Saturday, March 02, 2024

 

Guiding future research on ‘extraordinary potential’ of next-generation solar cells


Peer-Reviewed Publication

TSINGHUA UNIVERSITY PRESS

The potential of perovskite solar cells 

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RESEARCHERS AT SOOCHOW UNIVERSITY REVIEWED THE CURRENT DEVELOPMENTS IN MAKING PEROVSKITE SOLAR CELLS MORE EFFICIENT AND OFFER DIRECTIONS TO GUIDE FUTURE RESEARCH. THEY CURRENTLY CAN ACHIEVE SLIGHTLY MORE THAN 25% EFFICIENCY BUT THE RESEARCH SAID THEY COULD ACHIEVE MORE IF CURRENT LIMITATIONS ARE ADDRESSED APPROPRIATELY.

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CREDIT: FENGREN CAO, SOOCHOW UNIVERSITY




Today’s commercial solar panels can convert about 15% to 20% of the sunlight they absorb into electrical energy — but they could be much more efficient, according to researchers at Soochow University. The next generation of solar cells has already demonstrated 26.1% efficiency, they said, but more specific research directions are needed to make such efficiency the standard and expand beyond it.

 

They published their review of the current state of research on high-efficiency perovskite solar cells and their recommendations for future work in Energy Materials and Devices on February 4.

 

“Metal halide perovskite solar cells are a new type of high-performance solar cell,” said first author Fengren Cao, researcher in Soochow University’s School of Physical Science and Technology. “They exhibit excellent photoelectric properties and have the potential for high efficiency and low cost, making them a promising candidate for future solar energy applications.”

 

The metal halide perovskite in these solar cells is a calcium titanium oxide-like organic material that operates as a light-absorbing semiconductor to capture incidental sunlight and convert it to energy.

 

“Perovskite solar cells offer high efficiency, exceeding 26% in laboratory conditions; low cost, using relatively inexpensive materials and simple manufacturing processes; flexibility, as they can be made on flexible substrates — such as plastic or metal foils — enabling the development of lightweight, flexible photovoltaic devices; and they can be scaled up to larger sizes,” Cao said. “They have extraordinary potential as the next generation of photovoltaic technology.”

 

However, Cao noted, only a few research teams have developed perovskite solar cells capable of 25% efficiency or more.  

 

“Over the past years, many strategies have been adopted to improve the efficiency of perovskite solar cells,” Cao said. “But achieving more than 25% efficiency is not yet common. As such, in this paper, we summarize recent developments in high-efficiency perovskite solar cells and highlight their effective strategies in crystal regulation, interface passivation and structural design of component layers.”

 

These strategies could effectively address the main causes of low efficiency, which are preparation process-induced defects and an unsuitable band structure, according to Cao. The band structure refers to the energy levels of electrons in the material: Too low and the cell cannot properly or efficiently convert sunlight into energy, too high and the cell faces the same issue.

 

Cao also noted that other types of solar cells could be combined to construct “tandem solar cells” that could work together to break efficiency limits of a single type of solar cell. In addition, Cao said, fabrication methods for larger components need to be optimized to achieve the same efficiencies as the methods to fabricate small areas less than a 10th of a square centimeter.

 

“We believe that perovskite solar cells are one class of the most promising solar cells, and these efforts will ensure they can be commercialized and industrialized in the future,” Cao said, explaining that additional research would also address such challenges as tolerance to defects and issues related to stability. “The future of perovskite solar cells is incredibly exciting, and the potential for further advancements is vast.”

 

Other contributors include Liukang Bian and Liang Li, both with the School of Physical Science and Technology, Center for Energy Conversion Materials & Physics, Jiangsu Key Laboratory of Thin Films, Soochow University. Cao is also affiliated with Soochow University’s Jiangsu Key Laboratory of Advanced Negative Carbon Technologies.

 

The National Natural Science Foundation of China and the Priority Academic Program Development of Jiangsu Higher Education Institutions supported this work.

 


About Energy Materials and Devices

Energy Materials and Devices is launched by Tsinghua University, published quarterly by Tsinghua University Press, aiming at being an international, single-blind peer-reviewed, open-access and interdisciplinary journal in the cutting-edge field of energy materials and devices. It focuses on the innovation research of the whole chain of basic research, technological innovation, achievement transformation and industrialization in the field of energy materials and devices, and publishes original, leading and forward-looking research results, including but not limited to the materials design, synthesis, integration, assembly and characterization of devices for energy storage and conversion etc.

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Genetic research revealed several new fern species in tropical America


Peer-Reviewed Publication

UNIVERSITY OF TURKU

Danaea ubatubensis 

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DANAEA UBATUBENSIS, ONE OF THE RECENTLY DESCRIBED FERN SPECIES, IS KNOWN ONLY FROM A SMALL AREA OF COASTAL RAINFOREST IN BRAZIL. A LARGE PROPORTION OF THE SPECIES IN THE AREA ARE ENDEMIC.

