells.

In fact, Holman and Yu published a comment in Nature Energy in September 2016 outlining the projected efficiencies of different cell combinations in tandems.

“People often ask, ‘Given the fundamental laws of physics, what’s the best you can do?’” said Holman. “We’ve asked and answered a different, more useful question: Given two existing materials, if you could put them together, ideally, what would you get?”’

The publication is a sensible guide to designing a tandem solar cell, specifically with silicon as the bottom solar cell, according to Holman.

It calculates what the maximum efficiency would be if you could pair two existing solar cells in a tandem without any performance loss. The guide has proven useful in directing research efforts to pursue the best partner materials for silicon.

“We have eight projects with different universities and organizations, looking at different types of top cells that go on top of silicon,” said Holman. “So far out of all our projects, our perovskite/silicon tandem cell with Stanford is the leader.”

Pete Zrioka

Managing editor , Knowledge Enterprise


Project energizes entrepreneurial aspirations for Pakistani scholars

Partnership between ASU, Pakistani universities aims to produce skilled graduates in the field of energy

December 23, 2016

A second cohort of Pakistani engineering scholars has completed their entrepreneurship course of study at Arizona State University as part of the USPCAS-E program. In addition to entrepreneurship, the students are also studying engineering and policy in an effort to improve their country’s energy prospects.

U.S.-Pakistan Centers for Advanced Studies in Energy is a U.S. Agency for International Development project focused on applied research relevant to Pakistan’s energy needs. The project, which is a partnership between Arizona State University and two leading Pakistani universities, aims to produce skilled graduates in the field of energy. Kenneth Mulligan, professor for the U.S.-Pakistan Centers for Advanced Studies in Energy, presents Pakistani exchange scholar Nafeesa Irshad with her certificate of completion for the entrepreneurship portion of the program. Photographer: Erika Gronek/ASU Kenneth Mulligan, professor for the U.S.-Pakistan Centers for Advanced Studies in Energy, presents Pakistani exchange scholar Nafeesa Irshad with her certificate of completion for the entrepreneurship portion of the program. Photo by Erika Gronek/ASU Download Full Image

ASU entrepreneurship professor Kenneth Mulligan said: “The intention of the program is to improve availability of clean, reliable power in Pakistan. Strategic innovation and entrepreneurship provides a pathway for widespread implementation of their innovative technical solutions. 

“Pakistan is subject to rolling blackouts that impede stability, progress and business. The problems faced in Pakistan are not easy problems, which is why coming up with solutions that reside outside the box are so critical,” said Mulligan, who has taught and mentored both cohorts so far.

“They get to use causative thinking, systems analysis and technical feasibility to solve complex technical problems in energy generation and distribution. However, this problem-solving approach and skillset is insufficient in the development of innovative and disruptive products and technologies.”

students attending energy project class at ASU

Scholars from the U.S.-Pakistan Centers for Advanced Studies in Energy learn about the entrepreneurial mindset at the Ira A. Fulton Schools of Engineering Generator Labs. Photo by Erika Gronek/ASU

Mulligan thinks all of the scholars' final projects have market potential. All 27 of the visiting scholars, six of whom are women, took Mulligan’s class.

One project of particular interest was presented by Nafeesa Irshad. Irshad’s project involved developing a solar-powered drinking water purification system, which addresses both Pakistan’s need for renewable energy and clean water.

“In Pakistan, the unsafe drinking water is the main cause of children’s deaths and other health issues,” Irshad said.

“This system would be reliable to provide safe water to the people through its high temperature and UV C action,” Irshad said.

UV C, a type of ultraviolet light, kills microbes and cleans the water. “It would be [a] more energy-efficient system as compared to existing reverse osmosis technologies.”

Pakistani scholar holding certificate

Kenneth Mulligan, professor for the U.S.-Pakistan Centers for Advanced Studies in Energy, presents Pakistani exchange scholar Noaman Khan with his certificate of completion for the entrepreneurship portion of the program. Photo by Erika Gronek/ASU

Noaman Khan, another enterprising student in the class has the idea to pursue low-cost catalysts for proton exchange membrane (PEM) fuel cells.

