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New perovskite LED emits a spin-polarized glow

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New perovskite LED emits a spin-polarized glow

The inclusion of a special new perovskite layer has enabled scientists to create a “spin-polarized LED” without needing a magnetic field or extremely low temperatures, potentially clearing the path to a raft of novel technologies.

Details of the research conducted at the National Renewable Energy Laboratory (NREL) and the University of Utah appear in the journal Science.

Researchers at NREL and around the world have been investigating the use of perovskite semiconductors for solar cells that have proven to be highly efficient at converting sunlight to electricity. Since a solar cell is one of the most demanding applications of any semiconductor, scientists are discovering other uses exist as well.

“We are exploring the fundamental properties of metal-halide perovskites, which has allowed us to discover new applications, beyond photovoltaics,” said Joseph Luther, a co-author of the new paper, “Chiral-induced spin selectivity enabling a room-temperature spin light-emitting diode.” “Because metal-halide perovskites, and other related systems, are some of the most fascinating semiconductors, they exhibit a host of novel phenomena that can be utilized in transforming energy.”

The other co-authors from NREL are Matthew Beard, a senior research fellow and director of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), Young-Hoon Kim, Yaxin Zhai, Haipeng Lu, Chuanxiao Xiao, E. Ashley Gaulding, Steven Harvey, and Joseph Berry. Valy Vardeny and Xin Pan are co-authors from Utah. All are part of CHOISE, an Energy Frontier Research Center (EFRC) funded by the Office of Science within DOE.

The goals of the CHOISE EFRC are to control the interconversion of charge, spin, and light using carefully designed chemical systems. Most opto-electronic devices in use today only control charge and light and not the spin of the electron. An electron can have either “up” or “down” spins. Using two different perovskite layers, the researchers were able to control the spin by creating a filter that blocks electrons “spinning” in the wrong direction.

One way to produce spin-polarized currents is through a “chiral-induced spin selectivity” layer, where the transport of electrons with “up” or “down” spin states depends upon the chirality of the transporting materials. Chirality refers to the materials structure where it is not identical to its mirror image. For example, a “left-handed” oriented chiral system may allow transport of electrons with “up” spins but block electrons with “down” spins and vice versa.

The filter enabled the researchers to inject spin-polarized charges into a light-emitting diode (LED) at room temperature–instead of at hundreds of degrees below zero Fahrenheit–and without the use of magnetic fields or ferromagnetic contacts that are typically needed to control the spin degree of freedom.

The LED, in response, emits light with special chiral properties, accordingly. The concept proves that using these chiral-hybrid systems gains control over spin without magnets and has “broad implications for applications such as quantum-based optical computing, bioencoding, and tomography,” according to Beard.



SOLAR DAILY
Producing highly efficient LEDs based on 2D perovskite films

Hong Kong (SPX) Mar 11, 2021


Energy-efficient light-emitting diodes (LEDs) have been used in our everyday life for many decades. But the quest for better LEDs, offering both lower costs and brighter colours, has recently drawn scientists to a material called perovskite. A recent joint-research project co-led by the scientist from City University of Hong Kong (CityU) has now developed a 2D perovskite material for the most efficient LEDs.

From household lighting to mobile phone displays, from pinpoint lighting needed for endosc … read more

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More energy and oil possible through combining photovoltaic plants with hedgerow olive groves

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More energy and oil possible through combining photovoltaic plants with hedgerow olive groves


More energy and oil possible through combining photovoltaic plants with hedgerow olive groves

by Hugo Ritmico

Madrid, Spain (SPX) Nov 20, 2024






The integration of photovoltaic plants on agricultural land has long sparked debate over balancing energy production with crop cultivation. Now, the innovative approach of combining both has gained momentum with promising results. This “agrivoltaic” system, which involves placing solar panels within agricultural setups, has been examined by a University of Cordoba research team to see if solar energy and agricultural production could mutually enhance each other.

The research group, including Marta Varo Martinez, Luis Manuel Fernandez de Ahumada, and Rafael Lopez Luque from the Physics for Renewable Energies and Resources group, along with Alvaro Lopez Bernal and Francisco Villalobos from the Soil-Water-Plant Relations group, developed a model that simulates an agrivoltaic system in hedgerow olive plantations. This simulation model combined predictions for oil yield from olive hedgerows and energy generation from solar collectors to assess combined productivity. The study concluded that using both in tandem increased overall productivity, marking a potential shift in land-use strategy that could cater to the needs for both clean energy and food.



The key findings show that mutual benefits arise when solar panels provide shade, acting as windbreaks that don’t compete for water, enhancing agricultural production. Meanwhile, the cooling effect from plant evapotranspiration can improve the efficiency of solar collectors by reducing their temperature, boosting energy output.



This model allows researchers to experiment with various collector configurations, adjusting heights, widths, and spacing, to pinpoint the most effective designs. Despite generally positive outcomes, the team noted that overly dense arrangements might limit space for machinery or complicate maintenance of the olive grove. The approach underscores the importance of balancing land-use density and operational accessibility.



Research Report:Simulation model for electrical and agricultural productivity of an olive hedgerow Agrivoltaic system


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New initiative empowers Native American women with solar training

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New initiative empowers Native American women with solar training


New initiative empowers Native American women with solar training

by Clarence Oxford

Los Angeles CA (SPX) Nov 20, 2024







Native American women across the country are gaining access to hands-on training in photovoltaic panel installation aimed at empowering them to establish solar systems in their communities and homes on tribal land.

Sandra Begay, an engineer at Sandia National Laboratories and a Navajo Nation member, is one of four mentors guiding this effort.



