Scientists develop deep-blue LEDs expected to greatly enhance general lighting

A Rutgers-led team pioneers the discovery of an eco-friendly, ultra-bright LED material

Rutgers University

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Hybrid copper iodide crystals emitting deep-blue light are being developed by scientists in a Rutgers laboratory. 

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Credit: Kun Zhu/Jing Li Lab/Rutgers University

A Rutgers-led team of scientists has developed an eco-friendly, very stable, ultra-bright material and used it to generate deep-blue light (emission at ~450 nm) in a light-emitting diode (LED), an energy-efficient device at the heart of all major lighting systems.

The new copper-iodide hybrid emitter materials are expected to contribute to the advancement of blue LED technologies because of their excellent qualities, according to the scientists who pioneered the discovery. The process that produces the material is described in the science journal Nature.

“Deep-blue LEDs are at the heart of today’s energy-efficient lighting technologies,” said Jing Li, a Distinguished Professor and Board of Governors Professor of Chemistry and Chemical Biology in the Department of Chemistry and Chemical Biology in the School of Arts and Sciences who leads the study. “However, existing options often present issues with stability, scalability, cost, efficiency or environmental concerns due to the use of toxic components. This new copper-iodide hybrid offers a compelling solution, leveraging its nontoxicity, robustness and high performance.”

LEDs are lighting devices that use special materials called semiconductors to turn electricity into light in an efficient and durable way. Blue LEDS were discovered in the early 1990s and earned their discoverers the 2014 Nobel Prize in physics.

Blue LEDs are particularly important because they are used to create white light and are essential for general lighting applications.

Li and her colleagues at Rutgers collaborated with scientists at Brookhaven National Laboratory and four other research teams representing national and international institutions in the effort to work on new materials that would improve upon existing blue LEDs.

The researchers involved in the study found a way to make blue LEDs more efficient and sustainable by using a new type of hybrid material: a combination of copper iodide with organic molecules.

“We wanted to create new kind of materials that give very bright deep-blue light and use them to fabricate LEDs at lower cost than current blue LEDs,” Li said.

The new hybrid copper-iodide semiconductor offers a number of advantages over some other materials used in LEDs, scientists said. Lead-halide perovskites, while cost effective, contain lead, which is toxic to humans, as well as have issues with stability, due to their sensitivity to moisture and oxygen. Organic LEDs (OLEDs) are flexible and potentially efficient but may lack structural and spectral stability, meaning they can degrade quickly and lose their color quality over time. Colloidal quantum dots perform well mainly in green and lower-energy LEDs and are often cadmium-based, which may raise toxicity concerns. Phosphorescent organic emitters may be costly and complex to synthesize.

“The new material provides an eco-friendly and stable alternative to what currently exists, addressing some of these issues and may potentially advance LED technology,” Li said.

The hybrid copper-iodide material possesses favorable qualities such as a very high photoluminescence quantum yield of about 99.6%, meaning it converts nearly all the photoenergy it receives into blue light. Blue LEDs made from this material have reached a maximum external quantum efficiency (the ratio between the number of emitted photons and number of injected electrons) of 12.6%, among the highest achieved so far for solution-processed deep-blue LEDs.

Not only are these LEDs bright, they also last longer compared with many others. Under normal conditions, they have an operational half-lifetime of about 204 hours, meaning they can keep shining for a good amount of time before their brightness starts to fade. In addition, the material works well in larger-scale applications. The researchers successfully created a larger device that maintains high efficiency, showing that this material has potential to be used in real-world applications.

The secret to the material’s impressive performance lies in an innovative technique developed by the scientists called dual interfacial hydrogen-bond passivation. The manufacturing technique significantly boosts the performance of the LEDs four-fold.

“Our processing method minimizes defects that can impede the movement of electric charges at the interface of these hybrid materials,” said Kun Zhu, a former graduate student and postdoctoral associate at Rutgers who is now at the Max Planck Institute in Germany and is the paper’s first author. “This approach could be a versatile strategy for generating high-performance LEDs.”

If the LED can be imagined as a sandwich with different layers, each layer has a specific job, such as emitting light or transporting electrons and holes. Sometimes, the emissive layer doesn't interact perfectly with its interface layers, which can reduce efficiency or shorten lifespan. The technique eliminates such problems by forming hydrogen bonds between the layers to create better connections.

“Overall, this type of new material is paving the way for better, brighter and longer-lasting LEDs,” Li said.

Other Rutgers scientists contributing to the study included Deirdre O’Carroll, associate professor, and Nasir Javed, doctoral student, of the Department of Chemistry and Chemical Biology and Department of Materials Science and Engineering; and Sylvie Rangan, assistant research professor, and Leila Kasaei, postdoctoral research associate, of the Department of Physics and Astronomy.

The research was funded by the U.S. Department of Energy.

Explore more of the ways Rutgers research is shaping the future.

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Journal

Nature

DOI

10.1038/s41586-025-09257-8 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Dual interfacial H-bonding-enhanced deepblue hybrid copper–iodide

Article Publication Date

16-Jul-2025

Study suggests natural areas may acquire too little nitrogen to repair climate

Oregon State University

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Red alder is a nitrogen-fixing plant species. Photo by Steven Perakis.

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Credit: Red alder is a nitrogen-fixing plant species. Photo by Steven Perakis.

CORVALLIS, Ore. – A new study indicates that forests, prairies and other natural areas around the globe acquire less nitrogen than previously estimated.

The findings have climate implications as plants need the element to remove carbon dioxide from the atmosphere.

Published today in Nature, the data analysis of biological nitrogen fixation also shows a rise in agricultural nitrogen fixation that may be contributing to the degradation of land, air and water quality.

Researchers led by Carla Reis Ely, a postdoctoral scholar in the Oregon State University College of Forestry during the study, found that estimates of nitrogen fixation had been skewed by sampling bias: Field measurements of nitrogen fixation in natural areas had been taken in places where nitrogen-fixing organisms were 17 times more prevalent than they are worldwide.

Nitrogen makes up more than three-quarters of the Earth’s atmosphere (most of the rest is oxygen) and is essential to a range of life systems, even though most organisms are unable to use it directly.

Nitrogen-fixing bacteria convert nitrogen gas, N2, in the air into forms such as ammonia that plants can use to grow, stay healthy and reproduce. They need nitrogen to make proteins and chlorophyll, the green pigment in leaves that enables photosynthesis, through which they use atmospheric carbon dioxide to produce their food.

“In natural ecosystems, nitrogen fixation improves soil fertility and supports plant growth, thereby increasing carbon storage,” said Reis Ely, who led an international team of 24 scientists on the study. “However, our new estimate of natural nitrogen fixation, based on improved scientific understanding, suggests less new nitrogen enters natural ecosystems.”

One implication of this finding is that these ecosystems may take up less carbon dioxide than scientists had thought previously, she said. That means natural ecosystems could have a lower capacity to store carbon and mitigate climate change.

Meanwhile, the rise in agricultural nitrogen fixation, through the planting of legumes such as soybeans and alfalfa that host nitrogen-fixing bacteria, is both a positive and a negative, she said. Nitrogen fixation is essential for producing food for a growing global population and is generally more environmentally sustainable than synthetic nitrogen fertilizers, but food waste in the production and consumption chain is a big contributor to nitrogen pollution.

“Using nitrogen-fixing crops in rotation can support long-term soil health and reduce environmental damage from chemical fertilizers,” she said. “But too much nitrogen can throw off the overall balance of nutrients in the soil, and excess nitrogen can leach into groundwater or run off into lakes and streams, causing algae blooms and harming aquatic life.”

In addition, surplus nitrogen can become nitrous oxide, a potent greenhouse gas, and high nitrogen levels can favor fast-growing invasive plants that squeeze out native species and reduce biodiversity.

“High agricultural nitrogen fixation is a complex issue,” said Reis Ely, now a scientist with the Oak Ridge Institute for Science and Education. “We do benefit from it, but along with applications of synthetic nitrogen fertilizer, it contributes to nitrogen pollution and climate change. Measuring and monitoring biological nitrogen fixation need to be ongoing to help us ensure we have all the nitrogen in the ground that we need without it becoming too much of a good thing.”

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Journal

Nature

DOI

10.1038/s41586-025-09201-w 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Global terrestrial nitrogen fixation and its modification by agriculture

Article Publication Date

16-Jul-2025

Nitrogen may limit natural climate solutions

Global inventory reveals nitrogen is in shorter supply than previously thought in natural areas, which could limit carbon storage in plants and soils.

Cary Institute of Ecosystem Studies

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Global biological nitrogen fixation - Infographic 

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Credit: Cary Institute of Ecosystem Studies / Leslie Tumblety

Forests, grasslands, and other natural areas around the world have access to about a quarter less nitrogen than previously estimated, according to a new study published today in Nature. Coauthored by Sarah Batterman, an ecologist at Cary Institute of Ecosystem Studies, findings have implications for natural climate solutions, as nitrogen is essential to plant growth and thus the removal of carbon from the atmosphere.

“Outside of some tropical forests and drylands, we found that the amount of nitrogen available to plants in many natural areas has been overestimated,” said Batterman, “Our results suggest there are nitrogen constraints on the terrestrial carbon sink in a range of biomes, including prairies and temperate forests.”

The study focused on nitrogen made available to plants through biological nitrogen fixation. In this process microbes — often living symbiotically with plants — transform nitrogen gas from the air into a form that plants can use to fuel growth and development. For instance, nitrogen is a crucial component of chlorophyll, the green pigment that allows plants to convert carbon dioxide into plant growth via photosynthesis. This carbon is then stored in wood, leaves, roots, and soils. 

Led by Carla Reis Ely of the Oak Ridge Institute for Science and Education, an international team of scientists quantified the global distribution and magnitude of land-based biological nitrogen fixation in both natural and agricultural biomes. They found that previous estimates of nitrogen fixation had been skewed by sampling bias. Field measurements of nitrogen fixation were often taken in natural areas where nitrogen-fixing organisms were on average 17 times more prevalent than they are worldwide, leading to an overestimation of nitrogen availability.

Whereas much of the data was historically based in tropical forests, the new study includes biological nitrogen fixation estimates from previously underrepresented niches — including shrubs, herbs, mosses, dead wood, and more — helping to identify nitrogen hotspots and deserts. 

“By building the most extensive dataset of biological nitrogen fixation rates on land, and developing a new and biologically realistic algorithm for scaling up from field measurements,” Batterman explained, “we calculated that the amount of nitrogen fixation by microbes in natural terrestrial ecosystems is approximately 25 million tons lower each year than previously estimated.” The missing nitrogen is equivalent to about 113 fully loaded cargo container ships.

Having more accurate biological nitrogen fixation rates allows for vast improvements in the models that are used to predict how much carbon dioxide the land system takes up, and how it will be affected by climate change, Batterman added.

The analysis also revealed a rise in biological nitrogen fixation in agricultural systems that may be contributing to the degradation of land, air, and water quality. Nitrogen-fixing crops such as soybeans and alfalfa support soil health and help produce food for a growing global population, but in excess, nitrogen can be harmful. The team estimated that agricultural crops alone (not including chemical fertilizers) have increased terrestrial biological nitrogen fixation by 64% relative to pre-industrial rates. 

“Excess nitrogen can leach into groundwater or runoff into lakes and streams, causing algae blooms and harming aquatic life,” said Reis Ely, who led the study while she was a postdoctoral scholar at Oregon State University.

In addition, surplus nitrogen can become nitrous oxide, a potent greenhouse gas, and high nitrogen levels can favor fast-growing invasive plants that squeeze out native species and reduce biodiversity.

The study “helps us understand the degree to which we have modified the nitrogen cycle, exceeding the safe operating space for humanity when it comes to nitrogen,” said Batterman.

Reis Ely called for more consistent measuring and monitoring of biological nitrogen fixation, “to help us ensure we have all the nitrogen in the ground that we need without it becoming too much of a good thing.” 

For her leadership on the paper, Reis Ely has earned the Gene E. Likens Junior Scientist Outstanding Publication Award from the Ecological Society of America’s Biogeosciences Section. Named after Cary founder Gene Likens, who co-discovered acid rain, the award promotes early-career scientists and highlights exceptional work in the field.

Funding

This research was supported in part by an appointment to the US Geological Survey (USGS) Research Participation Program administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Departments of Energy (DOE) and Interior (DOI) under DOE contract number DE-SC0014664. The paper is a contribution from a working group on biological nitrogen fixation supported by the USGS John Wesley Powell Center for Analysis and Synthesis. 

Authors

• Carla R. Reis Ely, Oregon State University and Oak Ridge Institute for Science and Education

• Steven S. Perakis, US Geological Survey

• Cory C. Cleveland, University of Montana 

• Duncan N. L. Menge, Columbia University

• Sasha C. Reed, US Geological Survey 

• Benton N. Taylor, Harvard University 

• Sarah A. Batterman, Cary Institute of Ecosystem Studies, University of Leeds, and Smithsonian Tropical Research Institute

• Christopher M. Clark, US Environmental Protection Agency

• Timothy E. Crews, The Land Institute

• Katherine A. Dynarski, University of Montana

• Maga Gei, Association for Tropical Biology and Conservation

• Michael J. Gundale, Swedish University of Agricultural Sciences

• David F. Herridge, University of New England, Australia

• Sarah E. Jovan, USDA Forest Service

• Sian Kou-Giesbrecht, Dalhousie University

• Mark B. Peoples, CSIRO Agriculture and Food

• Johannes Piipponen, Aalto University

• Emilio Rodríguez-Caballero, Universidad de Almería and Max Planck Institute for Chemistry

• Verity G. Salmon, Oak Ridge National Laboratory

• Fiona M. Soper, McGill University

• Anika P. Staccone, Earthshot Labs

• Bettina Weber, University of Graz and Max Planck Institute for Chemistry

• Christopher A. Williams, Clark University

• Nina Wurzburger, University of Georgia

 

Cary Institute of Ecosystem Studies is an independent nonprofit center for environmental research. Since 1983, our scientists have been investigating the complex interactions that govern the natural world and the impacts of climate change on these systems. Our findings lead to more effective resource management, policy actions, and environmental literacy. Staff are global experts in the ecology of: cities, disease, forests, and freshwater.