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CREDIT: PHOTOGRAPHER: HANNA TUOMISTO




Researchers have clarified the evolutionary history of a previously poorly known group of ferns from the tropical rainforests of America using DNA methods. The study discovered many new fern species, 18 of which have now been given official names and species descriptions.

The Amazon Research Team of the University of Turku in Finland has conducted long-term studies on the flora and vegetation of Amazonian rainforests to gain a better understanding of species distribution and evolutionary history. The researchers have collected data from both Amazonia and other parts of tropical America. Now, they have traced the evolutionary history of the fern genus Danaea using DNA analyses.

"Studying the evolutionary relationships between species reveals factors that can lead to the differentiation of species traits and ultimately to the evolution of new species," says Doctoral Researcher Venni Keskiniva. "This type of information helps us understand the drivers behind the high biodiversity observed in tropical regions," Keskiniva continues.

The study revealed that there are many more species in the genus Danaea than previously thought, and as part of their revision, the researchers described 18 species that were new to science.

Genetics helped to distinguish between tricky species

In the study, the researchers combined DNA methods with solid field experience. Many of the new species were found in tropical rainforests in areas that had previously been studied little or not at all.

"However, some new species were growing right under the researchers’ noses, for example on Barro Colorado Island, which is one of the most intensively researched rainforests in the world. Two of our new species were found practically in the backyard of a research station," says Professor Hanna Tuomisto. "The plants had of course been seen, but they were thought to belong to a common species that grows throughout tropical America."

The recently published study shows that there are no such widespread species in the genus Danaea. Researchers have just been unable to distinguish between similar-looking species.

In the 1990s, it was estimated that the total number of Danaea species wass 20–30, and that many of them were very widespread. Today, there are about 80 named species, with a further 20 or so still awaiting confirmation. This means that the number of species is much higher, but their ranges are smaller than previously thought.

"At first, we were surprised to see that different individuals of a known species were placed in completely different parts of the family tree. Then we noticed that they formed groups that differed not only in DNA but also in appearance and area of occurrence. This led us to conclude that they were different species," explains Keskiniva.

Danaea ferns are notorious for being difficult to identify. Therefore, the researchers from the University of Turku also published an online identification key. This will help other researchers gather information on the ecology and species richness of tropical forests.

Several species are already endangered at the time of discovery

The ferns of the genus Danaea represent a very old evolutionary line, already differentiated from other plants in the Carboniferous Period. At that time, their ancestors formed vast fern forests, the fossilised remains of which later became coal.

As a result of the burning of the coal and other fossil fuels, the climate of tropical rainforests is becoming hotter and drier. This is threatening the future of species adapted to high humidity, such as Danaea ferns. The researchers estimate that six of the now described 18 species are already endangered.

"Suitable habitats for rainforest species have been reduced due to direct human activity, such as deforestation" says Tuomisto. "The situation is especially bad in the rainforests of the Atlantic coast, Andean montane forests, and parts of the Pacific coast and Central America. These areas are rich in endemic species, but the forests have been reduced to fragments. For understanding and protecting the biodiversity of tropical forests, it is important to realise that species distributions are narrower than used to be thought".

Danaea ampla, one of the new fern species recently described, was found in Panama on Barro Colorado Island, which is one of the most intensively researched rainforest sites in the world.

CREDIT

Photographer: Hanna Tuomisto

 

Black mountain unveils fossil trove


New revelations poised to reshape our understanding of early cephalopod evolution


Peer-Reviewed Publication

PEERJ

Possible life reconstructions of Sinoeremoceras marywadeae sp. nov. 

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NOTE THAT THESE RECONSTRUCTIONS CORRESPOND TO TWO EXTREMES TO SHOW THE POSSIBLE RANGE OF INTERPRETATION BASED ON PHYLOGENETIC BRACKETING. THE LEFT RECONSTRUCTION IS INSPIRED BY A LIMPET-LIKE SOFT PART ANATOMY AS IN LIVING MONOPLACOPHORANS (E.G., Wingstrand, 1985Ruthensteiner, Schröpel & Haszprunar, 2010), WITHOUT TYPICAL CEPHALOPOD AUTAPOMORPHIES SUCH AS EYES, ARMS AND HYPONOME. THE RIGHT RECONSTRUCTION REPRESENTS SOFT PART ANATOMY THAT WOULD BE EXPECTED CLOSE TO THE CEPHALOPOD CROWN GROUP (E.G., Kröger, Vinther & Fuchs, 2011Klug et al., 2015).

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CREDIT: CREDIT: EVELYN FRIESENBICHLER.




