American College of Chest Physicians advances sustainability with solar panel installation at Glenview headquarters
American College of Chest Physicians
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As part of its ongoing dedication to social responsibility, the CHEST installed a solar panel system at its Glenview, Illinois headquarters.
view moreCredit: American College of Chest Physicians (CHEST)
Glenview, Illinois – As part of its ongoing dedication to social responsibility, the American College of Chest Physicians (CHEST) installed a solar panel system at its Glenview, Illinois headquarters.
The solar installation marks a significant step forward in CHEST’s efforts to reduce its carbon footprint, aligning with its mission to promote lung health and support healthier communities. By reducing its reliance on fossil fuels, CHEST is directly addressing one of the root causes of air pollution, an environmental determinant that impacts respiratory health.
“At CHEST, we understand that the health of patients begins with the air they breathe,” said Robert A. Musacchio, PhD, CEO of CHEST. “The CHEST solar panel installation is a meaningful action that benefits not just the climate, but the daily lives of people in the Glenview community, and we are proud to lead by example.”
This investment in renewable energy builds on CHEST’s longstanding environmental efforts. In 2014, the organization’s headquarters earned LEED® Silver certification for its sustainable design, energy efficiency, and indoor environmental quality. The addition of solar energy further enhances this foundation, demonstrating CHEST’s leadership in the intersection of health and sustainability.
“All those working in the pulmonary field see firsthand the toll that pollution takes on respiratory health,” said John Howington, MD, MBA, FCCP, President of CHEST. “By investing in solar energy, CHEST is taking measurable steps toward reducing our environmental impact. It’s not just about sustainability; it’s about a healthier future.”
Beyond the health impact, the solar initiative reflects CHEST’s dedication to being a responsible neighbor in Glenview. By reducing carbon emissions and drawing on clean, renewable energy sources, CHEST is contributing to a more sustainable and resilient future for the entire region.
As CHEST continues to grow, leadership believes that social accountability must remain part of the mission of improving lung health worldwide.
About the American College of Chest Physicians
The American College of Chest Physicians® (CHEST) is the global leader in the prevention, diagnosis, and treatment of chest diseases. Its mission is to champion advanced clinical practice, education, communication, and research in chest medicine. It serves as an essential connection to clinical knowledge and resources for its 18,000+ members from around the world who provide patient care in pulmonary, critical care, and sleep medicine. For information about the American College of Chest Physicians and its family of journals, including the flagship journal CHEST®, visit chestnet.org.
Fixing solar’s weak spot: Why a tiny defect could be a big problem for perovskite cells
A collaboration between a team led by RASEI Fellow Mike McGehee at the University of Colorado Boulder and scientists at the National Renewable Energy Laboratory (NREL), just published in the scientific journal Joule, provides evidence to help solve one of the key hurdles to large-scale manufacture of next-generation perovskite solar cells.
Imagine you have a series of hoses connected end-to-end to water your garden. The water flows from the faucet, through each hose, and out the last nozzle. When every hose is getting enough water, the flow is strong and steady. This is like how a string of solar cells works on a solar panel; the sun’s energy makes electrons (the “water”) that flow through each cell, creating electricity.
But what happens if a single section of the hose gets kinked? The water can’t flow through it anymore, but there is still a lot of pressure coming from the faucet. The pressure will build up and eventually burst the weak spot in the kinked section. This is analogous to what happens when a section of the solar panel is shaded --- the cell becomes ‘kinked’. When just one part of a panel is shaded, the unshaded cells still generate electricity and “force” current backward through the non-producing shaded cell. This is known as reverse bias, and it can cause the shaded cell to permanently degrade and fail.
For conventional silicon-based solar cells, reverse bias is a known problem and engineers have developed a solution: a bypass diode. You can think of this as a small side-channel that allows the water to flow around the kinked hose, keeping the rest of the system running smoothly without building up damaging pressure.
However, the bypass diode solution doesn’t work for perovskite-based solar cells, a leading candidate for the next generation of more efficient and more affordable solar cells, because they are often too “weak”. One of the key pieces in the puzzle to solving this reverse bias problem in perovskite solar cells is understanding how the cell degrades when under reverse bias, and that is the focus of this research collaboration.
The McGehee group has a long history of success in creating and optimizing perovskite solar cells. Beginning in 2018, their focus shifted to a critical challenge: what happens when these cells are in the shade? Many researchers had already observed that even a small amount of reverse bias caused the materials to heat up and "melt," leading to rapid and permanent degradation of the perovskite.1
While these observations were widely accepted, the exact reason for the degradation was a mystery and a subject of much debate. "These are complex systems, and it can be very hard to untangle what is going on," explained Ryan DeCrescent, one of the study's lead researchers. This is where the McGehee group's work came in—they set out to find the specific mechanism behind this destructive behavior.
The perovskite layer is formed through an approach called solution processing. Solution processing is kind of like making a pancake, you make your batter and when you pour it onto a hot griddle several things happen: the water evaporates, the solids set, the thickness is determined by how much you add, and you often get gaps, or holes in your pancake. In these devices, the perovskite ingredients are put into a solvent. The solvent is then dropped onto the earlier layers of the device and warmed up, whereby the solvent evaporates and a film is formed, but often with defects, or gaps. Defects and pinholes are easily formed in such films. This is a particular issue for perovskites, since the precursor solution has low viscosity and during the heating stage defect formation is common.
To better understand the impact of these defects on the performance of the solar cells under reverse bias you need to take a really good look at them. Central to this work is a suite of tools that enabled exceptional examination of the perovskite layer. “A large part of this work was really setting ourselves up to look very carefully at these surfaces” said DeCrescent. Four main techniques were employed to better understand the defects: Electroluminescence (EL) imaging with a high-resolution camera, Scanning Electron Microscopy (SEM), Laser-Scanning Confocal Microscopy (LSCM) and Video Thermography. The strategy was to compare ‘before, during, and after’ pictures of devices that had been exposed to reverse bias. The high-resolution camera showed that “weak spots” in the device were the origin of degradation. To better understand “perfect” device behavior and efficiently scan a large number of samples (~100), the team setup a large number of very small devices, creating thin films with an area of just 0.032 mm2. To put that in perspective, each device was about the width of two human hairs. The small size of these devices meant that it was possible to create devices that were defect-free, since it is hard to create defect-free films on a larger scale. Through this combination of a large sample size, and advanced imaging, the team was able to rapidly explore many different types of defects.
This approach of using advanced imaging proved to be an incredibly effective way not only to identify the defects but also to understand exactly what happens to them. "Video thermography and electroluminescence imaging are really powerful techniques for such devices; for example, defects that are sometimes difficult to spot really stand out using these approaches," explained Ryan. Using the thermography technique the defects glow brightly, and in the electroluminescence technique the defects show as dark. Using these techniques in combination provided a very reliable and effective way of mapping the defects. The techniques clearly revealed where the degradation was occurring.
The team’s evidence strongly supports the argument that defects, like pinholes and thin spots in the perovskite layer, are the precise locations where reverse-bias breakdown begins. The thermography images showed that these sites are where the material rapidly heats up and melts, essentially shorting between the two contact layers. In contrast, defect-free devices showed remarkable stability, surviving hours of reverse bias without any significant degradation.
This level of detailed understanding is crucial for the future of this technology. The team's research provides a clear path forward for scientists and engineers: to develop more robust and stable perovskite solar cells, they must prioritize making pinhole-free films and using more robust contact layers to prevent this kind of abrupt and permanent thermal damage.
This work represents a critical step in the journey toward commercializing perovskite solar cells. It highlights the fact that detail-driven, rigorous scientific approaches are needed to understand complex problems. With this knowledge in hand, scientists can now engineer devices that are designed for longevity, ensuring these promising materials can fulfill their potential.
Journal
Joule
DOI
Recent advances in exciton-polariton in perovskite
Along with being superior in solar cell applications, perovskites are also gaining popularity as an ideal semiconductor material for investigating light-matter interaction in the strong coupling regime.
Opto-Electronic Journals Group
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Fig 1. Schematic representation of strong coupling between a cavity mode and an exciton in a semiconductor leading to energy spilt into two branches as shown in energy diagram and absorption spectrum.
view moreCredit: Khalil As’ham, Andrey E. Miroshnichenko
Perovskites, a class of materials known for their stellar performance in solar cells, are now making waves in the world of advanced optics. These versatile semiconductors can capture and emit light in ways that traditional materials like silicon cannot, offering a cheaper and simpler way to create cutting-edge technologies. This review explores a fascinating phenomenon called exciton-polaritons, hybrid particles formed when light and matter merge so strongly that they act as one. This merging, or “strong coupling,” happens when light bounces inside tiny cavities, interacting intensely with excitons (pairs of electrons and holes) in perovskites. The result is a unique state that blends the speed of light with the interactivity of matter, opening doors to new devices like efficient lasers and quantum computers.
What makes perovskites special is their ability to achieve this strong coupling at room temperature, unlike other materials that need extreme cooling or costly production. Their large binding energies and tunable colors make them ideal for creating polaritons that work across a wide range of light wavelengths. The motivation behind this research is to harness these properties to build practical, energy-saving devices that could transform industries, from telecommunications to renewable energy. By reviewing recent breakthroughs, the team aims to show how perovskites can bridge the gap between lab discoveries and real-world applications, making advanced photonics more accessible. The significance lies in creating technologies that are not only powerful but also affordable, potentially revolutionizing how we manipulate light for everything from displays to sensors. This work highlights why perovskites are becoming a go-to material for scientists eager to push the boundaries of light-matter interactions.
About the authors:
Led by Professor Andrey E. Miroshnichenko and Dr. Haroldo Hattori from the University of New South Wales, Canberra, this review comprehensively discusses recent progress in generating and utilizing exciton-polaritons in perovskite materials. Initially, the article introduces fundamental concepts of strong coupling, describing how intense interactions between photons and excitons in perovskites create polaritons, enabling phenomena such as ultra-efficient photoluminescence. Crucially, perovskite semiconductors facilitate these interactions at room temperature through relatively straightforward methods, in contrast to conventional semiconductor materials that necessitate sophisticated processing and extreme cooling.
The review highlights three principal approaches for realizing strong coupling. First, mirror-based microcavities trap photons between reflective surfaces, significantly enhancing interaction strength with embedded perovskite materials. Experiments using this approach have achieved polariton lasing and condensation, where coherent polariton states form efficiently at room temperature, leading to low-threshold laser applications. For instance, perovskite nanoplatelets sandwiched between mirrors successfully demonstrated polariton condensation, exemplifying practical device potential. Secondly, plasmonic nanostructures localize electromagnetic fields into subwavelength volumes, dramatically intensifying exciton-photon interactions. Studies involving perovskite-coated metal gratings and perovskite nanowires placed on metal substrates have reported exceptionally high coupling strengths, ideal for developing ultra-compact optical devices such as switches and sensors. Thirdly, dielectric metasurfaces, comprising precisely patterned surfaces, offer unique control over photonic modes, resulting in tailored polaritonic dispersions. Such structures have enabled the realization of exotic emission patterns and significantly boosted Rabi splitting values, paving the way for sophisticated optical circuitry and advanced optoelectronic integration.
The review emphasizes the practical implications of these advances, including energy-efficient LEDs, low-power polariton lasers, and potential quantum computing applications. Nevertheless, persistent challenges such as long-term material stability and scalability for mass production are discussed, highlighting ongoing research efforts aimed at overcoming these hurdles through enhanced materials engineering and optimized cavity designs. By integrating theoretical models with experimental demonstrations, the review provides an informative overview of perovskites' transformative potential in modern photonics, guiding future developments toward robust and scalable photonic technologies.
Conclusion:
Looking forward, perovskite-based exciton-polaritons have significant potential for next-generation optoelectronic devices, including low-threshold polariton lasers, highly efficient LEDs, and integrated components for quantum computing applications. However, critical challenges remain, particularly concerning the long-term stability of perovskite materials and scalability for practical device manufacturing. Addressing these issues requires further advancements in material science, cavity optimization, and fabrication techniques. Future research directions are likely to involve the development of hybrid structures that integrate perovskites with plasmonic and photonic lattices, exploitation of quantum effects for enhanced functionality, and exploration of novel polaritonic phenomena achievable at room temperature.
About the Research Group:
The research group at the University of New South Wales at Canberra, led by Professor Andrey E. Miroshnichenko and Dr. Haroldo Hattori, focuses on pioneering research in advanced photonics, nonlinear optics, and optoelectronic device engineering. The team's mission is to translate cutting-edge theoretical concepts into practical photonic technologies, emphasizing the strong coupling regime in exciton-polaritons, perovskite semiconductors, and related optical structures. With significant expertise in theoretical modeling, experimental photonics, and nanofabrication, the group's research spans fundamental studies of nanophotonic phenomena to practical implementations in lasers, sensors, and quantum photonic components.
Professor Miroshnichenko is internationally recognized for his contributions to nonlinear nanophotonics and optical nanoantennas, while Dr. Hattori brings extensive experience in optoelectronics, photodiodes, and plasmonic devices. The collaborative environment fosters multidisciplinary projects that have led to highly cited publications and significant advancements in the fields of hybrid dielectric-metal nanoresonators and metasurface technologies. These collective efforts are strategically focused on integrating novel materials and innovative photonic structures into commercially viable devices, ensuring impactful outcomes that bridge the gap between theoretical advancements and real-world applications.
Read the full article here : https://www.oejournal.org/oes/article/doi/10.29026/oes.2025.250001
Journal
Electronics
Article Title
Recent advances in exciton-polariton in perovskite
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