TL;DR

• MIT researchers developed a scalable fabrication technique to produce ultrathin, flexible, durable, lightweight solar cells that can be stuck to any surface. Glued to high-strength fabric, the solar cells are only one-hundredth the weight of conventional cells while producing about 18 times more power-per-kilogram.
• Clean, sustainable energy solutions are essential to meet the ever-increasing energy demands of the human population. High efficiency solar cells are promising candidates to reduce carbon emissions and achieve carbon neutrality. In this regard, solution-processed copper indium gallium sulfur diselenide solar cells (CIGSSe) solar cells have generated significant interest owing to their excellent photovoltaic properties, such as high absorption of visible light, stability, and tunable bandgap. However, large scale, practical applications are limited by a two-fold challenge.
• Researchers have demonstrated a new way to create stable perovskite solar cells, with fewer defects and the potential to finally rival silicon’s durability.
• Tin sulfide (SnS) solar cells have shown immense promise in the rush to develop more environmentally friendly thin-film solar cells. Yet for years SnS solar cells have struggled to achieve a high conversion efficiency. To overcome this, a SnS interface exhibiting large band bending was necessary, something a research group has recently achieved.
• The energy and health challenges of the human population require the development of advanced materials. In this regard, 3D COFs with their net-like structures and unprecedented porosity show promise. But their synthesis from pre-designed building units is extremely challenging. To this end, researchers have now developed TUS-84, the first 3D COF with a unique scu-c network structure, with enormous potential in drug delivery and clean energy.
• Researchers have used gold extracted from electronic waste as catalysts for reactions that could be applied to making medicines.
• Electric cars — and their continued sales growth — are expected to have a greener, cleaner influence on air pollution and reduce early human mortality in most, if not all, U.S. metropolitan areas.
• An almost limitless supply of fresh water exists in the form of water vapor above Earth’s oceans, yet remains untapped, researchers said. A new study suggests an investment in new infrastructure capable of harvesting oceanic water vapor as a solution to limited supplies of fresh water in various locations around the world.
• By assessing so-called ‘flavors’ of El Nino events in past climate records and model simulations, researchers have a clearer picture of El Nino patterns over the past 12,000 years and are able to more accurately project future changes and impacts of this powerful force.
• A new study finds that the health benefits associated with wind power could more than quadruple if operators turned down output from the most polluting fossil-fuel-based power plants when energy from wind is available. However, compared to wealthier communities, disadvantaged communities would reap a smaller share of these benefits.
• And more!

Green Technology Market

Green technology is an applicable combination of advanced tools and solutions to conserve natural resources and environment, minimize or mitigate negative impacts from human activities on the environment, and ensure sustainability development. Green technology is also referred to as clean technology or environmental technology which includes technologies, such as IoT, AI, analytics, blockchain, digital twin, security, and cloud, which collect, integrate, and analyze data from various real-time data sources, such as sensors, cameras, and Global Positioning System (GPS).

Green technology, also known as sustainable technology, protects the environment by using various forms of sustainable energy. Some of the best examples of green technologies include solar panels, LED lighting, wind energy, electric vehicles, vertical farming, and composting.

The global Green Technology and Sustainability market size to grow from USD 11.2 billion in 2020 to USD 36.6 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 26.6% during the forecast period. The growing consumer and industrial interest for the use of clean energy resources to conserve environment and increasing use of Radio Frequency Identification sensors across industries are driving the adoption of green technology and sustainability solutions and services in the market.

The blockchain segment is estimated to grow at the highest CAGR: Energy-intensive cryptocurrency mining has caused a spike in carbon emission, and hence blockchain is capable of driving innovation in the field of green technology.

Latest Research

Printed Organic Photovoltaic Modules on Transferable Ultra‐thin Substrates as Additive Power Sources

by Mayuran Saravanapavanantham, Jeremiah Mwaura, Vladimir Bulović in Small Methods

MIT engineers have developed ultralight fabric solar cells that can quickly and easily turn any surface into a power source.

These durable, flexible solar cells, which are much thinner than a human hair, are glued to a strong, lightweight fabric, making them easy to install on a fixed surface. They can provide energy on the go as a wearable power fabric or be transported and rapidly deployed in remote locations for assistance in emergencies. They are one-hundredth the weight of conventional solar panels, generate 18 times more power-per-kilogram, and are made from semiconducting inks using printing processes that can be scaled in the future to large-area manufacturing.

Because they are so thin and lightweight, these solar cells can be laminated onto many different surfaces. For instance, they could be integrated onto the sails of a boat to provide power while at sea, adhered onto tents and tarps that are deployed in disaster recovery operations, or applied onto the wings of drones to extend their flying range. This lightweight solar technology can be easily integrated into built environments with minimal installation needs.

Small-area devices to evaluate process feasibility. A) Current-voltage characteristics of on-glass and on-parylene devices with evaporated top-electrode, used as controls. B) Current-voltage characteristics of on-glass and on-parylene devices with printed top-electrode. Parylene devices before and after release in (A) and (B) show similar performance, suggesting delamination does not degrade device performance. Drop in the short circuit current is ascribed to slight wrinkling of the devices in free-standing form. C) Schematic of how ultra-thin devices can be manufactured in a scalable manner, suggesting feasibility of roll-to-roll integration in future applications.