A team of researchers led by Alexander Pohle has unveiled a treasure trove of ancient fossils from Queensland's Black Mountain. The findings, published in PeerJ Life & Environment, shed new light on the complex three-dimensional siphuncle morphology of Plectronoceratids, a pivotal group of molluscs from the latest Cambrian period.

The study surpasses the entirety of previously documented Plectronoceratid fossils, presenting over 200 well-preserved specimens. These fossils, meticulously collected by the late Mary Wade and her team during the 1970s and 1980s, offer unprecedented insights into the intricate structures of these ancient creatures.

Pohle's team focused on specimens from the lower Ninmaroo Formation at Black Mountain, meticulously examining the three-dimensional morphology of the siphuncle. This comprehensive analysis revealed a remarkably intricate siphuncular structure, challenging previous interpretations based on longitudinal sections and prompting a major revision of the taxonomic classification within the order Plectronoceratida.

Of particular note is the discovery of Sinoeremoceras marywadeae sp. nov., a new species named in honor of Mary Wade. This species, characterized by its highly oblique siphuncular segments and elongated septal neck, represents a significant addition to the cephalopod evolutionary tree. Moreover, the study advocates for a revised taxonomy, consolidating multiple species, genera, families and even one order under the Plectronoceratida.

Pohle expressed his gratitude to Mary Wade, whose dedication to specimen collection and preparation paved the way for this groundbreaking research. "Would it not be for her, these faunas would still largely be unknown," said Pohle. The team hopes that their work honors Wade's legacy, acknowledging the invaluable contributions she made to paleontological science.

As the scientific community delves deeper into the origins of cephalopods, Pohle's team emphasizes the significance of further exploration and advanced imaging techniques. They advocate for the use of 3D reconstructions, such as µCT scans or serial grinding tomography, to unlock new dimensions of understanding in research on Palaeozoic cephalopds.

The publication of this groundbreaking study marks a pivotal moment in our quest to unravel the mysteries of ancient marine life. With each fossil unearthed, we inch closer to a comprehensive understanding of Earth's prehistoric past.

 

Eco-labeling: self or certification?

Peer-Reviewed Publication

KEAI COMMUNICATIONS CO., LTD.

WHICH ECO-LABEL SHOULD THE MANUFACTURER CHOOSE? 

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WHICH ECO-LABEL SHOULD THE MANUFACTURER CHOOSE?

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CREDIT: GAOXIANG, L., ET AL.




The green lifestyle has been increasingly popular in recent years. According to the 2023 China Consumption Trend Report, 73.8% of customers prioritize buying environmentally friendly products. Tools such as eco-labels are widely used by companies to show consumers how green their products are.

Eco-label comes in the form of certification label or self-labeling, depending on the originator. Certification label is issued by third-party certification bodies, such as Energy Star and Organic Food. While they are trusted by consumers, it is difficult to convey green attributes beyond the standard to consumers. Self-labeling, such as Wal-Mart's natural label, is the manufacturer's self-declaration of the product's green status on the packaging, but consumers often have low trust in it.

In this context, a research team led by Professor Gaoxiang Lou of East China University of Science and Technology and Professor Yi-Ming Wei of Beijing Institute of Technology constructed a green supply chain game model which includes a manufacturer and a supplier. The supplier provides green raw materials, and the manufacturer carries out green manufacturing and chooses eco-label for products.

The researchers found that upstream and downstream companies in the supply chain have conflicting eco-label selection preferences. The supplier prefers certification label, while the manufacturer tends to choose self-labeling, although the social welfare under certification label may be higher. According to this discovery, further coordination among supply chain members is needed to address conflicting preferences.

Further, the researchers expanded the certification label level from the original single level to multiple levels. For example, Cradle to Cradle Certified is divided into five levels. The results indicate that when consumers have low trust in self-labeling and the difficulty of green investment is low, the manufacturer is more likely to choose multi-level certification labels. This gives a scientific basis for the formulation of multi-level eco-label.

Besides, the researchers found an interesting result - when companies adopt single-level certification label, consumers' green preferences can be harmful to companies’ profitability. They explained, "As consumers' green preferences increase, certification agencies will issue more strict certification standards. This will force companies to invest more in green innovation, thereby damaging their profitability."

Finally, the researchers, who published their findings in the KeAi journal Sustainable Operations and Computers, stated, "We simultaneously consider green supplying, green manufacturing, and eco-label selection behaviors in the green supply chain, and further extend to multi-level eco-label, which is rare in existing research". Their results can provide reference for the green innovation practice and eco-label strategy selection in green supply chain.

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Contact the author: Haicheng Ma, Center for Energy and Environmental Policy Research, Beijing Institute of Technology, Beijing, China, mahaicheng@bit.edu.cn or hcm@mail.ecust.edu.cn

The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 100 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).