I like the way science evolves and still, for years, nobody seems to look at the new inventions. This may be the case with solar, because almost weekly we discover news about useful inventions in the area of solar power. Instead, old and inefficient methods are still being commercialized and “promoted”, at their high prices, like it’s wanted to decrease their real usage in real life conditions, not promote it.
A few days ago, researchers from the Rensselaer Polytechnic Institute made public a new way of improving current solar panels by using nanotechnology to create an anti-reflective coating for them.
“To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “Our new antireflective coating makes this possible.”
Current techniques that maximize the exposing of the solar cell to the Sun’s maximum light capturing angle is made by using complicated electronics and computing system, that either follow the Sun by successive approximations, or that calculate the Sun’s position according to a special software.
Shawn-Yu’s anti-reflexive coating does just that and more: it makes the cell absorb 92.21 percent of the incoming light, compared to the 67.4 percent that the solar cell would catch if it hadn’t any coating on it.
“At the beginning of the project, we asked ‘would it be possible to create a single antireflective structure that can work from all angles?’ Then we attacked the problem from a fundamental perspective, tested and fine-tuned our theory, and created a working device,” Lin said. Rensselaer physics graduate student Mei-Ling Kuo played a key role in the investigations.
Classic anti-reflexive coatings are engineered to transmit light of one particular wavelength through them. Lin’s new coating stacks seven of these layers, one on top of the other, in such a way that each layer enhances the antireflective properties of the layer below it. These additional layers also help to “bend” the flow of sunlight to an angle that augments the coating’s antireflective properties. This means that each layer not only transmits sunlight, it also helps to capture any light that may have otherwise been reflected off of the layers below it.
The seven layers, each with a height of 50 nanometers to 100 nanometers, are made up of silicon dioxide and titanium dioxide nanorods positioned at an oblique angle – each layer looks and functions similar to a dense forest where sunlight is “captured” between the trees. The nanorods were attached to a silicon substrate via chemical vapor disposition, and Lin said the new coating can be affixed to nearly any photovoltaic materials for use in solar cells, including III-V multi-junction and cadmium telluride.
If this invention is applied to more efficient solar cells, like the ones Nanosolar is trying to make, or William Yuan’s 3D models (when they will be brought to reality), combined with a solar concentrator, we will be able to harvest a lot of energy by just “staring at the Sun”. People are going to fly to Mars… aren’t they (we) able to make themselves simpler sources of energy? Or… do we still have enough money, blue sky above and green grass under our bare feet, not to care? Well, for how long?