“The metrics used to evaluate a new solar cell technology are typically limited to their power conversion efficiency and their cost in dollars-per-watt. Just as important is integrability — the ease with which the new technology can be adapted. The lightweight solar fabrics enable integrability, providing impetus for the current work. We strive to accelerate solar adoption, given the present urgent need to deploy new carbon-free sources of energy,” says Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology, leader of the Organic and Nanostructured Electronics Laboratory (ONE Lab), director of MIT.nano, and senior author of a new paper.

Joining Bulović on the paper are co-lead authors Mayuran Saravanapavanantham, an electrical engineering and computer science graduate student at MIT; and Jeremiah Mwaura, a research scientist in the MIT Research Laboratory of Electronics.

Coating and Patterning the Bottom Electrode. A) Atomic force micrograph of silver nanowires in PEDOT:PSS slot-die coated onto parylene covered PET sheets, showing an RMS roughness of 11.8 nm. B) Atomic force micrograph of tin-oxide nanoparticles slot-die coated over the nanowires, showing a reduced RMS roughness of 7.7 nm. Scan dimensions of both images are 20 µm x 20 µm. C) Transmittance spectrum of coated nanowire electrode. Inset photograph shows coated PET sheet overlaid on printed text, with nanowire coating noticeable as a grey hue in comparison to the bare sheet of printed text which follows below. Sheet resistance was measured using an RCheck four-point probe. D) Optical microscope images showing the laser scribe for P1 patterning with the resulting edge defects, and the subsequent sealing of the scribe-line with a slot-die coated dielectric.

Traditional silicon solar cells are fragile, so they must be encased in glass and packaged in heavy, thick aluminum framing, which limits where and how they can be deployed. Six years ago, the ONE Lab team produced solar cells using an emerging class of thin-film materials that were so lightweight they could sit on top of a soap bubble. But these ultrathin solar cells were fabricated using complex, vacuum-based processes, which can be expensive and challenging to scale up.

In this work, they set out to develop thin-film solar cells that are entirely printable, using ink-based materials and scalable fabrication techniques. To produce the solar cells, they use nanomaterials that are in the form of a printable electronic inks. Working in the MIT.nano clean room, they coat the solar cell structure using a slot-die coater, which deposits layers of the electronic materials onto a prepared, releasable substrate that is only 3 microns thick. Using screen printing (a technique similar to how designs are added to silkscreened T-shirts), an electrode is deposited on the structure to complete the solar module.

The researchers can then peel the printed module, which is about 15 microns in thickness, off the plastic substrate, forming an ultralight solar device. But such thin, freestanding solar modules are challenging to handle and can easily tear, which would make them difficult to deploy. To solve this challenge, the MIT team searched for a lightweight, flexible, and high-strength substrate they could adhere the solar cells to. They identified fabrics as the optimal solution, as they provide mechanical resilience and flexibility with little added weight.

They found an ideal material — a composite fabric that weighs only 13 grams per square meter, commercially known as Dyneema. This fabric is made of fibers that are so strong they were used as ropes to lift the sunken cruise ship Costa Concordiafrom the bottom of the Mediterranean Sea. By adding a layer of UV-curable glue, which is only a few microns thick, they adhere the solar modules to sheets of this fabric. This forms an ultra-light and mechanically robust solar structure.

“While it might appear simpler to just print the solar cells directly on the fabric, this would limit the selection of possible fabrics or other receiving surfaces to the ones that are chemically and thermally compatible with all the processing steps needed to make the devices. Our approach decouples the solar cell manufacturing from its final integration,” Saravanapavanantham explains.

OPV Modules and Free-Standing Parylene Devices. A) Photograph of completed OPV modules on PET substrate. B) Current-voltage characteristics of control devices (PET-IMI, PET-AgNW) and parylene on PET devices before and after release from the PET carrier.

When they tested the device, the MIT researchers found it could generate 730 watts of power per kilogram when freestanding and about 370 watts-per-kilogram if deployed on the high-strength Dyneema fabric, which is about 18 times more power-per-kilogram than conventional solar cells.

“A typical rooftop solar installation in Massachusetts is about 8,000 watts. To generate that same amount of power, our fabric photovoltaics would only add about 20 kilograms (44 pounds) to the roof of a house,” he says.

They also tested the durability of their devices and found that, even after rolling and unrolling a fabric solar panel more than 500 times, the cells still retained more than 90 percent of their initial power generation capabilities. While their solar cells are far lighter and much more flexible than traditional cells, they would need to be encased in another material to protect them from the environment. The carbon-based organic material used to make the cells could be modified by interacting with moisture and oxygen in the air, which could deteriorate their performance.

“Encasing these solar cells in heavy glass, as is standard with the traditional silicon solar cells, would minimize the value of the present advancement, so the team is currently developing ultrathin packaging solutions that would only fractionally increase the weight of the present ultralight devices,” says Mwaura.

“We are working to remove as much of the non-solar-active material as possible while still retaining the form factor and performance of these ultralight and flexible solar structures. For example, we know the manufacturing process can be further streamlined by printing the releasable substrates, equivalent to the process we use to fabricate the other layers in our device. This would accelerate the translation of this technology to the market,” he adds.

High Efficiency Aqueous Solution Sprayed CIGSSe Solar Cells: Effects of Zr 4+ ‐Alloyed In 2 S 3 Buffer and K‐Alloyed CIGSSe Absorber

by Md Salahuddin Mina, SeongYeon Kim, Temujin Enkhbat, Enkhjargal Enkhbayar, JunHo Kim in Advanced Functional Materials

Clean, sustainable energy solutions are essential to meet the ever-increasing energy demands of the human population. High efficiency solar cells are promising candidates to reduce carbon emissions and achieve carbon neutrality. In this regard, solution-processed copper indium gallium sulfur diselenide solar cells (CIGSSe) solar cells have generated significant interest owing to their excellent photovoltaic properties, such as high absorption of visible light, stability, and tunable bandgap. However, large scale, practical applications are limited by a two-fold challenge.

