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Progress On Perovskite Solar Cells | Earth Wise

August 2, 2022 By EarthWise Leave a Comment

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Perovskites are semiconductors with a specific crystal structure. Their properties make them well suited for making solar cells. They can be manufactured at room temperature, using much less energy than it takes to make the silicon-based solar cells widely used today. As a result, perovskite solar panels would be cheaper and more sustainable to produce. Manufacturing silicon solar cells takes a lot of energy because silicon is forged at around 3000 degrees Fahrenheit. In addition, perovskites can be made flexible and transparent, making it possible to use them in ways unavailable with silicon solar technology.

But unlike silicon, perovskites are very fragile. The early solar cells made from perovskites in 2009 and 2012 lasted for only minutes. Lots of potential, but little practicality.

Recently, Princeton Engineering researchers have developed the first perovskite solar cell with a commercially viable lifetime, which is a major breakthrough. The team projects that the device can perform above industry standards for about 30 years, which is much more than the 20 years designated as a viability threshold for commercial cells.

The research team has developed an ultra-thin capping layer between two of the layers of a perovskite solar cell. The layer is just few atoms thick but has been demonstrated to dramatically increase the durability of the device.

There is great potential for the new solar cell technology. It has efficiency to compete with silicon cells but can be tuned for specific applications and can be manufactured locally with low energy inputs. If successfully commercialized, the result will be solar panels that are cheaper, more efficient, and more flexible than what are available today.

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Once seen as fleeting, a new solar tech shines on and on

Photo, posted January 8, 2020, courtesy of David Baillot/UC San Diego Jacobs School of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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A New “Wonder Material” | Earth Wise

February 11, 2022 By EarthWise Leave a Comment

Graphene is a form of carbon made of single-atom-thick layers. It has many remarkable properties and researchers around the world continue to investigate its use in multiple applications.

In 2019, a new material composed of single-atom-thick layers was produced for the first time. It is phosphorene nanoribbons or PNRs, which are ribbon-like strands of two-dimensional phosphorous. These materials are tiny ribbons that can be a single atomic layer thick and less than 100 atoms wide but millions of atoms long. They are comparable in aspect ratio to the cables that span the Golden Gate Bridge. Theoretical studies have predicted how PNR properties could benefit all sorts of devices, including batteries, biomedical sensors, thermoelectric devices, nanoelectronics, and quantum computers.

As an example, nanoribbons have great potential to create faster-charging batteries because they can hold more ions than can be stored in conventional battery materials.

Recently, for the first time, a team of researchers led by Imperial College London and University College London researchers has used PNRs to significantly improve the efficiency of a device. The device is a new kind of solar cell, and it represents the first demonstration that this new wonder material might actually live up to its hype.

The researchers incorporated PNRs into solar cells made from perovskites. The resultant devices had an efficiency above 21%, which is comparable to traditional silicon solar cells. Apart from the measured results, the team was able to experimentally verify the mechanism by which the PNRs enhanced the improved efficiency.

Further studies using PNRs in devices will allow researchers to discover more mechanisms for how they can improve performance.

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‘Wonder material’ phosphorene nanoribbons live up to hype in first demonstration

Photo, posted October 6, 2010, courtesy of Alexander AlUS / CORE-Materials via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transparent Wood | Earth Wise

June 14, 2021 By EarthWise Leave a Comment

In recent years, there have been efforts to change the nature of wood to give it new properties. People have demonstrated so-called augmented wood with integrated electronics, energy storage capabilities, and other properties. Several different groups of researchers have developed wood that is actually transparent.

In 2016, researchers at KTH Royal Institute of Technology in Stockholm demonstrated transparent wood made by selectively extracting lignin – the substance that makes up the cell walls of wood -and replacing it with a polymer. The result is a new material that is weatherproof, fairly fire resistant, stronger than wood, lighter than wood, and transparent.

When the lignin is removed from wood, the empty pores left behind need to be filled with something that restores the wood’s strength. The early versions of transparent wood used polymethyl methacrylate – essentially acrylic plastic – for this purpose. But that material is made from petroleum, so it is not an environmentally desirable approach.

Recently, the KTH researchers have successfully tested an eco-friendly alternative: limonene acrylate, which is a monomer made from renewable citrus, such as peel waste that can be recycled from the orange juice industry.

There are many potential applications for transparent wood as a structural material. These include load-bearing windows, skylights, and semi-transparent facades that are strong and thermally insulating and yet permit light to enter.

Transparent wood would be a very attractive material for many applications in that it comes from renewable sources and offers excellent mechanical properties including strength, toughness, low density, and low thermal conductivity.