Nitrogen-fixing lupines (with purple flowers) were introduced in Iceland to restore soils, but have taken over the vegetation in some areas. 

Nitrogen-fixing nodules contain microorganisms that change nitrogen gas (N2) into forms that plants can use to grow, reproduce, and absorb carbon dioxide. 

Credit

Cary Institute of Ecosystem Studies / Sarah Batterman

Rates of biological nitrogen fixation in natural (top) and agricultural ecosystems. Warmer colors indicate higher production rate of nitrogen that plants can use to grow and absorb carbon dioxide. 

Credi

Reis Ely et al./Nature 2025

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Journal

Nature

DOI

10.1038/s41586-025-09201-w 

Article Title

Global terrestrial nitrogen fixation and its modification by agriculture

Article Publication Date

16-Jul-2025

 

Study: Transgender Americans fear losing medical care

New research reveals increased risk of suicide and do-it-yourself hormone use if identity-affirming medical access is denied

University of Vermont

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Teresa Graziano is a professor of nursing at the University of Vermont.  

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Credit: Photo courtesy of Teresa Graziano

Gender-diverse individuals not only fear losing their access to gender-affirming care but may resort to self-harm or questionable alternatives if it disappears, according to new research from the University of Vermont (UVM) published July 16 in JAMA Network Open.

Teresa Graziano, a professor of nursing at UVM and lead author of the study, surveyed 489 gender-diverse Americans 18 and over about their expectations for medical care after President Donald Trump campaigned on rolling back protections for the nearly two million trans, nonbinary, and intersex individuals in the United States. Gender-affirming care (GAC) includes surgical procedures, hormonal treatments, or mental health services for individuals with gender dysphoria. The findings of Graziano’s study were stark: Every respondent thought they would lose access to care, nearly a third reported they would consider some form of do-it-yourself hormone therapy, and over 21 percent expressed either active or passive suicidal ideation.

“This is a population that already feels that their access to care is constantly under threat, and so when you have somebody going into power that is campaigning on removing their access to care they believe it,” says Graziano, a registered nurse who uses they/them pronouns. “It was startling.”

The study closed on Inauguration Day, January 20. Since then, a series of Executive Orders has been issued preventing the U.S. government from recognizing more than two sexes—male and female—and directing federal agencies and programs to work towards banning  gender-affirming care for trans youth. Additional orders include proposals to prohibit gender-affirming care as an essential benefit for patients on health insurance plans offered under the Affordable Care Act. However, those orders are currently tied up in the courts. In June, the Supreme Court upheld Tennessee’s ban on gender-affirming care for minors, opening the door for other states to do the same.

“I want be clear that there is no federal ban on care right now,” Graziano says, adding that most providers are still caring for patients.

Graziano’s research aims to improve outcomes and patient care for gender diverse populations—groups that historically have higher rates of suicide, anxiety, and depression than the general population. As they combed the data, Graziano became concerned at the terms people were using when asked what, if anything, they would do if gender-affirming care was banned. While some participants talked about suicide, others spoke more passively about it.

“They are saying that there is not a life worth living without being their authentic self,” Graziano says.

They point to the real dangers that persist if access to gender-affirming care is denied. People may turn to extreme measures such as using do-it-yourself hormone therapy that can jeopardize their health.

“This can quite literally be people's synthesizing hormones at home using kits that you can purchase online,” Graziano says. “It may also the use of the gray or black market especially for things like testosterone which are FDA regulated and are controlled substances.”

Patients on hormones require careful blood monitoring to ensure they are taking the proper dosage. Osteoporosis can develop when hormone levels are outside normal levels, Graziano explains.

A ban on gender-affirming care could damage the trust between patients and their healthcare providers. If patients acquire hormones through questionable means, they may not trust their doctors enough to admit it.

“The hope is that yes, they [will] because medicine and the legal system has been very good about keeping it fairly separate when things like that happen,” Graziano says.

Should a ban on gender-affirming care come into effect, Graziano advocates that clinicians treat gender-diverse individuals using a harm reduction approach—a practice generally used for individuals with substance abuse disorders.

“We should not be judging this community for making do with what they have,” Graziano says. “We just need to partner with them to make sure they are as healthy as possible as they get through what they need to get through. And I think that as we continue having these conversations about whether or not this care should be banned, we also need to think about how this is going to affect the lives of very real human beings whose mental health is reliant upon their access to being their true self.”

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The contents of the study and research letter are embargoed until 11am EST on July 16, 2025.

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Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.20808 

Method of Research

Survey

Subject of Research

People

Article Title

Access to Gender Affirming Care and Alternatives to that Care Among Transgender Adults

Article Publication Date

16-Jul-2025