The power conversion efficiency (PCE) of solution-processed copper indium gallium sulfur diselenide solar cells is significantly lower compared to that achieved by expensive, vacuum-based fabrication methods. Moreover, solution-based methods rely on solvents that are hazardous. To this end, researchers at Incheon National University, Korea, have developed a cost-effective, eco-friendly fabrication technique using aqueous spray deposition in air environment that does not require vacuum. This novel approach yields a relatively high PCE of over 17%.

Schematic illustration of fabrication process flow for CIGSSe (K-CIGSSe) solar cell with Zr4+ alloyed In2S3 buffer or CdS buffer. CIGSSe, K-CIGSSe and Zr4+ alloyed In2S3 are deposited by spray pyrolysis, whereas CdS is fabricated by chemical bath deposition (CBD).

Firstly, solution-based CIGSSe fabrication yields very low power conversion efficiency and often uses solvents that are not environment-friendly. Secondly, to achieve higher power conversion efficiency, fabrication methods rely on expensive vacuum environment that leads to substantial material loss. To this end, a team of researchers led by Professor JunHo Kim from Global Energy Research Center for Carbon Neutrality, Incheon National University, Korea have developed a low-cost and eco-friendly fabrication method of high efficiency CIGSSe solar cells.

In a study made available online on 4 September 2022 and subsequently published in volume 32 Issue 46 of Advanced Functional Materials on 10 November 2022, the researchers used aqueous spray deposition in an air environment and developed a CIGSSe solar cell with power conversion efficiency (PCE) larger than 17 %. “For spray solution, we used deionized water, which is eco-friendly and cheapest solvent till date,” explains Prof. Kim. Moreover, conventional solution-based fabrication processes rely on environmentally hazardous, cadmium-based buffers for the optimization of thin-film solar cells. In this novel technique, the researchers used indium sulfide-based buffer that is a cadmium free, eco-friendly alternative.

Time of flight secondary ion mass spectroscopy (TOF-SIMS) depth profiles for a) Zr00-In2S3 buffered CIGSSe, b) Zr014-In2S3 buffered CIGSSe and c) Zr120-In2S3 buffered CIGSSe films. Raman mapping (30 × 30 µm2) of d) Zr00-In2S3 buffered CIGSSe and e) Zr014-In2S3 buffered CIGSSe films and Raman point spectroscopy for α and β points.

The researchers further investigated the alloying effects of zirconium on indium sulfide buffers. Remarkably, the team found that zirconium alloying increases the electron concentration in the buffer. Moreover, this method “passivates” or reduces defect states in the CIGSSe absorber, optimizing the charge transfer between various interfaces, leading to enhanced PCE. Further, the researchers achieved even more defect passivation and higher PCE, of more than 17%, by alloying the CIGSSe absorber with potassium. The fabricated cell has an optimum bandgap for high efficiency applications such as a bottom cell or a tandem cell.

This novel technique is cost-effective and easily scalable as it does not require a vacuum environment. As Prof. Kim observes, “We carried out spray deposition in an air environment without using any high vacuum facility, which significantly reduces fabrication cost and thus makes the fabrication technique more practical and competitive in the industry sector.”

This development simultaneously improves the performance and fabrication of CIGSSe solar cells. This will revolutionize the application of these cells in integrated photovoltaic devices and vehicle integrated photovoltaic devices, and as energy sources for internet of things devices.

Intermediate-phase engineering via dimethylammonium cation additive for stable perovskite solar cells

by David P. McMeekin, Philippe Holzhey, Sebastian O. Fürer, Steven P. Harvey, Laura T. Schelhas, James M. Ball, Suhas Mahesh, Seongrok Seo, Nicholas Hawkins, Jianfeng Lu, Michael B. Johnston, Joseph J. Berry, Udo Bach, Henry J. Snaith in Nature Materials

Researchers at Oxford University and Exciton Science have demonstrated a new way to create stable perovskite solar cells, with fewer defects and the potential to finally rival silicon’s durability.

By removing the solvent dimethyl-sulfoxide and introducing dimethylammonium chloride as a crystallisation agent, the researchers were able to better control the intermediate phases of the perovskite crystallisation process, leading to thin films of greater quality, with reduced defects and enhanced stability. Large groups of up to 138 sample devices were then subjected to a rigorous accelerated ageing and testing process at high temperatures and in real-world conditions. Formamidinium-caesium perovskite solar cells created using the new synthesis process significantly outperformed the control group and demonstrated resistance to thermal, humidity and light degradation.

This is a strong step forward to matching commercial silicon’s stability and makes perovskite-silicon tandem devices a much more realistic candidate for becoming the dominant next-generation solar cell. Led by Professor Henry Snaith (Oxford University) and Professor Udo Bach (Monash University), the work has been published in the journal Nature Materials.

Oxford University PhD student Philippe Holzhey, a Marie Curie Early Stage Researcher and joint first author on the work, said: “It’s really important that people start shifting to realise there is no value in performance if it’s not a stable performance. “If the device lasts for a day or a week or something, there’s not so much value in it. It has to last for years.”

