Photonics Spectra: GreenLight This is the syndication feed for Photonics Spectra: GreenLight. https://www.photonics.com/Splash.aspx?Tag=GreenLight Thu, 28 Mar 2024 13:57:54 GMT Mon, 30 Nov 2015 15:12:36 GMT 1800 Recycling: From Leftovers to LED Lights
Light-emitting diodes (LEDs), such as those found ubiquitously in holiday lights, television sets and other devices, now have been fabricated from food and soft-drink waste. Researchers at the University of Utah in Salt Lake City have found a method to turn food waste such as discarded pieces of tortilla into carbon dots (CDs), a type of quantum dot (QD), which are then turned into a material for use in LEDs. Their synthesis process could be an environmentally sustainable alternative to current methods of LED production.

A small LED fabricated by carbon dots. Photo courtesy of Prashant Sarswat.
Not only could the recycling method take advantage of the abundant, largely unused resource of food and beverage waste, it could also...]]>
https://www.photonics.com/Articles/Recycling_From_Leftovers_to_LED_Lights/p5/a58009 A58009 Mon, 30 Nov 2015 15:12:36 GMT
A Cooling Layer for Solar Cells
Taking advantage of the limitless cold of the universe, a transparent overlay could enable solar cells to convert more photons into electricity. As solar cells heat up in the sunlight, they become less efficient. The overlay helps cool solar cells by sending the heat into space as IR radiation. At the same time, the material is transparent to the visible light that powers the cells.

“Solar arrays must face the sun to function, even though that heat is detrimental to efficiency,” said Dr. Shanhui Fan, an electrical engineering professor. He developed the technology along with research associate Dr. Aaswath P. Raman and doctoral candidate Linxiao Zhu at Stanford University in California.

“Our thermal overlay...]]>
https://www.photonics.com/Articles/A_Cooling_Layer_for_Solar_Cells/p5/a57879 A57879 Wed, 28 Oct 2015 15:05:37 GMT
NASA Technology Aims to Save the Forests
Ravenous insects that are smaller than a penny continue to migrate north from the southeast U.S., threatening to destroy millions of pine and ash trees in the northeastern part of the country. NASA scientists have teamed with the U.S.

Forest Service to combat the problem, hoping to save millions of acres of woodlands throughout North America.

Scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md., are using the G-LiHT (Goddard LiDAR Hyperspectral and Thermal imager) airborne instrument — first developed in 2011 — to assist the U.S. Department of Agriculture’s U.S. Forest Service in understanding and combating two types of insects in particular.

The southern pine beetle, a lethal...]]>
https://www.photonics.com/Articles/NASA_Technology_Aims_to_Save_the_Forests/p5/a57788 A57788 Tue, 06 Oct 2015 14:39:23 GMT
VIS Light, Photocatalyst Deconstruct BPA
A hybrid photocatalyst that can break down bisphenol A (BPA) using visible light could eventually be used to help safely dispose of the widely used chemical. Because BPA doesn’t degrade easily, it can potentially cause harm to humans and the environment, including when it seeps into waterways.

Researchers affiliated with the University of Malaya, in Kuala Lumpur, Malaysia, and Leibniz University of Hannover in Germany, have developed a photocatalytic nanomaterial that could someday be used to treat water supplies. Their work is published in APL Materials (doi: 10.1063/1.4926454 [open access]).

BPA has been a key ingredient in the manufacture of polycarbonate plastic since the late 1950s. The ubiquitous plastic has been a...]]>
https://www.photonics.com/Articles/VIS_Light_Photocatalyst_Deconstruct_BPA/p5/a57688 A57688 Tue, 01 Sep 2015 15:00:34 GMT
Cool Roof Material Eases Energy Demands
The sun over Australia is notoriously brutal, with consistently high UV index levels. This demands air conditioners and fans, heightening most buildings’ power needs at a time when saving energy is a top priority for many. A new roofing material in development could help cool that demand and reduce energy consumption; and what better place to test it out than under the fierce Aussie sun?

The new material, developed by a team at the University of Technology, Sydney (UTS), with funding from an Australian Research Council Discovery Project grant, comprises a coated polymer stack on a silver thin film. It was tested on the roof of UTS’s Faculty of Science building, which offers a clear view of the sky with no shadowing. The...]]>
https://www.photonics.com/Articles/Cool_Roof_Material_Eases_Energy_Demands/p5/a57616 A57616 Wed, 29 Jul 2015 13:53:17 GMT
Century-Old Landmark Gets an Energy Boost
It has been more than 125 years since the grander-than-life Eiffel Tower was first designed and constructed in Paris. It officially entered the 21st century in recent months, thanks to a project meant to push a significant reduction in its ecological footprint.

In partnership with Société d’Exploitation de la Tour Eiffel (SETE, the company that operates the Eiffel Tower), New York City-based UGE International Ltd. has equipped the beloved landmark with LED lighting, solar panels and wind turbines. The work is part of a renovation and upgrade project within the City of Paris Climate Plan, led by Mayor Anne Hidalgo.

“[The mayor’s office] really wanted to make a strong statement about renewable...]]>
https://www.photonics.com/Articles/Century-Old_Landmark_Gets_an_Energy_Boost/p5/a57541 A57541 Fri, 26 Jun 2015 14:43:53 GMT
Solar Array Turns CO2 into Useful Chemicals
Efforts abound in the interest of shrinking our carbon footprint and making Earth a healthier place. Recycling paper, plastic and other materials helps, but what if we could take it a step farther and repurpose carbon dioxide emissions? Scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the University of California, Berkeley, have discovered how to do it.

With funding from the DOE Office of Science, the team of researchers has developed an artificial photosynthesis process that, with help from sunlight, could ultimately capture CO2 emissions and convert them into plastics, drugs and fuels.

“In natural photosynthesis, leaves harvest solar energy, and carbon dioxide is reduced...]]>
https://www.photonics.com/Articles/Solar_Array_Turns_COsub2_sub_into_Useful/p5/a57452 A57452 Thu, 28 May 2015 13:06:59 GMT
Oceans, Atmosphere the Focus of New NASA Mission
A satellite mission scheduled for launch in 2022 is expected to give NASA a whole new understanding of Earth’s ocea ns and atmosphere, further advancing the study of the impact environmental changes are having on ocean health and the planet’s carbon cycle.

The Pre-Aerosol Clouds and ocean Ecosystem (PACE) mission – based at the Goddard Space Flight Center in Maryland – will study the planet’s aquatic ecology and chemistry, according to scientists involved with the project. It will also allow them to “address the uncertainty in our understanding of how clouds and small airborne particles called aerosols affect Earth’s climate.”


The PACE mission will produce images such as this...]]>
https://www.photonics.com/Articles/Oceans_Atmosphere_the_Focus_of_New_NASA_Mission/p5/a57380 A57380 Mon, 27 Apr 2015 09:16:36 GMT
Light-Based Technology Aids Insect Control
Insects wreak havoc on communities with their spread of viruses and airborne diseases. They damage and even kill crops. And let’s face it: They’re just plain annoying.

There has been some relief in a “photonic fence” device, created several years ago by Intellectual Ventures Management LLC, of Bellevue, Wash., as a way of addressing the spread of malaria (courtesy of mosquitoes, in particular) in developing countries. Combining sensors and laser technology, the device can identify, track and ultimately eliminate insects. It potentially could be used by global health organizations in both developing and developed countries to combat vector-borne diseases, and in applications for agricultural use.

And now,...]]>
https://www.photonics.com/Articles/Light-Based_Technology_Aids_Insect_Control/p5/a57302 A57302 Thu, 02 Apr 2015 00:00:00 GMT
Laser Pulse Combo Sniffs Out Trace Toxic Gases
A combination of IR laser pulses and terahertz radiation (T-ray) is giving scientists a nose-up on toxic gases.

This technology can sniff out even trace amounts of harmful gases in the air – such as from a chemical spill or nerve gas attack – from up to 1 km away.

Researchers at both Duke University and the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) have had a hand in developing the sensing technology, which can differentiate between various types of gases and chemicals under normal atmospheric pressure. The technique could make it possible to test for and remove radioactive byproducts from nuclearaccidents, to detect and eradicate air pollution, and to remotely sense...]]>
https://www.photonics.com/Articles/Laser_Pulse_Combo_Sniffs_Out_Trace_Toxic_Gases/p5/a57181 A57181 Fri, 13 Feb 2015 00:00:00 GMT
Lens Arrays Could Enable Rooftop Solar Concentrators
Tiny solar cells sandwiched between lens arrays could bring the promise of concentrator photovoltaics (CPVs) down to a consumer scale.

