Solar Energy

Harvesting light like nature does

Published

3 years ago

June 5, 2021

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Inspired by nature, researchers at Pacific Northwest National Laboratory (PNNL), along with collaborators from Washington State University, created a novel material capable of capturing light energy. This material provides a highly efficient artificial light-harvesting system with potential applications in photovoltaics and bioimaging.

The research provides a foundation for overcoming the difficult challenges involved in the creation of hierarchical functional organic-inorganic hybrid materials. Nature provides beautiful examples of hierarchically structured hybrid materials such as bones and teeth. These materials typically showcase a precise atomic arrangement that allows them to achieve many exceptional properties, such as increased strength and toughness.

PNNL materials scientist Chun-Long Chen, corresponding author of this study, and his collaborators created a new material that reflects the structural and functional complexity of natural hybrid materials. This material combines the programmability of a protein-like synthetic molecule with the complexity of a silicate-based nanocluster to create a new class of highly robust nanocrystals. They then programmed this 2D hybrid material to create a highly efficient artificial light-harvesting system.

“The sun is the most important energy source we have,” said Chen. “We wanted to see if we could program our hybrid nanocrystals to harvest light energy – much like natural plants and photosynthetic bacteria can – while achieving a high robustness and processibility seen in synthetic systems.” The results of this study were published May 14, 2021, in Science Advances.

Big dreams, tiny crystals

Though these types of hierarchically structured materials are exceptionally difficult to create, Chen’s multidisciplinary team of scientists combined their expert knowledge to synthesize a sequence-defined molecule capable of forming such an arrangement. The researchers created an altered protein-like structure, called a peptoid, and attached a precise silicate-based cage-like structure (abbreviated POSS) to one end of it.

They then found that, under the right conditions, they could induce these molecules to self-assemble into perfectly shaped crystals of 2D nanosheets. This created another layer of cell-membrane-like complexity similar to that seen in natural hierarchical structures while retaining the high stability and enhanced mechanical properties of the individual molecules.

“As a materials scientist, nature provides me with a lot of inspiration” said Chen. “Whenever I want to design a molecule to do something specific, such as act as a drug delivery vehicle, I can almost always find a natural example to model my designs after.”

Designing bio-inspired materials

Once the team successfully created these POSS-peptoid nanocrystals and demonstrated their unique properties including high programmability, they then set out to exploit these properties. They programmed the material to include special functional groups at specific locations and intermolecular distances. Because these nanocrystals combine the strength and stability of POSS with the variability of the peptoid building block, the programming possibilities were endless.

Once again looking to nature for inspiration, the scientists created a system that could capture light energy much in the way pigments found in plants do. They added pairs of special “donor” molecules and cage-like structures that could bind an “acceptor” molecule at precise locations within the nanocrystal.

The donor molecules absorb light at a specific wavelength and transfer the light energy to the acceptor molecules. The acceptor molecules then emit light at a different wavelength. This newly created system displayed an energy transfer efficiency of over 96%, making it one of the most efficient aqueous light-harvesting systems of its kind reported thus far.

Demonstrating the uses of POSS-peptoids for light harvesting

To showcase the use of this system, the researchers then inserted the nanocrystals into live human cells as a biocompatible probe for live cell imaging. When light of a certain color shines on the cells and the acceptor molecules are present, the cells emit a light of a different color.

When the acceptor molecules are absent, the color change is not observed. Though the team only demonstrated the usefulness of this system for live cell imaging so far, the enhanced properties and high programmability of this 2D hybrid material leads them to believe this is one of many applications.

“Though this research is still in its early stages, the unique structural features and high energy transfer of POSS-peptoid 2D nanocrystals have the potential to be applied to many different systems, from photovoltaics to photocatalysis,” said Chen. He and his colleagues will continue to explore avenues for application of this new hybrid material.

Research paper

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Solar Energy

Addressing the dangers of lead pollution from solar power batteries in Africa

Published

24 mins ago

April 19, 2024

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Addressing the dangers of lead pollution from solar power batteries in Africa

by Sophie Jenkins

London, UK (SPX) Apr 19, 2024

A study conducted by The University of Manchester highlights significant health and environmental risks from the informal recycling of lead-acid batteries used in off-grid solar systems in Malawi. These batteries are essential for providing electricity in regions without traditional power grids, a crucial step towards broader electricity access across sub-Saharan Africa.

Researchers noted that a typical battery recycling process releases between 3.5 and 4.7 kg of lead, vastly exceeding safe levels by over 100 times the lethal dose for adults. Dr. Christopher Kinally, who led the study during his PhD, emphasized the dire need for structured waste management to mitigate these risks. According to him, “The expansion of solar power access is vital for sustainable development, but it must be paired with effective waste management strategies to avoid grave public health impacts.”

The private sector’s role in providing off-grid solar solutions is growing, with projections indicating potential electricity access for hundreds of millions by 2030. However, the absence of formal recycling practices in places like Malawi has resulted in dangerous lead exposure. Lead, a potent neurotoxin, poses severe risks, especially to children whose brain development can be permanently damaged even at low exposure levels.

The study also revealed alarming practices in local communities where technicians, lacking proper training in hazardous waste management, handle and recycle these batteries in open markets. Often, they use rudimentary tools to break open batteries and extract lead, significantly contaminating the environment.

Dr. Alejandro Gallego Schmid, Kinally’s supervisor, stated, “It’s crucial to address the lifecycle of batteries used in solar systems, from production to disposal, to maintain the sustainability credentials of solar energy.”

The findings, published in Applied Energy, are part of a broader investigation into the impacts of unregulated recycling practices in developing economies, emphasizing the urgent need for comprehensive research into their health implications and calling for immediate regulatory reforms.

Research Report:Life cycle assessment of solar home system informal waste management practices in Malawi

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Solar Energy

Momentus and Ascent Solar Technologies announce new solar array partnership

Published

1 day ago

April 18, 2024

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Momentus and Ascent Solar Technologies announce new solar array partnership

by Staff Writers

Momentus

by Clarence Oxford
Los Angeles CA (SPX) Apr 18, 2024
Momentus Inc. (NASDAQ: MNTS) and Ascent Solar Technologies (Nasdaq: ASTI) has unveiled their partnership aimed at jointly marketing innovative solar arrays that integrate Momentus’s low-cost Tape Spring Solar Array (TASSA) technology and Ascent’s advanced, flexible photovoltaic modules.

The surge in satellite production and deployment underscores a critical demand for affordable and efficient solar arrays. This collaboration will deliver a solar solution offering significant benefits including cost-effectiveness, durability under extreme space conditions, and high power output capabilities.

Following the successful initial demonstration of TASSA in orbit, launched via the Vigoride-6 mission, Momentus is enhancing the system with Ascent’s newer, more efficient Titan Module solar blankets. These upgrades aim to optimize power generation while reducing costs, with TASSA designed to support high-volume satellite operations by accommodating multiple units within standard launch payload configurations.

Rob Schwarz, CTO of Momentus, noted, “TASSA aims to empower small satellites with substantial power capabilities without compromising on mass, thermal management, or budget. This innovation not only maximizes space utilization within launch vehicles but also expedites satellite constellation deployment.”

The system’s adaptability includes retractable features to minimize exposure to space debris and adverse weather, potentially extending mission lifespans and operational reliability.

Paul Warley, CEO of ASTI, highlighted the suitability of their photovoltaic technology for space applications, emphasizing its durability and lightweight attributes which are critical in harsh orbital environments. “Our technology is designed to deliver sustained power output over time with significantly reduced mass, which is fundamental for successful long-term missions,” said Warley.

This partnership is set to streamline satellite array systems, making prolonged, cost-efficient space missions feasible.

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Solar Energy

Quantum material achieves up to 190% efficiency in solar cells

Published

1 day ago

April 18, 2024

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Quantum material achieves up to 190% efficiency in solar cells

by Clarence Oxford

Los Angeles CA (SPX) Apr 17, 2024

Researchers from Lehigh University have developed a material that significantly enhances the efficiency of solar panels.

A prototype incorporating this material as the active layer in a solar cell displays an average photovoltaic absorption rate of 80%, a high rate of photoexcited carrier generation, and an external quantum efficiency (EQE) reaching up to 190%. This figure surpasses the theoretical Shockley-Queisser efficiency limit for silicon-based materials, advancing the field of quantum materials for photovoltaics.

This work signifies a major advance in sustainable energy solutions, according to Chinedu Ekuma, professor of physics at Lehigh. He and Lehigh doctoral student Srihari Kastuar recently published their findings in the journal Science Advances. Ekuma highlighted the innovative approaches that could soon redefine solar energy efficiency and accessibility.

The material’s significant efficiency improvement is largely due to its unique intermediate band states, which are energy levels within the material’s electronic structure that are ideally positioned for solar energy conversion.

These states have energy levels in the optimal subband gaps-energy ranges capable of efficiently absorbing sunlight and producing charge carriers-between 0.78 and 1.26 electron volts.

Moreover, the material excels in absorbing high levels in the infrared and visible regions of the electromagnetic spectrum.

In traditional solar cells, the maximum EQE is 100%, which corresponds to the generation and collection of one electron for each photon absorbed. However, newer materials and configurations can generate and collect more than one electron per high-energy photon, achieving an EQE over 100%.

Multiple Exciton Generation (MEG) materials, though not yet widely commercialized, show immense potential for enhancing solar power system efficiency. The Lehigh-developed material utilizes intermediate band states to capture photon energy typically lost in traditional cells, including energy lost through reflection and heat production.

The research team created this novel material using van der Waals gaps, atomically small spaces between layered two-dimensional materials, to confine molecules or ions. Specifically, they inserted zerovalent copper atoms between layers of germanium selenide (GeSe) and tin sulfide (SnS).

Ekuma developed the prototype based on extensive computer modeling that indicated the system’s theoretical potential. Its rapid response and enhanced efficiency strongly indicate the potential of Cu-intercalated GeSe/SnS as a quantum material for advanced photovoltaic applications, offering a path for efficiency improvements in solar energy conversion, he stated.

While the integration of this quantum material into existing solar energy systems requires further research, the techniques used to create these materials are already highly advanced, with scientists mastering precise methods for inserting atoms, ions, and molecules.

Research Report:Chemically Tuned Intermediate Band States in Atomically Thin CuxGeSe/SnS Quantum Material for Photovoltaic Applications