The ability to convert the sun’s energy into electricity has changed the energy industry globally. Last year, more than 90 gigawatts of solar capacity were installed worldwide, equivalent to the total electricity production of the whole of Turkey.
However, researchers believe that in the coming years, solar energy can become more efficient and cheap than it is now. While most modern photovoltaic cells are made of silicon, a key area of enhancing the ability of industry to use new materials for their production.
One of the most promising of them is the family of crystals known as perovskites (named after the Russian geologist Perovsky Lion). Some perovskites very well absorb light, with their help, the scientists have managed to obtain 22 percent energy conversion efficiency, which roughly corresponds to the traditional silicon elements.
To date, the characteristics and efficiency of the perovskites was superior to other alternative solar materials such as dye-sensitized solar cells (Graetzel cells) or organic solar cells. More and more scientists make optimistic forecasts about the progress of solar energy technologies on the basis of perovskites, although for the first time since this purpose they began to use not more than 10 years ago.
However, there are still some significant obstacles for a mass implementation of perovskites in commercial products. Because the crystals dissolve easily in water, they must be protected from moisture with a hermetic glass plates. Furthermore, although scientists and achieved high efficiency with very small perovskite cells, they failed to get the same effect with larger cells.
“Perovskites are certainly not as stable as silicon, says Michael McGee, a Professor of materials science at Stanford University. – What is the main problem. Another thing is that the perovskites is a completely new technology that has not yet been scaled and manufacturing factories not yet built. It will take some time.”
No company produces commercial perovskite solar cells on a large scale, although one of them – Oxford PV (a division of the University of Oxford) – has a pilot plant for the production of solar cells in Germany.
Research centers and small companies, studying the perovskites, are now entering the struggle for a higher level of funding comparable with infusions of cash in silicon technology.
“Today it is difficult to resist on silicon is equal to or defeat it, – explains McGee. The reason is that this technology already has huge economies of scale”.
In the short term, one of the solutions proposed by Professor McGee, is the use of “tandem” solar cells, in which the perovskite layer is applied on top of traditional silicon. Semitransparent perovskite cell captures certain wavelengths in the visible light spectrum, allowing you to ignore others who then disposed of the silicon element under it.
Research team McGee showed that the tandem solar cells is 10% more efficient than silicon counterparts. This could be the opening that will allow you to get new material on the market, which is dominated by silicon.
Overcoming the problems of small scale and stability, perovskite solar cells can turn the entire solar industry because they are much cheaper to produce than silicon solar cells. The crystals of perovskite can be obtained at relatively low temperatures, unlike silicon, which requires a huge amount of heat for the manufacture of wafers.
“We hope to come to one penny per watt [1 ≈ 1 cent]. This is the purpose of creating these solar panels, says Nitin Padura, Director of the Institute for molecular and nanoscale innovation at brown University. – Versatility and capacity of these materials is very exciting”.