He wants to find new materials that can possibly replace platinum as a catalyst because the material is so cost-prohibitive. A more affordable, durable and reliable catalyst would reduce the cost of fuel cells, therefore opening up a market opportunity, according to Khan. Future applications could include the large-scale commercialization of the technology for automotive and other fuel cell applications.

Khan said of the program that it, “is not about publishing research papers but [about] solving Pakistan’s energy problem. It requires science and entrepreneurship to go side by side. I didn't realize it before this course. We should make discoveries that can create value.”

According to Mulligan, “Entrepreneurship gets them to think about implementation and commercial feasibility. It’s a way to connect their engineering skillset with an entrepreneurial mindset. Who has the problem? What is their true pain point? What solution solves both the technical feasibility and commercial feasibility? The benefits are enormous. It equips them to think in terms of real impact on their communities back in Pakistan.”

“My task is to instruct them in lean methodology — the core of tech entrepreneurship — and to inspire and mentor their abilities to solve problems through tech entrepreneurship and commercialization,” Mulligan added.

ASU is leading the U.S.-Pakistan Centers for Advanced Studies in Energy in a collaboration sponsored by the U.S. Agency for International Development and Pakistan’s Higher Education Commission.

An $18 million USAID grant supports the project with ASU as the hub for the energy component of the project in partnership with the National University of Science and Technology – Islamabad and the University of Engineering and Technology in Peshawar and Oregon State University.

The scholars who now see themselves as problem solvers and value creators hope to take their plans back home and turn those ideas into entrepreneurial ventures in Pakistan’s energy sector.

Erika Gronek

Communications Specialist, Ira A. Fulton Schools of Engineering

Manufactured materials offer benefits to energy sector, climate change

December 23, 2016

Mechanical engineer Liping Wang imagines an energy sector enhanced by greater control over thermal radiation. To work toward this objective, he is designing and constructing a host of custom electromagnetic materials.

An assistant professor at Arizona State University, Wang's endeavor is supported by a Young Investigator Program research grant from the Air Force Office of Scientific Research, totaling $360,000 over three years. The program received more than 230 proposals, awarding grants to only 25 percent of applicants. Liping Wang looks over metamaterials created in his Nano-Engineered Thermal Radiation Group. Assistant professor Liping Wang (right) and Hassan Alshehri, a mechanical engineering doctoral student, research manufactured materials as part of Wang's Nano-Engineered Thermal Radiation Group. Photo by Nora Skrodenis/ASU Download Full Image

Thermal radiation refers to the transfer of energy through electromagnetic waves between objects.

Improving thermal radiation and its transport boasts improvements in energy harvesting, as well as thermal management, imaging and sensing — all of which are essential in addressing the world’s urgent need for high-efficiency renewable energy sources and energy-saving materials.

But the quality of thermal radiation, and the energy it generates, is determined by the temperature and properties of the objects, known as emitters and receivers, at play.

Currently, in thermophotovoltaic systems (systems that convert thermal energy to power), efficiency is very low due to the performance of materials that make up the emitters and receivers. These systems commonly suffer from a loss of heat — known as waste heat — rather than using that heat to generate additional electricity.

All of this results in less efficient photovoltaics and is an obstacle in ramping up the usage of solar energy and waste heat, which can be recovered and used as an emission­-free and affordable energy resource.

A solution to the problem lies in designing emitters and receivers made of materials that are near-perfectly efficient in their absorption of sunlight — meaning materials that can selectively control thermal radiation and enhance radiative transport. By extension, this research could help create solar cells that produce more energy, more efficiently.

The game-changing nanoengineered materials that Wang is developing are nanowire-based metamaterials.

