The expansion of solar photovoltaic systems in Germany continues to grow as more companies and private households opt for solar energy.
Category: solar power – Page 11
Scientists are closer to giving the next generation of solar cells a powerful boost by integrating a process that could make the technology more efficient by breaking particles of light—photons—into small chunks.
In a study published in Nature Chemistry researchers unravel the scientific understanding of what happens when light particles split—a process called singlet fission —and its underlying workings.
Lead researcher Professor Tim Schmidt from UNSW Sydney’s School of Chemistry has studied singlet fission for more than a decade. He says the process could be invoked and applied to improve existing silicon solar cell technologies.
This remarkable miniature rotorcraft is so lightweight and efficient that it can lift its own mass given nothing but sunlight. The entire thing weighs about as much as four paperclips, and it can fly all day if the sun’s shining.
Researchers at China’s Beihang University and the Center of Advanced Aero-Engine, have unveiled CouloumbFly, a palm-sized miniature rotorcraft that weighs just 4.21 g (0.15 oz) – yet still boasts a rotor diameter of 20 cm (7.9 in), making it around 600 times lighter than any other comparable small solar-powered drone.
In tethered testing under natural sunlight conditions, CouloumbFly got itself airborne within a second and managed an hour of flight without power diminishing, before a mechanical failure brought it back down. Not much of a big deal if it was a glide-capable winged drone – but this is a miniature helicopter that’s entirely responsible for generating its own lift, and managing that on solar energy alone is an extraordinary feat.
Two 650-foot-tall (200-m) towers have risen in China’s Gansu Province. Combined with an array of 30,000 mirrors arranged in concentric circles, the new facility is expected to generate over 1.8 billion kilowatt-hours of electricity every year.
While photovoltaic panels that directly convert sunlight to electricity are what most people think of when they hear the term “solar power,” there is another method of harvesting the Sun’s power that’s been steadily developing since the early 1980s. Known as solar thermal or concentrated solar power (CSP), these systems rely on mirrors known as heliostats to bounce sunlight to a central gathering point. There, the concentrated beams heat a transfer fluid that in turn heats a working fluid. This fluid then evaporates, turns a turbine, and generates electricity.
In 2014, what was then the world’s largest solar thermal power station opened in the Mojave Desert in the United States. Known as the Ivanpah Solar Electric Generating System, the facility consists of three different towers surrounded by heliostat arrays and has a capacity of 392 megawatts. In 2017, Australia announced that it was building the world’s largest single-tower solar thermal power plant with a proposed output of 150 megawatts, although that project was ultimately killed in 2019. The world’s largest CSP, the Noor Complex Solar Power Plant, now operates in the Sahara Desert in Morocco where it churns out 510 megawatts of power.
In the search for more efficient and sustainable energy generation methods, a class of materials called metal halide perovskites have shown great promise. In the few years since their discovery, novel solar cells based on these materials have already achieved efficiencies comparable to commercial silicon solar cells.
Scientists at the City University of Hong Kong (CityUHK) have developed highly efficient, printable and stable perovskite solar cells to achieve carbon neutrality and promote sustainable development.
The new type of perovskite solar cells can be mass-produced at a speed comparable to newspaper printing, with a daily output of up to 1,000 solar panels. Owing to their flexible, semi-transparent characteristics, they can also be made into light-absorbing glass windows, realizing the concept of “urban solar farms” in cities with many high-rise buildings.
The research is led by the Lee Shau Kee Chair Professor of Materials Science at CityUHK, Professor Alex Jen Kwan-yue, and the results were published in Nature Energy.
In the past decade, metal-halide perovskites have rapidly progressed as a semiconductor, surpassing silicon in their ability to convert light into electric current since their initial discovery.
Simulations on TACC’s Frontera and Lonestar6 supercomputers have revealed surprising vortex structures in quasiparticles of electrons and atoms, called polarons, which contribute to generating electricity from sunlight.
This new discovery can help scientists develop new solar cells and LED lighting. This type of lighting is hailed as an eco-friendly, sustainable technology that can reshape the future of illumination.
A research effort led by scientists at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) has made advances that could enable a broader range of currently unimagined optoelectronic devices.
The researchers, whose previous innovation included incorporating a perovskite layer that allowed the creation of a new type of polarized light-emitting diode (LED) that emits spin-controlled photons at room temperature without the use of magnetic fields or ferromagnetic contacts, now have gone a step further by integrating a III-V semiconductor optoelectronic structure with a chiral halide perovskite semiconductor.
That is, they transformed an existing commercialized LED into one that also controls the spin of electrons. The results provide a pathway toward transforming modern optoelectronics, a field that relies on the control of light and encompasses LEDs, solar cells, and telecommunications lasers, among other devices.
Luminescence refers to the result of a process in which an object absorbs light at one wavelength and then re-emits it at another wavelength. Through light absorption, electrons in the ground state of the material are excited to a higher energy state. After a certain amount of time characteristic of each excited state, the electrons decay to lower energy states, including the ground state, and emit light. The phenomenon is used in a wide array of technological applications involving highly efficient and reproducible emitting devices that can easily be miniaturized.
The materials with the highest luminescence efficiency include quantum dots (QDs), currently used in high-resolution displays, LEDs, solar panels, and sensors of various kinds, such as those used for precision medical imaging. Functionalization of the surface of QDs with various types of molecules permits interaction with cellular structures or other molecules of interest for the purpose of investigating molecular-level biological processes.
QDs are semiconductor nanoparticles whose emissive characteristics are directly linked to dot size, owing to the phenomenon of quantum confinement. For this reason, monitoring and control of crystal growth during synthesis of QDs in solution permits intelligent planning of the desired luminescence.
A theoretical model for the illumination of photosynthesizing algae in giant clams suggests principles for high efficiency collection of sunlight.
Crops on a farm capture only about 3% of the available solar energy, much less than the 20%–25% captured by large solar arrays. Now a research team has used a theoretical model to explain efficiencies as high as 67% for photosynthesizing algae hosted by giant clams [1]. The researchers argue that clams achieve this performance with an optimized geometry. The mollusks may also adjust the algae clusters’ spacing according to changing light conditions. The researchers hope that an understanding of clams’ solar efficiency might help other scientists improve the efficiency of solar technology and explain aspects of the photosynthetic behavior of other ecosystems such as forests.
A photosynthetic cell can convert nearly every incoming photon to usable energy, says biophysicist Alison Sweeney of Yale University. But efficiency is much lower in larger systems such as agricultural fields. “Can we achieve near-perfect efficiencies over large land areas? This is an urgent question” as researchers try to reduce reliance on fossil fuels, Sweeney says.