Solar cells based on perovskites reach high efficiencies: They convert more than 20 percent of the incident light directly into usable power. On their search for underlying physical mechanisms, researchers of the Karlsruhe Institute of Technology (KIT) have now detected strips of nanostructures with alternating directions of polarization in the perovskite layers. These structures might serve as transport paths for charge carriers. This is reported in the Energy & Environmental Science Journal.
The perovskites used by the KIT scientists are metal organic compounds with a special crystal structure and excellent photovoltaic properties. Since their discovery in 2009, perovskite solar cells have experienced a rapid development. Meanwhile, they reach power conversion efficiencies of more than 20 percent. This makes them one of the most promising photovoltaic technologies. Research into perovskite solar cells, however, faces two special challenges: The light-absorbing layers have to be made more robust to environmental impacts and the lead contained therein has to be replaced by environmentally more compatible elements. This requires in-depth understanding of physical mechanisms that enable the high conversion rate of absorbed solar energy into electric power.
By replacing the phosphor screen in a laser phosphor display (LPD) with a luminescent solar concentrator (LSC), one can harvest energy from ambient light as well as display high-resolution images. "Energy-harvesting laser phosphor display and its design considerations," published recently by SPIE, the international society for optics and photonics, in the Journal of Photonics for Energy, describes the development, processes, and applications of an LPD.
In a proof-of-concept experiment, lead author Ichiro Fujieda and his collegeagues at Ritsumeikan University fabricated a 95 × 95 × 10 mm screen by sandwiching a thin layer of coumarin 6 with two transparent plates. These plates guided the photoluminescent (PL) photons emitted in both directions toward their edge surfaces. After removing the light source in a DMD-based commercial grade projector and feeding a blue laser beam into its optics, the screen generated green images.
While recent media reports have condemned a commonly used agricultural pesticide as detrimental to honey bee health, scientists with the University of Tennessee Institute of Agriculture have found that the overall health of honey bee hives actually improves in the presence of agricultural production.The study, “Agricultural Landscape and Pesticide Effects on Honey Bee Biological Traits,” which was published in a recent issue of the Journal of Economic Entomology, evaluated the impacts of row-crop agriculture, including the traditional use of pesticides, on honey bee health. Results indicated that hive health was positively correlated to the presence of agriculture. According to the study, colonies in a non-agricultural area struggled to find adequate food resources and produced fewer offspring.
In May, a team of Goddard scientists will begin measuring greenhouse gases over the Mid-Atlantic region — an area chosen in part because it encompasses a range of vegetation, climate, and soil types that would influence the exchange of carbon dioxide and methane between the Earth and the atmosphere.
The airborne campaign, called the Carbon Airborne Flux Experiment, or CARAFE, could help scientists better understand the exchange process, also known as flux, and improve computer models that predict Earth’s carbon sinks, natural or artificial areas that absorb carbon dioxide or methane.
Glacier flow at the southern Antarctic Peninsula has increased since the 1990s, but a new study has found the change to be only a third of what was recently reported.
Ducks in North America can be carriers of avian influenza viruses similar to those found in a 2016 outbreak in Indiana that led to the losses of hundreds of thousands of chickens and turkeys, according to a recent study.
Kick-starting action on the recently-adopted Global Forest Goals to protect, sustainably manage and increase world’s forest area will be a key focus for delegations gathered in New York for the twelfth session of the UN Forum on Forests, which opened today at United Nations Headquarters.
It is a common trope in disaster movies: an earthquake strikes, causing the ground to rip open and swallow people and cars whole. The gaping earth might make for cinematic drama, but earthquake scientists have long held that it does not happen.
Two immune responses are important for recovery after a heart attack — an acute inflammatory response that attracts leukocyte immune cells to remove dead tissue, followed by a resolving response that allows healing.
A UBC-led research team has developed a new global coral bleaching database that could help scientists predict future bleaching events.
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