These manufactured metamaterials are electromagnetic structures that are deliberately engineered to offer a range of unique electromagnetic properties, which are much more difficult, if not impossible, to achieve in naturally occurring materials or composites, such as rare-earth oxides as wavelength-selective emitters.

“These metamaterials would provide much more flexibility and tunability in materials designed to achieve the best system performance,” said Wang, a faculty member in ASU's Ira A. Fulton Schools of Engineering.

Wang said a significant feature of his metamaterials is their ability to respond to both electrical and magnetic fields at optical frequencies. All lights or electromagnetic waves are made of co-existing electric and magnetic fields, which Wang likens to the “left and right hands of a person.”

“Most natural materials only interact with electrical fields of lights at optical frequencies; in other words, they behave non-magnetically,” said Wang.

During the thermal radiation process, Wang’s nanowire metamaterials can interact with both the electric and magnetic fields, which allows for improved control of light propagation, absorption and emission with “both hands” of the wave.

This control is termed “spectral selectivity,” and can lead to greater energy efficiency and power input by improving the conversion of thermal energy into electricity.

“In addition, the project fundamentally investigates the unexploited radiative thermal transfer process between these unique metamaterials separated by nanometer-scale vacuum gaps,” said Wang, which could further enhance the performance of thermophotovoltaic energy conversion or thermal management.

“We aim to engineer these novel materials for developing high-efficiency renewable energy sources, recuperating waste heat, facilitating thermal managements and mitigating climate change,” said Wang.

About 60 percent of the total energy that is produced in United States is wasted in the form of heat during production, transportation and storage.

“Recycling of such a huge amount of waste heat with highly efficient energy-conversion devices will undoubtedly reduce the amount of fuel consumption and greenhouse gas emission by up to 30 percent,” said Wang. This could alleviate the pressing demand for conventional energy sources and reduce carbon dioxide pollution.

In addition, by funding this research, the Air Force is likely interested in applications to improve optical cloaking and infrared detection.

In his efforts in the Nano-Engineered Thermal Radiation Group, Wang engages a postdoctoral fellow, seven doctoral students including two visiting students from China, and three undergraduates as part of the Fulton Undergraduate Research Initiative.

Rose Gochnour Serago

Communications Program Coordinator, Ira A. Fulton Schools of Engineering

Second cohort of Pakistani students arrives at ASU to brighten country, lives

October 18, 2016

A second group of graduate students from Pakistan recently arrived at Arizona State University to study energy engineering as part of a larger effort to boost development of solutions for Pakistan’s growing energy needs.

ASU is leading the U.S.-Pakistan Centers for Advanced Studies in Energy in a collaboration sponsored by the U.S. Agency for International Development and Pakistan’s Higher Education Commission. Sayfe Kiaei, director of U.S.-Pakistan Centers for Advanced Studies in Energy and a professor of electrical engineering in the Ira A. Fulton Schools of Engineering, welcomes the second cohort of Pakistani exchange students to ASU for the fall semester Sayfe Kiaei, director of U.S.-Pakistan Centers for Advanced Studies in Energy and a professor of electrical engineering in the Ira A. Fulton Schools of Engineering, welcomes the second cohort of Pakistani exchange students to ASU for the fall semester. Photographer: Erika Gronek/ASU Download Full Image

An $18 million grant supports the project — the largest ASU has ever received from USAID.

ASU is coordinating the graduate student exchange program in conjunction with two leading Pakistani engineering universities in an effort to train students to be change agents in helping both countries improve their energy systems.

Support for USPCAS-E is part of $127 million investment by USAID to improve Pakistan’s agriculture and food security as well as access to water and energy.

ASU is the hub for the energy component of the project in partnership with the National University of Science and Technology – Islamabad and the University of Engineering and Technology in Peshawar.

Sayfe Kiaei, director of USPCAS-E and a professor of electrical engineering in the Ira A. Fulton Schools of Engineering believes that ASU is important to the program’s goals because, “The center is a link between ASU’s researchers and international development funding agencies as well as implementers who are working in developing countries worldwide.”