“Current CPV systems are the size of billboards and have to be pointed very accurately to track the sun throughout the day,” said Penn State professor Dr. Noel C. Giebink. “But, you can’t put a system like this on your roof, which is where the majority of solar panels throughout the world are installed.”



Giebink led an international team that developed a prototype rooftop CPV incorporating high-efficiency GaAs cells less than a millimeter in size that need to move no more than a centimeter to keep up with the sun.

The cells were embedded between a pair...]]>
https://www.photonics.com/Articles/Lens_Arrays_Could_Enable_Rooftop_Solar/p5/a57174 A57174 Fri, 06 Feb 2015 00:00:00 GMT
Sunlight, Nanoparticles Break Down Pollutants
Endocrine disruptors mimic or block hormones, interfering with humans’ and animals’ reproductive organs, and causing other health problems.

A class of pollutants that negatively affects hormones can be broken down using nanoparticles and sunlight.

The method, developed at the Center for Advanced Materials at the Indian Association for the Cultivation of Science in Kolkata, India, neutralizes bisphenol A (BPA) and other endocrine disruptors. Endocrine disruptors can mimic or block hormones, interfering with the reproductive organs of humans and animals, and causing other health problems.


This chart demonstrates photocatalytic degradation of phenol using an rGO-Ag composite, rGO alone and Ag alone. The control...]]>
https://www.photonics.com/Articles/Sunlight_Nanoparticles_Break_Down_Pollutants/p5/a57100 A57100 Fri, 16 Jan 2015 00:00:00 GMT
SRS Probes Inner Workings of Solar Panels
Using femtosecond stimulated Raman spectroscopy (SRS), scientists have now probed the inner workings of plastic solar panels.

The findings could further efforts to improve solar panels and broaden their use, according to a team at the University of Montreal, in conjunction with England’s Science and Technology Facilities Council, Imperial College London and the University of Cyprus.

“Our findings are of key importance for a fundamental mechanistic understanding, with molecular detail, of all solar conversion systems,” said Françoise Provencher, a doctoral candidate at the University of Montreal.

Specifically, the researchers have discovered how light excites the molecules and generates current in...]]>
https://www.photonics.com/Articles/SRS_Probes_Inner_Workings_of_Solar_Panels/p5/a56747 A56747 Mon, 06 Oct 2014 00:00:00 GMT
Laser System to Measure Air Pollution from Space Station
A laser system aboard the International Space Station will help scientists track pollution in the atmosphere.

The Cloud-Aerosol Transport System (CATS), to be launched later this year, will measure atmospheric particles using photodetectors and near-infrared (1064 nm), visible (532 nm) and UV (355 nm) lasers firing at 5000 pulses per second.

The device is intended to operate for at least six months and up to three years aboard the Japanese Experiment Module-Exposed Facility, augmenting measurements gathered by NASA’s CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission, which emits 20 pulses per second at the NIR and visible frequencies.

Roughly the size of a refrigerator, CATS will...]]>
https://www.photonics.com/Articles/Laser_System_to_Measure_Air_Pollution_from_Space/p5/a56656 A56656 Tue, 09 Sep 2014 00:00:00 GMT
Tofu Chemical Could Prompt New Wave of Solar Cells
Solar cells could learn a thing or two from tofu and bath salts.

Researchers from the Stephenson Institute for Renewable Energy at the University of Liverpool in England have found that magnesium chloride (MgCl2) – found in tofu, bath salts and de-icing solutions – may produce more cost-effective and efficient solar cells. The compound could serve as a replacement for cadmium chloride (CdCl2), a toxic ingredient frequently used in solar cell technology, the researchers said.

CdCl2 is expensive to produce and requires extensive safety measures during solar cell manufacturing, the researchers said. In contrast, MgCl2 – which is extracted from sea water – is much safer, demonstrates energy efficiency...]]>
https://www.photonics.com/Articles/Tofu_Chemical_Could_Prompt_New_Wave_of_Solar_Cells/p5/a56632 A56632 Thu, 04 Sep 2014 00:00:00 GMT
Fluorescence Lifetime Measurement Enhances Recycling
Sorting plastics using fluorescence lifetime measurement could simplify and speed up the recycling process.

Developed by a team from Ludwig Maximilian University of Munich, the technique takes advantage of the intrinsic fluorescence properties found in different polymers under photoexcitation.

“Plastics emit fluorescent light when exposed to a brief flash of light, and the emission decays with time in a distinctive pattern,” said LMU professor Dr. Heinz Langhals. “Thus, their fluorescence lifetimes are highly characteristic for the different types of polymers, and can serve as an identifying fingerprint.”

The use of fluorescence lifetime measurement permits the identification and sorting of up to...]]>
https://www.photonics.com/Articles/Fluorescence_Lifetime_Measurement_Enhances/p5/a56595 A56595 Fri, 22 Aug 2014 00:00:00 GMT
Tin Replaces Lead in Promising Solar Cell
A new solar cell promises enhanced efficiency and a smaller environmental footprint.

The new cell, developed by a team from Northwestern University, uses a perovskite structure composed of tin instead of the traditional lead as the light-absorbing material. It is a low-cost, easily manufactured, environmentally friendly solar cell.

Cross-sectional view of a completed photovoltaic device using tin perovskite. Courtesy of Nature Photonics.

The tin solar cell has an efficiency of around 6 percent, which the researchers said is a solid starting point. The tin material is unique in its ability to absorb most of the visible light spectrum and in that it can dissolve and reform without heat once the solvent is removed, the...]]>
https://www.photonics.com/Articles/Tin_Replaces_Lead_in_Promising_Solar_Cell/p5/a56174 A56174 Mon, 12 May 2014 00:00:00 GMT
UV Takes Water Treatment Chemical-Free
A new UV process quickly breaks down pollutants in wastewater without help from chemical catalysts.

The system uses 172-nm light to trigger photolysis, splitting H2O molecules into highly reactive hydroxyl radicals.

“These hydroxyl compounds have an even higher reaction potential than atomic oxygen, for example,” said Siegfried Egner, head of the Physical Process Technology department at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB. “They are therefore able to decompose even very stable hydrocarbon compounds contained in harmful residues.”

A 172-nm UV radiation element. Courtesy of Fraunhofer IGB.

A challenge in developing the treatment system was that reaction...]]>
https://www.photonics.com/Articles/UV_Takes_Water_Treatment_Chemical-Free/p5/a56132 A56132 Fri, 02 May 2014 00:00:00 GMT
Solar Cell by Day, Light Panel by Night
A chance discovery has brought light emission properties to solar cells.

A new solar cell material developed by a team at Nanyang Technological University (NTU) not only converts light to electricity, but also emits light.

The hybrid perovskite solar cell material was discovered to glow brightly and emit light when a laser is shined on it.

Perovskite solar cells have been discovered to have light-emitting properties. Courtesy of Nanyang Technological University.
"What we have discovered is that because it is a high-quality material and very durable under light exposure, it can capture light particles and convert them to electricity, or vice versa," said Sum Tze Chien, an assistant professor with NTU's School of Physical...]]>
https://www.photonics.com/Articles/Solar_Cell_by_Day_Light_Panel_by_Night/p5/a55997 A55997 Tue, 25 Mar 2014 00:00:00 GMT
Tapping solar’s full potential
Solar cells may be a little closer to full realization of their potential, thanks to the creation of large sheets of nanotextured silicon microcell arrays. The discovery promises to make solar cells lightweight, bendable, more efficient and easily mass-produced.

Converting sunshine into electricity is not a difficult process, although the lack of a national solar cell network reveals that much of the difficulty lies in doing so efficiently and on a large scale.

A printed solar cell is shown. Researchers have created large sheets of nanotextured silicon microcell arrays that could make solar cells easier to mass-produce. Photo courtesy of University of Central Florida.
But a team from the University of Illinois at...]]>
https://www.photonics.com/Articles/Tapping_solarrsquos_full_potential/p5/a55933 A55933 Fri, 07 Mar 2014 00:00:00 GMT