A group of scientists from MIT have just created the thinnest solar cells in the world, which are about as light as a soap bubble. These cells can be used on any type of surface or material, such as clothes or even smartphones.
This groundbreaking discovery was published in the journal Organic Electronics and, according to researchers, it may be applied for a new generation of mobile electronic devices.
Professor Vladimir Bulovic from MIT was a part of this research and he explains that the most important aspect of this procedure was creating the solar cell, the supporting substrate and the overcoating that protects it from the outside environment in one single process.
One of the main characteristics of the substrate is that it does not need to be removed for cleaning or other purposes during fabrication, therefore limiting the exposure to dust or other fragments that could potentially contaminate the cell and lower its overall performance.
For the purpose of this research, the scientists used a flexible material called parylene (which functions both as the substrate and as the overcoating) and an organic component known as DBP (which works as the main light-absorbing layer).
Parylene is basically a plastic layer which is used in printed circuit boards and implanted biomedical devices in order to protect them from environmental damage.
These solar cells are created in a vacuum chamber, at room temperature. Since this process requires extremely high temperatures and the use of hard chemicals, solvents are strictly excluded.
Furthermore, in order to “grow” the substrate and the solar cells, scientists adopt a vapour deposition technique. Apparently, the solar cell that results from this procedure are so thin and light that it can even be placed on top of a soap bubble and it would not even risk popping it.
According to researchers, this solar cell is much too thin for practical use, but there is the possibility of depositing parylene films that are 80 microns thick through a commercial equipment, which allows the in-line sublayer to keep all its benefits.
This flexible parylene film is first placed on a reliable material, which in this research is glass. After the process is finished, the scientists have to carry the total solar cell formation through a film-based structure.
The resulting solar cells, along with the substrate and the overcoating, amount to just one-fiftieth of a human hair’s thickness. This means they are around two micrometres thick, which is pretty astonishing, considering the fact that they can use sunlight to form electricity just as effectively as their glass-based correspondents.
Image Source: MIT.edu