The partnership will further the long history of U.S.-Pakistani relations through the interaction of people, government, industry and academia in order improve energy stability in Pakistan.

Technology and policy

Technology and policy research are key to creating sustainable energy systems that will help enhance Pakistan’s economic potential.

The USPCAS-E program supports Pakistan’s economic development by strengthening the universities involved and by encouraging applied research.

Project topics range from research on battery technologies, photovoltaics and fuel cells to energy policy and energy-efficient buildings.

The range of skills that the exchange students acquire in these areas will help Pakistan meet its energy challenges, while equipping students to succeed in their future engineering careers.

“The students, who are very shy in the beginning, adapt to our laboratory working culture quickly,” said engineering professor Arunachala Kannan, the USPCAS-E technical lead for fuel cell and battery research. “They develop skills in communication, technical and social aspects during their stay working in the multicultural melting pot.”

Addressing the roots of Pakistan’s energy crisis

Pakistan is currently experiencing rolling power-system blackouts that can last up to 16 hours a day.

“Pakistan’s energy system is in crisis” said Clark Miller, director of the Energy Policy Lab at ASU. “To address that crisis requires a new commitment to energy policy, innovation and leadership.”

USPCAS-E is working to prepare young energy leaders to tackle that challenge.

“All of the students in the USPCAS-E programs, in Pakistan and at ASU, are receiving basic training in energy policy to ensure that they can contribute effectively as engineers to the energy policy process,” Miller said. “We are also providing specialized training in energy policy and the social dynamics of energy transitions to a small group of USPCAS-E faculty and students through semester-long programs here at ASU.”

Non-renewable resources like diesel fuel and coal are often imported by Pakistan, while hydroelectric and solar power remain underutilized as research, innovation and implementation in those areas continues to lag in the country. The USPCAS-E project aims to reverse that trend with the help of students in the exchange program.

The human component

Technology and policy are not the only key points of the USPCAS-E initiative. Cultural exchange, soft skills, networking within the industry and bringing disadvantaged students and women to the forefront of the energy field are all important components.

Saqib Sattar, who was a part of the first cohort of Pakistani students to begin studies at ASU in early 2016, spent a great deal of time in the Photovoltaic Reliability Lab. He has some advice for the recent cohort of students.

“Being an exchange student doing research at ASU means that you will be exposed to number of different [types of] equipment in the lab that will help you in learning many new things as well as getting hands-on experience,” Sattar said. “Also you will get the opportunity to meet with people from various cultures and will get to know about them and their culture.”

“So my advice to the current exchange students at ASU is to realize that this is a great opportunity for them not only to develop their technical skills but also soft skills, which are very necessary to be successful in your field, so they should make full use of this once-in-a-lifetime opportunity.”

Hafiz Malik, a student in the new cohorts said he is “loving this tapestry of cultures” at ASU and is looking forward to heeding Sattar’s advice.

The new cohort includes more than twice as many female students compared to previous group of graduate students, bringing the total up to five women.

The group also includes one visiting female faculty member, Rabia Liaquat, who said the total student exchange experience benefits both countries and students economically and culturally, and enhances the professional development of faculty and students alike.

Through the networking opportunities the program provides, Liaquat said, “ASU can help us to interact with other universities for the future, and can connect us with university fellows in our field.”

Andrew Sarracino, the USPCAS-E international visits coordinator, helps to acclimatize the students to life in the United States. He said the female students “are paving the path for more young women in Pakistan so that they are empowered to help their country overcome its energy challenges.”

Graduate exchange student Nafeesa Irshad said there are “very few females in Pakistan in the energy field. We are going to take the lead.”

Irshad said of her experience at ASU thus far that “people are very supportive and helpful.”

Future cohorts of exchange students will arrive at ASU each semester through 2019 to help bolster the exchange of culture and research between the United States and Pakistan.

Erika Gronek

Communications Specialist, Ira A. Fulton Schools of Engineering