Tuesday, February 3, 2015

Growing Cheap & Efficient Solar Cells

Solar Technology

Perovskite Structure with a chemical formula ABX3. Wikipedia says; “The red spheres are X atoms (usually oxygens), the blue spheres are B-atoms (a smaller metal cation, such as Ti4+), and the green spheres are the A-atoms (a larger metal cation, such as Ca2+). Pictured is the undistorted cubic structure; the symmetry is lowered to orthorhombic, tetragonal or trigonal in many perovskites.”
Source: Wikipedia; original uploader: Cadmium

An article in Compound Semiconductor journal writes about perovskites, which are able to convert parts of the solar spectrum into electricity more efficiently than silicon, thus reducing the cost of solar power. The article ("Los Alamos Develops New Technique For Growing Perovskite Solar Cells"; 30th January 2015) says:
This week in the journal Science, Los Alamos National Laboratory researchers revealed a new solution-based hot-casting technique that allows growth of highly efficient and reproducible solar cells from large-area perovskite crystals.

"These perovskite crystals offer promising routes for developing low-cost, solar-based, clean global energy solutions for the future," said Aditya Mohite, the Los Alamos scientist leading the project.

State-of-the-art photovoltaics using high-purity, large-area, wafer-scale single-crystalline semiconductors grown by sophisticated, high temperature crystal-growth processes are seen as the future of efficient solar technology. Solar cells composed of organic-inorganic perovskites offer efficiencies approaching that of silicon, but they have been plagued with some important deficiencies limiting their commercial viability. It is this failure that the Los Alamos technique successfully corrects.
As a note of interest, Wikipedia says, “Perovskites take their name from the mineral, which was first discovered in the Ural mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist L.A. Perovski (1792–1856).” Perovskites have the same structure as calcium titanium oxide, or CaTiO3. 

As a class of crystals, they have drawn the attention of energy scientists interested in the field of photovoltaics, “because of their low cost, high charge-carrier mobility, and long diffusion lengths,” says the engineering journal, IEEE Spectrum in a recent article on the subject. “In real world terms, this means that the electrons in perovskite-based photovoltaics can travel through thicker solar cells, which absorb more light and thereby generate more electricity than thinner cells.”

For a newer technology to displace an older established one it has to prove both cost-effective and efficient; now, solar technology is very close to achieving this and is in a good position to displace (and replace) fossil fuels. This is something to cheer about.

For more, go to [CompoundSemiconductor]