During testing, the best device operated above the T80 threshold for over 1,400 hours under simulated sunlight at 65°C. T80 is the time it takes for a solar cell to reduce to 80% of its initial efficiency, a common benchmark within the research field. Beyond 1,600 hours, the control device fabricated using the conventional dimethyl-sulfoxide approach stopped functioning, while devices fabricated with the new, improved design retained 70% of their original efficiency, under accelerated aging conditions. The same degradation study was performed on a group of devices at the very high temperature of 85°C, with the new cells again outperforming the control group. Extrapolating from the data, the researchers calculated that the new cells age by a factor of 1.7 for each 10°C increase in the temperature they are exposed to, which is close to the 2-fold increase expected of commercial silicon devices.

Impact of DMACl on the intermediate phases of FA0.83Cs0.17Pb(Br0.2I0.8)3.

Dr David McMeekin, the corresponding and joint first author on the paper, was an Australian Centre for Advanced Photovoltaics (ACAP) Postdoctoral Fellow at Monash University and is now a Marie Skłodowska-Curie Postdoctoral Fellow at Oxford University. He said: “I think what separates us from other studies is that we’ve done a lot of accelerated aging. We’ve aged the cells at 65°C and 85°C under the whole light spectrum.”

The number of devices used in the study is also significant, with many other perovskite research projects limited to just one or two prototypes.

“Most studies only show one curve without any standard deviation or any kind of statistical approach to determine if this design is more stable than the other,” David added.

The researchers hope their work will encourage a greater focus on the intermediate phase of perovskite crystallisation as an important factor in achieving greater stability and commercial viability.

Artificially synthesised in laboratory conditions, semiconductor thin films made up of perovskite compounds are far cheaper to make than silicon solar cells, with greater flexibility and a tunable band gap. They emerged unexpectedly in the last decade and have reached impressive power-conversion efficiencies of over 25%. However, too much focus has been placed on creating the most efficient perovskite solar cell, rather than resolving the fundamental problems inhibiting the material from being used in widespread commercial applications. Compared to silicon, perovskites can degrade rapidly in real world conditions, with exposure to heat and moisture causing damage and negatively impacting device performance. Solving these stability issues is the key challenge for perovskites in their quest to take on, or “boost” silicon via a tandem architecture and take their place in the commercial photovoltaics landscape.

Avoiding Fermi Level Pinning at the SnS Interface for High Open-Circuit Voltage

by Issei Suzuki, Binxiang Huang, Sakiko Kawanishi, Takahisa Omata, Andreas Klein in The Journal of Physical Chemistry

With the push towards carbon neutrality growing, and as a worrying trend of rising temperatures and natural disasters caused by global warming continues, solar cells will play a pivotal role in the world’s transition to renewable energy.

Now, a research group has laid the path for achieving higher open-circuit voltage in tin sulfide (SnS) solar cells, thus realizing their latent potential as a thin-film solar material.

(a) A schematic of the interface between the SnS single crystal/MoO3 thin film analyzed in this study. (b) A sample actually used for the photoelectron spectroscopy measurement. Several single crystals are fixed on a stainless-steel plate. (C) A schematic energy band diagram of the present interface where SnS band exhibited large bending.

Thin-film solar cells, which comprise compound semiconductors with strong light absorption, require less raw materials, making them lighter and cheaper to produce. SnS is one such thin-film solar cell material with environmentally friendly credentials, since it contains no rare or toxic elements. Yet, in recent years, researchers have begun to question this premise since, despite more than 20 years of research into them, their conversion efficiency had reached a mere 5% due to a low open-circuit voltage. The group, which was led by Assistant Professor Issei Suzuki, from Tohoku University’s Institute of Multidisciplinary Research for Advanced Materials, successfully demonstrated a SnS interface exhibiting large band bending — something necessary for obtaining a higher open-circuit voltage.

“We used photoelectron spectroscopy to analyze the electronic structure of the interface where molybdenum oxide was deposited on a SnS single crystal,” said Suzuki. “We confirmed that the interface state achieved a high open-circuit voltage.”

This is not Suzuki’s first breakthrough in SnS thin-film solar cells either. Back in December 2021, he led another group that produced the world’s first n-type SnS thin film. This enabled homojunctions to be formed in thin films.

For the current research, the group also proposed a method for fabricating interfaces suitable for SnS thin-film solar cells, including reducing the sulfur deficiency in the SnS thin films and employing a homojunction structure in their n-type and p-type layers.

“In the near future, we hope to fabricate homojunction solar cells with high conversion efficiency,” added Suzuki.

Three-Dimensional Covalent Organic Framework with scu-c Topology for Drug Delivery

by Saikat Das, Taishu Sekine, Haruna Mabuchi, Tsukasa Irie, Jin Sakai, Yu Zhao, Qianrong Fang, Yuichi Negishi in ACS Applied Materials & Interfaces

In our quest for clean energy and sustainable health solutions, advanced materials with unique, customizable properties play a crucial role. Among them, a new generation of porous solids known as three dimensional (3D) covalent organic frameworks (COFs) have generated considerable interest owing to potential applications in catalysis, separation, semiconduction, proton conduction, and biomedicine. The novelty of these materials lies in their synthesis as well as their applications. 3D COFs are porous organic materials developed from linking molecular building blocks with strong covalent bonds into crystalline, extended, net-like reticular three-dimensional structures.

However, synthesis of 3D COFs from pre-designed building units leading to net-like “reticular” arrangement of constituent parts or “network topologies” remains challenging. This is due to the shortage of 3D building units and inadequate reversibility of the linkages between the building units.

Recently, Professor Yuichi Negishi from the Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Japan, and his colleagues in the Department of Applied Chemistry, Tokyo University of Science, Dr. Saikat Das, Mr. Taishu Sekine, and Ms. Haruna Mabuchi have succeeded for the first time in creating a novel 3D COF unique networked topology. “In this study, we have succeeded for the first time in creating a 3D COF with scu-c topology (network structure) by connecting nodes of a regular plane (4-connected) with nodes of a regular prism (8-connected). This new COF, i.e., TUS-84, has a double interpenetrating structure with well-defined voids,” says Prof. Negishi.

As a part of the study, the researchers performed a condensation reaction of two organic linkers called DPTB-Me and TAPP with different symmetries, to yield 3D COF with an scu-c net-like arrangement of constituents. The team then conducted powder x-ray diffraction (PXRD) and high-resolution transmission electron microscopy (HRTEM) to analyze the crystal structure and properties of the synthesized 3D COF. The researchers also conducted structural modeling and simulation, which showed great alignment with the observed experimental features while providing further structural insights.

The researchers further demonstrated that the synthesized 3D COF has excellent hydrogen, carbon dioxide, and methane adsorption properties that reinforces its prospects in carbon capture and clean energy applications. As Prof. Negishi notes, “The development of appropriate COFs also facilitates the recovery of metal resources and noble gases, such as argon, in an energy-efficient way. This contributes to the improvement of resource and energy problems.”

The icing on the cake for this novel 3D COF is its efficiency in drug delivery applications. The team unveiled TUS-84’s drug delivery capabilities with efficient drug loading and sustained release profiles using ibuprofen, a common nonsteroidal anti-inflammatory drug. TUS-84 showed an extended drug release performance of about 35% after 5 days. This facilitates the delivery of sustained concentrations of drug over a prolonged period. As a result, dose frequency could be reduced, and more consistent control of long-lasting, chronic pain could be possible.

The findings of this study pave the way toward the development of future 3D COFs with unique topologies for applications across a wide range of fields, from medicine to environmental remediation.

Homogeneous Gold Catalysis Using Complexes Recovered from Waste Electronic Equipment

by Sean McCarthy, Oriane Desaunay, Alvin Lee Wei Jie, Maximilian Hassatzky, Andrew J. P. White, Paola Deplano, D. Christopher Braddock, Angela Serpe, James D. E. T. Wilton-Ely in ACS Sustainable Chemistry & Engineering

Researchers have used gold extracted from electronic waste as catalysts for reactions that could be applied to making medicines.

Re-using gold from electronic waste prevents it from being lost to landfill, and using this reclaimed gold for drug manufacture reduces the need to mine new materials. Current catalysts are often made of rare metals, which are extracted using expensive, energy-intensive and damaging mining processes. The method for extracting gold was developed by researchers at the University of Cagliari in Italy and the process for using the recovered gold was developed by researchers at Imperial College London.

Waste electrical and electronic equipment (WEEE) is typically sent to landfill, as separating and extracting the components requires a lot of energy and harsh chemicals, undermining its economic viability. However, WEEE contains a wealth of metals that could be used in a range of new products. Finding ways to recover and use these metals in a low-cost, low-energy and non-toxic way is therefore crucial for making our use of electronic goods more sustainable.

Lead researcher Professor James Wilton-Ely, from the Department of Chemistry at Imperial, said: “It is shocking that most of our electronic waste goes to landfill and this is the opposite of what we should be doing to curate our precious elemental resources. Our approach aims to reduce the waste already within our communities and make it a valuable resource for new catalysts, thereby also reducing our dependence on environmentally damaging mining practices.”

“We are currently paying to get rid of electronic waste, but processes like ours can help reframe this ‘waste’ as a resource. Even SIM cards, which we routinely discard, have a value and can be used to reduce reliance on mining and this approach has the potential to improve the sustainability of processes such as drug manufacture.”

Professors Angela Serpe and Paola Deplano, from the University of Cagliari, developed a low-cost way to extract gold and other valued metals from electronic waste such as printed circuit boards (PCBs), SIM cards and printer cartridges under mild conditions. This patented process involves selective steps for the sustainable leaching and recovery of base metals like nickel, then copper, silver and, finally, gold, using green and safe reagents.

However, the gold produced from this process is part of a molecular compound and so cannot be re-used again for electronics without investing a lot more energy to obtain the gold metal. Seeking a use for this compound of recovered gold, the team of Professor Wilton-Ely and his colleague, Professor Chris Braddock, investigated whether it could be applied as a catalyst in the manufacture of useful compounds, including pharmaceutical intermediates.

Catalysts are used to increase the rate of a chemical reaction while remaining unchanged and are used in most processes to produce materials. The team tested the gold compound in a number of reactions commonly used in pharmaceutical manufacture, for example for making anti-inflammatory and pain-relief drugs. They found that the gold compound performed as well, or better, than the currently used catalysts, and is also reusable, further improving its sustainability.

The researchers suggest that making it economically viable to recover gold from electronic waste could create spin-off uses for other components recovered in the process. For example, in the process, copper and nickel are also separated out, as is the plastic itself, with all these components potentially being used in new products.

Sean McCarthy, the PhD student leading the research in the lab at Imperial, said: “By weight, a computer contains far more precious metals than mined ore, providing a concentrated source of these metals in an ‘urban mine’.”

Professor Serpe said: “Research like ours aims to contribute to the cost-effective and sustainable recovery of metals by building a bridge between the supply of precious metals from scrap and industrial demand, bypassing the use of virgin raw materials.”

The teams are working to extend this approach to the recovery and re-use of the palladium content of end-of-life automotive catalytic converters. This is particularly pressing as palladium is widely used in catalysis and is even more expensive than gold.

Impacts of the large-scale use of passenger electric vehicles on public health in 30 US. metropolitan areas

by Shuai Pan, Wendi Yu, Lewis M. Fulton, Jia Jung, Yunsoo Choi, H. Oliver Gao in Renewable and Sustainable Energy Reviews

Electric cars — and their continued sales growth — are expected to have a greener, cleaner influence on air pollution and reduce human mortality in most, if not all, U.S. metropolitan areas, according to Cornell University research.

As the microscopic soot discharged from carbon-fueled cars continues to drop substantially, the research measured the potential of the large-scale use of passenger electric vehicles on air pollution and associated economic gains throughout the U.S. by 2050.

“While we enjoy the mobility that passenger vehicles provide, many of us don’t realize how bad those carbon emissions are, that come out from tailpipes, and how they’re impacting our health,” said senior author Oliver Gao, the Howard Simpson Professor of Civil and Environmental Engineering in the College of Engineering at Cornell University.

Distributions of prevented premature mortality attributable to PM2.5 reductions resulting from large-scale use of passenger electric vehicles in 2050, for several metropolitan areas in the Pacific West.

Gao and his colleagues examined data from the Environmental Protection Agency’s National Emission Inventory, the Community Multi-scale Air Quality modeling system and an associated tool, which estimates the economic value of health impacts resulting from changes in air quality — specifically ground-level fine particles (2.5 micrometers and smaller, known as PM2.5.) With fresher air, in 27 years greater Los Angeles will have 1,163 fewer premature deaths annually, corresponding to $12.61 billion in improved economic health benefits, according to the paper. Greater New York City could see 576 fewer such deaths annually and have $6.24 billion in associated economic gains and health benefits, while Chicago could have 276 fewer deaths and gain about $3 billion in financial well-being.

In California’s San Joaquin Valley, the scientists calculated there would be 260 fewer annual deaths and a $2.82 billion economic benefit, while Dallas-Fort Worth would see 186 fewer annual deaths and $2 billion in economic and health gains, to round out the top five areas.

Global sales of electric vehicles have grown steadily, the researchers said. While electric cars sold around the world was less than 1% of market share in 2016, the share grew to 2.2% by 2018. The market share globally doubled to about 4.1% in 2020 and then to 6.6% in 2021.

(a) Name of several eGRID subregions, and (b) fuel mix (%) of sources used to generate electricity. Data source: U.S. EPA Emissions and Generation Resource Integrated Database (eGRID 2020). CAMX — mainly California; NYUP — Upstate New York; NYCW — New York City and Westchester; ERCT — mainly Texas; FRCC — mainly Florida; SRMW — mainly Missouri and Illinois.

In the U.S., market share of electric passenger vehicles was 4.5% in 2021, but at the city sales level, according to the paper, passenger vehicle market shares were 22% in San Francisco, 11.9% in Los Angeles, 11.7% in Seattle and 3.4% in New York City. With carbon-fueled passenger vehicles still all around now, tailpipe emissions surround us, said Gao, a faculty fellow at the Cornell Atkinson Center for Sustainability.

“It’s not like power plants, where the stacks are usually far away,” he said. “If we fully electrify transportation, we’re not only helping defeat global climate change, but we’re also helping the regional improvement of air quality.”

The benefits of electric vehicle adoption on air quality and public health are quite clear, it is also important to accelerate the implementation of this mitigation strategy, said the paper’s lead author Shuai Pan, a former Cornell post-doctoral researcher, now at Nanjing University of Information Science and Technology (NUIST), China.

“In addition to sound policies at the national level,” he said, “the successful implementation of zero-emission vehicle goals requires commitments and actions at the regional level.”

Electrifying transportation has comprehensive advantages. “We all want to win this battle against climate change and we all want to electrify transportation,” Gao said. “I hope this research can help local decision-makers to carry out real action and policy that improve the air and gain health rewards for regional residents in many ways.”

Increasing freshwater supply to sustainably address global water security at scale

by Afeefa Rahman, Praveen Kumar, Francina Dominguez in Scientific Reports

An almost limitless supply of fresh water exists in the form of water vapor above Earth’s oceans, yet remains untapped, researchers said. A new study from the University of Illinois Urbana-Champaign is the first to suggest an investment in new infrastructure capable of harvesting oceanic water vapor as a solution to limited supplies of fresh water in various locations around the world.

The study, led by civil and environmental engineering professor and Prairie Research Institute executive director Praveen Kumar, evaluated 14 water-stressed locations across the globe for the feasibility of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water — and do so in a manner that will remain feasible in the face of continued climate change. Kumar, graduate student Afeefa Rahman and atmospheric sciences professor Francina Dominguez published their findings.

Schematic illustration of our proposed approach for capturing moisture above the ocean surface and transporting it to proximal land for improving water security.

“Water scarcity is a global problem and hits close to home here in the U.S. regarding the sinking water levels in the Colorado River basin, which affects the whole Western U.S.,” Kumar said. “However, in subtropical regions, like the Western U.S., nearby oceans are continuously evaporating water because there is enough solar radiation due to the very little cloud coverage throughout the year.”