This training initiative is part of a Cooperative Research and Development Agreement between Sandia and Red Cloud Renewable, a nonprofit organization in Pine Ridge, South Dakota, that focuses on advancing energy independence for tribal members and communities.



Known as the Bridging Renewable Industry Divides in Gender Equality, or BRIDGE, Program, the initiative provides a five-week immersive training experience that emphasizes practical skills in photovoltaic installation.



In August, Begay joined the first group of participants in South Dakota.



“Five weeks is a long time to be away from home,” Begay said. “I provided encouragement and reminded the women that they made the right choice to participate in this program. We also used the time to reflect on what they learned.”



Participants are taught the components of photovoltaic systems and how to install them safely and effectively.



Begay also provided insight into the energy challenges faced by tribal communities.



“There are more than 20,000 homes on the Navajo Nation and some rural homes on the Hopi reservation that don’t have electricity. These are off-grid homes,” Begay said, noting that many of these homes depend on diesel generators. “We’re looking at a clean energy future. We want to move away from those types of fuels and look at clean energy sources such as solar.”



She highlighted that large-scale solar projects are being developed by the Navajo Nation and the Mountain Ute Tribe in Colorado.



“This program will provide participants with new employment opportunities and a better understanding of where we’re headed with clean energy,” Begay said.



Red Cloud Renewable also supports the women with resume building, interview training, networking, and job placement services.



With over 30 years of experience championing renewable energy in Native American communities, Begay is committed to maintaining relationships with participants.



“I am making a long-term commitment to the women in the BRIDGE Program,” Begay said. “I will share any job openings I see with them and support them in their job searches.”



Teamwork for success

Begay emphasized the critical role teamwork plays in photovoltaic installations.



“Photovoltaic installation happens with a team of people. How do you work through that group dynamic? How do you work with each other as a team? Those questions are underemphasized in the work we do. They’re going to rely on each other when installing photovoltaic systems,” she said.



Alicia Hayden, Red Cloud Renewable’s communications manager, noted the strong bond formed among the participants.



“What stood out to me was the incredible camaraderie among the women,” Hayden said. “They were genuinely supportive of each other and grateful to be participating in this program alongside women who share similar backgrounds.”



Funded by the Department of Energy’s Solar Energy Technology Office, the project is set to continue over the next few years and aims to train two additional groups, eventually involving around 45 women.



“These women will be equipped to take on installer jobs within their own reservations, bringing valuable skills and opportunities for sustainable development to their people,” Hayden said.



Despite being highly underrepresented in the solar industry – comprising just 0.05% of the sector, according to Red Cloud Renewable – Native American women stand to gain from this initiative.



Begay expressed optimism about the impact of the BRIDGE Program.



“It’s very gratifying both professionally and personally to see where we can help women who are underrepresented in the workforce, let alone in a unique technology like photovoltaic installation,” Begay said. “We’re seeding ideas for the women that they would never have thought of doing. I think that’s what’s unique.”


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Perovskite advancements improve solar cell efficiency and longevity

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Perovskite advancements improve solar cell efficiency and longevity


Perovskite advancements improve solar cell efficiency and longevity

by Sophie Jenkins

London, UK (SPX) Nov 20, 2024






A global team led by the University of Surrey, in collaboration with Imperial College London, has pioneered a method to enhance the efficiency and durability of solar cells constructed from perovskite by addressing an unseen degradation pathway.

The University of Surrey’s Advanced Technology Institute (ATI) detailed their findings in ‘Energy and Environmental Science’, showing that by employing specific design strategies, they successfully created lead-tin perovskite solar cells achieving over 23% power conversion efficiency (PCE) – a significant result for this material type. Notably, these improvements also boosted the operational lifespan of these cells by 66%. PCE measures the proportion of sunlight converted to usable energy by a solar cell.



While traditional silicon solar panels are already widely used, advancements are steering towards perovskite/silicon hybrid panels, and fully perovskite-based panels promise even higher efficiencies. However, improving the stability and efficiency of lead-tin perovskite cells remains a significant hurdle. This research by the University of Surrey sheds light on mechanisms contributing to these limitations and offers a pathway to overcoming them, aiding in the broader advancement of solar technology.



Hashini Perera, Ph.D. student and lead author at ATI, stated: “The understanding we have developed from this work has allowed us to identify a strategy that improves the efficiency and extends the operational lifetime of these devices when exposed to ambient conditions. This advancement is a major step towards high efficiency, long-lasting solar panels which will give more people access to affordable clean energy while reducing the reliance on fossil fuels and global carbon emissions.”



The team focused on minimizing losses caused by the hole transport layer, crucial for solar cell functionality. By introducing an iodine-reducing agent, they mitigated the degradation effects, enhancing both the cell’s efficiency and its lifespan. This innovation paves the way for more sustainable and economically feasible solar technology.



Dr. Imalka Jayawardena from the University of Surrey’s ATI, co-author of the study, said: “By significantly enhancing the efficiency of our perovskite-based solar cells, we are moving closer to producing cheaper and more sustainable solar panels. We are already working on refining these materials, processes and the device architecture to tackle the remaining challenges.”



Professor Ravi Silva, Director of the ATI, added: “This research brings us closer to panels that not only generate more power over their lifetime but are also longer lasting. Greater efficiency and fewer replacements mean more green energy with less waste. The University of Surrey are in the process of building a 12.5MW solar farm, where we can test some of these modules. We’re confident that our innovative perovskite research will accelerate the widespread commercial adoption of perovskite-based solar panels.”



This progress aligns with the UN Sustainable Development Goals, specifically Goals 7 (affordable and clean energy), 9 (industry, innovation, and infrastructure), and 13 (climate action).



Research Report:23.2% efficient low band gap perovskite solar cells with cyanogen management


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