Physicists at Boston College have developed a nano-scale solar cell, inspired by the coaxial cable, which offers greater efficiency than any previously designed nanotech thin film solar cell

A limiting factor in making highly efficient thin film sollar cells is the need for the cells to be thick enough to collect a sufficient amount of light, yet thin enough to extract current. The Boston College researchers have found a way to resolve this challenge using a coaxial design for cells constructed with amorphous, rather than crystalline, silicon

The researchers say that the nanocoax cells yield power conversion efficiency in excess of 8 percent, which is higher than any nanostructured thin film solar cell to date.

"Many groups around the world are working on nanowire-type solar cells, most using crystalline semiconductors," said Michael Naughton, a professor of physics at Boston College. "This nanocoax cell architecture, on the other hand, does not require crystalline materials, and therefore offers promise for lower-cost solar power with ultrathin absorbers. With continued optimization, efficiencies beyond anything achieved in conventional planar architectures may be possible, while using smaller quantities of less costly material."

If you found this item interesting, please let others know:

A team led by Professor Benoît Marsan at the Université du Québec à Montréal say that they have solved some of the problems have been hampering the development of efficient and affordable solar cells.

One of the most promising solar cells designs is the dye-sensitized cell, which was designed in the early ’90s based on the principle of photosynthesis. A dye-sensitized solar cell consists of a porous layer of nanoparticles of a white pigment (titanium dioxide) covered with a molecular dye that absorbs sunlight. The pigment-coated titanium dioxide is immersed in an electrolyte solution with a platinum-based catalyst. Sunlight passes through the platinum-based cathode and the electrolyte, and then withdraws electrons from the titanium dioxide anode.

This type of cell has some problems that have prevented its large-scale commercialisation:

• The electrolyte is extremely corrosive, resulting in a lack of durability
• The titanium oxide is a densely coloured, preventing the efficient passage of light; and
• The cathode is covered with platinum, which is expensive, non-transparent and rare.

Professor Marsan realized that two of the technologies developed for the electrochemical solar cell could also be applied to the dye-sensitized solar cell. Entirely new molecules, created in the laboratory, can be used in a liquid or gel electrolyte which is transparent and non-corrosive -  thus improving the cell’s output and stability - and platinum can be replaced by cobalt sulphide, which is far less expensive, more efficient, more stable and more readily available.

If you found this item interesting, please let others know:

Researchers at the California Institute of Technology in Pasadena have reported in Nature Materials journal that they have devised a way to make flexible solar cells with silicon wires that use just 1 percent of the material needed to make conventional solar cells.

The new material uses conventional silicon configured into micron-sized wires instead of brittle wafers and encases them in a flexible polymer that can be rolled or bent. The eventual hope is to make thin, light solar cells that could be incorporated into materials such as clothing but the immediate benefit is cheaper and easier-to-install solar panels.

The researchers claim that the material would be about 15 to 20 percent efficient - about the same as solar cells currently used in rooftop panels.

These efficiencies are achieved because the wires absorb sunlight over a broader range of wavelengths and incidence angles than conventional solar panels, despite occupying only a fraction of the panel’s volume.

If you found this item interesting, please let others know:

One of the biggest challenges for architects and developers wanting to integrate solar power generation with building materials is aesthetics. Many building-integrated solar technologies are also somewhat inefficient, which means that large parts of a building have to be covered with solar energy-gathering materials to get significant benefits.

The Center for Architecture and Science, which is a research and development collaboration between Rensselaer Polytechnic Institute and architecture and engineering companies, including the architecture firm Skidmore, Owings & Merrill, thinks that its "Dynamic Solar Facade" can overcome these challenges.

The Dynamic Solar Facade is a glass frontage with rows of transparent, pyramid-shaped concentrators configured in a honeycomb pattern and hung on wires that move up and down, or twist side to side, to track the sun. Each concentrator has a lens that magnifies light nearly 500 times and directs it onto a solar cell made of gallium arsenide. The concentrators also bring light into the building while deflecting heat and glare, reducing the need for artificial light during the day.

The group claims that the Dynamic Solar Facade uses the sun’s light and heat with 60 to 80 percent efficiency.

The first full-scale demonstration project has just been installed  at the Syracuse Center of Excellence in Environmental and Energy Systems, which is scheduled to open in March. It comprises 64 concentrators in an 2.4-by-3-metres glass installation.

The Solar Facade is apparently stylish enough to satisfy the Fashion Institute of Technology in New York.which plans to include it in a new student centre.
 

(Image: Centre for Architecture and Science)

If you found this item interesting, please let others know:

Researchers led by Dr Zhong Wang of the Georgia Institute of Technology have developed what they call the world’s first 3-D solar panel system. They claim that their system is cheaper, and up to six times more efficient, than conventional. planar solar cells.

Instead of using traditional solar panels, the system captures sunlight and turns it into electricity within fibre optic cables.

The scientists seeded optical fibres with zinc oxide nanostructures. Those nanostructures were then coated with a dye-sensitized material that converts light into electricity. The electricity is then captured using a liquid electrolyte surrounding the nanostructures.