Previous wastewater recycling, cloud seeding and desalination techniques have met only limited success, the researchers said. Though deployed in some areas across the globe, desalination plants face sustainability issues because of the brine and heavy metal-laden wastewater produced — so much so that California has recently rejected measures to add new desalination plants.

“Eventually, we will need to find a way to increase the supply of fresh water as conservation and recycled water from existing sources, albeit essential, will not be sufficient to meet human needs. We think our newly proposed method can do that at large scales,” Kumar said.

Projection of integrated moisture flux at 14 selected sites obtained from CESM2 WACCM model output. Integrated moisture flux value is in a million kg per day per m width of an atmospheric column from 10 m to 110 m above the sea level.

The researchers performed atmospheric and economic analyses of the placement of hypothetical offshore structures 210 meters in width and 100 meters in height. Through their analyses, the researchers concluded that capturing moisture over ocean surfaces is feasible for many water-stressed regions worldwide. The estimated water yield of the proposed structures could provide fresh water for large population centers in the subtropics.

One of the more robust projections of climate change is that dry regions will get drier, and wet areas will get wetter. “The current regions experiencing water scarcity will likely be even drier in the future, exacerbating the problem,” Dominguez said. “And unfortunately, people continue moving to water-limited areas, like the Southwestern U.S.” However, this projection of increasingly arid conditions favors the new ocean vapor-harvesting technology.

“The climate projections show that the oceanic vapor flux will only increase over time, providing even more fresh water supply,” Rahman said. “So, the idea we are proposing will be feasible under climate change. This provides a much needed and effective approach for adaptation to climate change, particularly to vulnerable populations living in arid and semi-arid regions of the world.”

The researchers said one of the more elegant features of this proposed solution is that it works like the natural water cycle.

“The difference is that we can guide where the evaporated water from the ocean goes,” Dominguez said. “When Praveen approached me with this idea, we both wondered why nobody had thought about it before because it seemed like such an obvious solution. But it hasn’t been done before, and I think it is because researchers are so focused on land-based solutions — but our study shows other options do, in fact, exist.”

The researchers said this study opens the door for novel infrastructure investments that can effectively address the increasing global scarcity of fresh water.

Holocene hydroclimatic variability in the tropical Pacific explained by changing ENSO diversity

by Christina Karamperidou, Pedro N. DiNezio in Nature Communications

As with many natural phenomena, scientists look to past climate to understand what may lie ahead as Earth warms. By assessing so-called ‘flavors’ of El Niño events in past climate records and model simulations, researchers have a clearer picture of El Niño patterns over the past 12,000 years and are able to more accurately project future changes and impacts of this powerful force. The study, by scientists at the University of Hawai’i at Manoa and University of Colorado Boulder.

“We used a unique set of climate model simulations that span the Holocene, the past 12,000 years, and accounted for changes in the frequency of El Niño flavors, the three preferred locations in which the peak of warming during different El Niño events occur — eastern Pacific, central Pacific, and coastal,” said Christina Karamperidou, lead author of the study and associate professor of atmospheric sciences at the UH Manoa School of Ocean and Earth Science and Technology (SOEST). “Doing this allowed us to reconcile conflicting records of past El Niño behavior.”

El Niño is the primary factor affecting variability in water temperature and trade wind strength in the Pacific. Typically, researchers look for indicators of El Niño events in ancient, preserved material such as coral skeletons, Peruvian mollusk shells or lake sediment from the tropical Andes because locked within are indicators of past temperature and rainfall across Pacific.

Observed hydroclimate impacts of El Niño-Southern Oscillation (ENSO) flavors.

“However, depending on where the samples are taken from — eastern Pacific, central Pacific, or near the South American coast — the frequency of El Niño events appears to exhibit different patterns,” said Karamperidou. “Records from the eastern Pacific show an intensification of El Niño activity from early to late Holocene, while records from the central Pacific show highly variable El Niño throughout the Holocene.”

The new set of climate model simulations developed by Karamperidou and co-author Pedro DiNezio, associate professor at the University of Colorado Boulder, are the first to allow the study of changes in the frequency of El Niño flavors during the past 12,000 years. This enabled the researchers to test a hypothesis that Karamperidou and colleagues posed in 2015 — that paleoclimate records across the Pacific could be explained by changes in El Niño flavors.

“Indeed, we showed that Eastern Pacific events have increased in frequency from early to late Holocene, while Central Pacific and Coastal events have decreased in frequency, resulting in changes in the hydroclimate in the tropical Pacific,” said Karamperidou. “Importantly, we showed that it is not only their frequency, but also the strength of their impact that changes, which is important for interpreting records of past climate.”

The relationship between El Niño-Southern Oscillation (ENSO) diversity and tropical Pacific sea-surface temperature (SST) and precipitation variability in pre-industrial control and paleoclimate model experiments.

Additionally, this is the first study into the response of coastal El Niño events to climate changes. During these events the sea surface warming is confined off the coast of South America while the conditions in the rest of the Pacific basin are normal or colder than normal.

“These coastal events have supersized impacts with severe flooding and disasters in countries like Peru and Ecuador,” said Karamperidou. “In fact, we showed in another recent paper that even though these events are not felt around the globe like the more widely known Eastern and Central Pacific events, a better understanding of the mechanisms that drive them is essential for understanding the drivers of the other two flavors, as well.”

El Niño events have significant impacts on Hawai’i’s rainfall, trade wind strength, the probability of hurricane formation and drought, and the type of El Niño event matters for these impacts.

“This information is important for water resource managers among others to better prepare for Hawai’i regional climate,” said Karamperidou. “So, it is imperative that we gain a better understanding of the mechanisms of these flavors, and also improve their representation in climate models and assess their projected changes under future climate conditions.”

This work offers new knowledge on how El Niño may respond to climate change and thus can help reduce these uncertainties in global climate models and therefore, predictions of El Niño impacts.

Traversable wormhole dynamics on a quantum processor

by Daniel Jafferis, Alexander Zlokapa, Joseph D. Lykken, David K. Kolchmeyer, Samantha I. Davis, Nikolai Lauk, Hartmut Neven, Maria Spiropulu in Nature

Nearly 10 percent of today’s electricity in the United States comes from wind power. The renewable energy source benefits climate, air quality, and public health by displacing emissions of greenhouse gases and air pollutants that would otherwise be produced by fossil-fuel-based power plants.

A new MIT study finds that the health benefits associated with wind power could more than quadruple if operators prioritized turning down output from the most polluting fossil-fuel-based power plants when energy from wind is available. In the study researchers analyzed the hourly activity of wind turbines, as well as the reported emissions from every fossil-fuel-based power plant in the country, between the years 2011 and 2017. They traced emissions across the country and mapped the pollutants to affected demographic populations. They then calculated the regional air quality and associated health costs to each community.

The researchers found that in 2014, wind power that was associated with state-level policies improved air quality overall, resulting in $2 billion in health benefits across the country. However, only roughly 30 percent of these health benefits reached disadvantaged communities. The team further found that if the electricity industry were to reduce the output of the most polluting fossil-fuel-based power plants, rather than the most cost-saving plants, in times of wind-generated power, the overall health benefits could quadruple to $8.4 billion nationwide. However, the results would have a similar demographic breakdown.

“We found that prioritizing health is a great way to maximize benefits in a widespread way across the U.S., which is a very positive thing. But it suggests it’s not going to address disparities,” says study co-author Noelle Selin, a professor in the Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences at MIT. “In order to address air pollution disparities, you can’t just focus on the electricity sector or renewables and count on the overall air pollution benefits addressing these real and persistent racial and ethnic disparities. You’ll need to look at other air pollution sources, as well as the underlying systemic factors that determine where plants are sited and where people live.”

Selin’s co-authors are lead author and former MIT graduate student Minghao Qiu PhD ’21, now at Stanford University, and Corwin Zigler at the University of Texas at Austin.

Learning a traversable wormhole Hamiltonian from the SYK model.

In their new study, the team looked for patterns between periods of wind power generation and the activity of fossil-fuel-based power plants, to see how regional electricity markets adjusted the output of power plants in response to influxes of renewable energy.

“One of the technical challenges, and the contribution of this work, is trying to identify which are the power plants that respond to this increasing wind power,” Qiu notes.

To do so, the researchers compared two historical datasets from the period between 2011 and 2017: an hour-by-hour record of energy output of wind turbines across the country, and a detailed record of emissions measurements from every fossil-fuel-based power plant in the U.S. The datasets covered each of seven major regional electricity markets, each market providing energy to one or multiple states.

“California and New York are each their own market, whereas the New England market covers around seven states, and the Midwest covers more,” Qiu explains. “We also cover about 95 percent of all the wind power in the U.S.”

In general, they observed that, in times when wind power was available, markets adjusted by essentially scaling back the power output of natural gas and sub-bituminous coal-fired power plants. They noted that the plants that were turned down were likely chosen for cost-saving reasons, as certain plants were less costly to turn down than others.

The team then used a sophisticated atmospheric chemistry model to simulate the wind patterns and chemical transport of emissions across the country, and determined where and at what concentrations the emissions generated fine particulates and ozone — two pollutants that are known to damage air quality and human health. Finally, the researchers mapped the general demographic populations across the country, based on U.S. census data, and applied a standard epidemiological approach to calculate a population’s health cost as a result of their pollution exposure.

This analysis revealed that, in the year 2014, a general cost-saving approach to displacing fossil-fuel-based energy in times of wind energy resulted in $2 billion in health benefits, or savings, across the country. A smaller share of these benefits went to disadvantaged populations, such as minority and low-income communities, though this disparity varied by state.

“It’s a more complex story than we initially thought,” Qiu says. “Certain population groups are exposed to a higher level of air pollution, and those would be low-income people and racial minority groups. What we see is, developing wind power could reduce this gap in certain states but further increase it in other states, depending on which fossil-fuel plants are displaced.”

Observation of traversable wormhole dynamics.

The researchers then examined how the pattern of emissions and the associated health benefits would change if they prioritized turning down different fossil-fuel-based plants in times of wind-generated power. They tweaked the emissions data to reflect several alternative scenarios: one in which the most health-damaging, polluting power plants are turned down first; and two other scenarios in which plants producing the most sulfur dioxide and carbon dioxide respectively, are first to reduce their output.

They found that while each scenario increased health benefits overall, and the first scenario in particular could quadruple health benefits, the original disparity persisted: Minority and low-income populations still experienced smaller health benefits than more well-off communities.

“We got to the end of the road and said, there’s no way we can address this disparity by being smarter in deciding which plants to displace,” Selin says.

“One of the things that makes me optimistic about this area is, there’s a lot more attention to environmental justice and equity issues,” Selin concludes. “Our role is to figure out the strategies that are most impactful in addressing those challenges.”

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