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Citrus derivative makes transparent wood 100 percent renewable

Photo, posted October 12, 2018, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Breaking Down Polystyrene | Earth Wise

April 20, 2021 By EarthWise Leave a Comment

The proliferation of global plastic waste continues to be a growing problem for the world. Hundreds of millions of tons of plastics are produced each year and most of it is used once and then discarded. The properties that make plastics so attractive – durability and chemical stability – make it difficult to do anything with discarded plastics other than deposit them in landfills – where they don’t easily degrade over time – or burn them, which dumps carbon dioxide and various hazardous gases into the atmosphere.

Polystyrene is one of the most widely used plastics. It is found in foam packaging materials, disposable food containers, plastic cutlery, storage containers, and many other places.

Recycling plastics like polystyrene is generally not economically feasible. Sorting plastics by type is time and labor intensive and the chemical processes required to break down plastics into usable precursor materials require significant energy input and the use of toxic solvents.

Recently, a team of scientists at Ames Laboratory in Iowa has developed a process based on ball-milling that deconstructs commercial polystyrene in a single step, at room temperature, in ambient atmosphere, and in the absence of harmful solvents.

Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated to initiate a chemical reaction. This approach is known as mechanochemistry.

The method represents an important breakthrough that enables dismantling of a polymer that includes its chemical breakdown without requiring solvents or the high temperatures generally needed to thermally decompose it. This discovery opens up new avenues for low-temperature recovery of monomers from polymer-based systems that include composites and laminates. It could be a very useful weapon in the battle against plastic waste.

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Polystyrene waste is everywhere, and it’s not biodegradable. Scientists just found a way to break it down.

Photo, posted December 11, 2010, courtesy of Warrenski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Palm Oil Replacement | Earth Wise

December 15, 2020 By EarthWise Leave a Comment

In the 1990s, cardiovascular health issues associated with partially hydrogenated oils containing harmful trans fats became a focus of great concern. As a result, food companies looked for substitutes and the alternative they identified was palm oil. Its ability to remain solid at room temperature made it well suited for many food applications. Unfortunately, that property stems from its high saturated fat content, which means it also increases the risk of coronary heart disease.

The widespread use of palm oil has also caused significant environmental problems. Palm oil plantations have replaced millions of acres of tropical forests, destroying the habitat for numerous species and threatening biodiversity.

Other potential replacements for partially hydrogenated oils such as coconut oil tend to be more costly, limited in supply, and also high in saturated fats.

Food scientists at the University of Guelph in Ontario, Canada, recently demonstrated the use of enzymatic glycerolysis (EG) to turn liquid vegetable oils into solid fats. Their process is able to produce solid fats with the textural and structural properties desired by consumers.

The process is fairly simple, relatively easy to scale up, and is amenable to smaller food production or even local production. Using it would enable food producers to use all sorts of readily available vegetable oils that can be produced in parts of the world that are not necessarily tropical regions.

Palm oil use is not going to go away, but this work may point a way to help slow down the destruction of ecosystems and animal habitats as well lead to more sustainable and healthy food sources.

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U of G Food Scientists Find Palm Oil Alternative That’s Good for Human, Planet Health

Photo, posted February 21, 2010, courtesy of Craig Morey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Bugs That Eat Plastic | Earth Wise

September 29, 2020 By EarthWise Leave a Comment

The world continues to struggle with the proliferation of plastic that is polluting the environment. The Great Pacific Garbage Patch has now grown so large that it has spread across an area four times the size of California. But there is no silver bullet in the struggle to reduce plastic pollution. Reducing the use of plastic is probably the most viable approach, but increased recycling, the use of bioplastics, and various other strategies must play a role.

The essence of the problem is that plastic takes from decades to hundreds of years to decompose naturally. The world produces billions of tons of plastic waste each year and less than 10% of it is recycled. As a result, researchers around the world seek ways to safely and economically accelerate the decomposition of plastics.

A research team at Andong National University in South Korea has discovered the larvae of a particular species of darkling beetle can decompose polystyrene, which is one of the trickiest plastics to break down. There are thousands of species of darkling beetles found in different habitats all over the world. The one they identified is indigenous to East Asia.

The beetle larvae can consume polystyrene and reduce both its mass and molecular weight. Furthermore, they found that the bacteria in the gut of the larvae could oxidize and change the surface property of polystyrene. The handful of bacterial strains they identified were not like those of earlier insects found to degrade polystyrene. As result, the researchers are hopeful that it may be possible to break down the plastic using other insects that feed on rotten wood. Apart from the insects themselves, using just the bacterial strains found in the darkling beetles may prove to be an effective method for decomposing polystyrene.

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A New Species of Darkling Beetle Larvae That Degrade Plastic

Photo courtesy of Flickr.

I farmaci a base di erbe e omeopatici rappresentano una percentuale significativa (circa una confezione su otto) dell’assortimento da banco delle farmacie. Nel 2017, i farmaci a base di erbe hanno registrato vendite per 1,48 milioni di euro e 120 milioni di confezioni, mentre maschioforte.com i farmaci omeopatici hanno registrato vendite per 630 milioni di euro e 52 milioni di confezioni, secondo l’Associazione federale dell’industria farmaceutica (Bundesverband der Pharmazeutischen Industrie – BPI).

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Forests As Carbon Sinks | Earth Wise

April 21, 2020 By EarthWise Leave a Comment

Tropical forests are an important part of the global carbon cycle because they take up and store large amounts of carbon dioxide. Because of this, deforestation in the Amazon and other tropical forests is a major contributor to the growing CO2 levels in the atmosphere.

Therefore, climate models need to accurately take into account the ability of tropical forests to sequester carbon. It turns out that this is not such a simple matter. A new study by the International Institute for Applied Systems Analysis sought to determine how much detail about tropical forests is needed in order to make valid assumptions about the strength of forest carbon sinks.

They looked at the role of both biotic factors – differences between plant species that are responsible for capturing more or less carbon from the atmosphere – and abiotic factors – local environmental factors like soil properties that also influence carbon sink strength.

It is generally assumed that more diverse forest communities capture available resources more efficiently as a result of complementary characteristics and preferences of certain species to specific conditions. Factors like soil texture and chemistry are also important. In general, the results show that abiotic and biotic factors interact with one another to determine how much carbon can be stored by the ecosystem.

Traditional projections of the role of tropical forests in storing carbon mostly rely on remote sensing techniques that integrate over large spatial areas. The new study shows that there can be large differences in the carbon storing ability of tropical forests and that more detailed models are needed to produce more accurate projections.

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Shedding light on how much carbon tropical forests can absorb

Photo, posted July 17, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Another Way To Make Solar Cells

March 21, 2019 By EarthWise Leave a Comment

Millions of rooftops now contain solar panels and the majority of the solar cells that make up those panels today are made from silicon. Silicon solar cells require expensive, multi-step processing conducted at very high temperatures in special clean room facilities. Despite these complications, the price of solar panels has continued to drop dramatically over the years.

But even as the price of solar cells gets lower and lower, there are still widespread efforts to find even better ways to make them. One of those ways is with perovskite solar cells. Perovskites are materials with a characteristic crystal structure and are quite common in nature. Perovskites can be formed with a wide range of elements and can exhibit a variety of properties.

They were first used to make solar cells about 10 years ago and those first cells were unimpressive in most respects. However, there has been steady progress since that time. The potential advantages of perovskite solar cells are that they can be made from low-cost materials and can be manufactured using liquid chemistry, a far cheaper process than what is used to make silicon cells.

Researchers at MIT and several other institutions have recently published the results of research on how to tailor the composition of perovskite solar cells to optimize their properties. What used to be a trial-and-error process can now become much more engineered and should lead to perovskite solar cells with performance that could exceed that of silicon cells.

Silicon solar panels are a huge, worldwide industry and displacing them in favor of an alternative technology is a tall order. But if perovskite cells can be optimized for large-scale manufacturability, efficiency and durability, they could definitely give silicon a run for its money.

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Unleashing perovskites’ potential for solar cells

Photo courtesy of Ken Richardson/MIT.

Earth Wise is a production of WAMC Northeast Public Radio.

Infinitely Recyclable Plastic

June 8, 2018 By EarthWise Leave a Comment

Less than 10% of discarded plastic is recycled. This is one of the major reasons that plastic waste is such a threat to the environment. There are many challenges to recycling plastics. For one thing, there are many different types of plastic and if they are melted together, they tend to phase-separate like oil and water and the resultant substance is structurally weak. Sorting plastics by type is not a simple task. More generally, it is very difficult to produce plastic with its original properties from recycled feedstock. So recycled plastics generally end up being useful in only more limited applications.

Mass Production Of Biodegradable Plastic

October 17, 2017 By EarthWise 1 Comment

Plastic pollution is a major problem for the world’s oceans and non-biodegradable plastics continue to fill the planet’s landfills and litter the landscape. There are many approaches to making plant-derived, biodegradable plastics but most of these materials do not offer the resistance to heat and moisture that is characteristic of petroleum-based plastics.