Only the very tip of the cable needs to be exposed to light, meaning that most of the system can easily be concealed under roofs, in walls or even underground. This not only opens up architectural opportunities for concealing the solar panels but enables them to be protected from envirommental damage, such as from hail.

When any light which is not absorbed and converted into electricity reaches the end of the cable, it bounces back - doubling the chance of absorption. Dr Wang says that the result is up to six times more efficient than standard, planar solar cells with the same surface area.

The 3-D solar cells are cheap to manufacture because their main components are common materials like the fibre optic cables used in telecommunications and zinc oxide which is commonly used as a sunscreen, and because the manufacturing process requires much lower temperatures (about 70°C) than conventional solar cell production.

If you found this item interesting, please let others know:

A team of researchers, led by Professor Martin Green, Research Director of the ARC Photovoltaics Centre of Excellence at  the University of New South Wales, have claimed the highest efficiency for solar power ever recorded.

The team has achieved 43% of sunlight converted into electricity at the research stage. The UNSW team combined a cell developed locally with cells supplied by two US groups to demonstrate a multi-cell combination that has set the new benchmark.

Professor Green said that "because sunlight is made up of many colours of different energy, ranging from the high energy ultraviolet to the low energy infrared, a combination of solar cells of different materials can convert sunlight more efficiently than any single cell".

The team used its five-cell combination to convert 43% of the sunlight hitting it into electricity, improving on the previous world record of 42.7% held by the University of Delaware.

Last year, Professor Green’s ARC Photovoltaics Centre of Excellence team set a world record of 25 per cent efficiency for an individual solar cell.

If you found this item interesting, please let others know:

Scientists from the Rensselaer Polytechnic Institute in New York have developed a new design for solar panels which dramatically increases their efficiency

The solar panels have rows of miniature concentrator lenes with concententric grooves which track the sun’s movement and focus it on postage-stamp sized solar cells. Microchannels at the base of the module transfer energy in the form of heat and light to wires contained inside the channels.

Conventional solar systems are about 14 percent efficient. This system has a combined heat and power efficiency of nearly 80 percent.

Anna Dyson, an architectural scientist from the Rensselaer Polytechnic Institute says that "we basically have a system that can sense where the sun is at any time, and then the modules will basically be facing directly perpendicular to the incoming sun rays".

The lenses will be nestled between window panes and all of the pieces will be made of glass. Rows or stacks of these can be incorporated into a building’s facade.This will also lower the lighting needs of buildings, as it will provide usable light inside the building. It could supply as much as 50 percent of the energy needed for a building to operate.

The system is being installed in the Center for Excellence and Environmental Energy Systems in Syracuse, New York and will also be installed in the Fashion Institute of Technology in New York City.

If you found this item interesting, please let others know:

The CSIRO’s Future Manufacturing Flagship is developing flexible, large area, cost-effective printable plastic solar cells.

The research is based on the polymer technology which the CSIRO developed for printing plastic banknates and which is now used in 21 countries as well as Australia.

The initial printing trials are being conducted at Securency International, a banknote printing company.

Launching the trials, Victorian Minister for Energy and Resources, Peter Batchelor, said “These solar cells are cutting edge technology and offer advantages over traditional solar technology because of the potential to mass produce the cells cheaply and install them over large areas such as rooftops. “The technology used for these cells is still in its infancy, but this project aims to speed-up the development of this technology and take it from research to rooftops as quickly as possible.”

Mr Batchelor said the project was at the half way point and the progress being made was extremely good with these printing trials occurring six months ahead of schedule.

The Minister for Innovation, Industry, Science and Research, Senator Kim Carr said "The trial could also lay the ground work for a world leading Australian industry in printable electronics."

If you found this item interesting, please let others know:

Scientists at Harvard University and IBM are hoping to harness the power of a million idle computers to develop a new, cheaper form of solar power.

Researchers have launched the project using IBM’s World Community Grid, which taps into volunteers’ computers across the globe to run calculations on a myriad of compounds — potentially shortening a project that could take 22 years to just two years.

Harvard scientists are hoping the project will allow it to discover a combination of organic materials that can be used to manufacture plastic solar cells that are cheaper and more flexible than the silicon-based ones typically used to turn sunlight into electricity.

If you’re interested in being a volunteer, all you meed to do is download a bit of software (which includes a security package), and the calculations run as a screensaver. Essentially, you’re volunteering your computer, as well as a fraction of your power - but this is one case where the power isn’t being wasted – it’s being used for a great environmental cause.

If you found this item interesting, please let others know:

The University of New South Wales’ ARC Photovoltaic Centre of Excellence has created the first silicon solar cell to achieve the milestone of 25 per cent efficiency.

The UNSW ARC Photovoltaic Centre of Excellence already held the world record of 24.7 per cent for silicon solar cell efficiency. Now the team led by Professors Martin Green and Stuart Wenham and widened their lead on the rest of the world.

Professor Green said the jump in performance leading to the milestone resulted from new knowledge about the composition of sunlight. "Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green." he said.

The new world mark in converting incident sunlight into electricity is one of six world records claimed by UNSW for its silicon solar technologies.

If you found this item interesting, please let others know: