Coating magic elevates solar panel power to a 31% efficiency milestone
Researchers have developed a strategy for surface passivation that allows the surface defects of the perovskite layer to be smoothed out. A new coating of special organic molecules can pave the way for a new generation of solar panels, according to the researchers.
This coating can increase the efficiency of monolithic tandem cells made of silicon and perovskite while also lowering their cost as they are made of standard silicon wafers. The team of researchers has developed a strategy for surface passivation that allows the perovskite layer’s surface defects to be smoothed out.
Light knocks electrons out of a semiconductor, leaving behind positively charged “holes” in solar cells. These two charge carriers are separated and can be carried as current. Tandem cells were then developed to better exploit the entire spectrum of sunlight and increase the efficiency of solar cells.
Monolithic tandem cells are made by coating a support with two types of semiconductors, one on top of the other. For a perovskite/silicon system, this is usually achieved by using silicon wafers that are produced by the zone melting process and have a polished or nanostructured surface.
A thiophenethylammonium compound with a trifluoromethyl group (CF3-TEA) is applied by a dynamic spray coating process. This forms a very uniform coat—even on microtextured surfaces. Owing to its high polarity and binding energy, the CF3-TEA coating can effectively decrease the surface defects’ effect.
Nonradiative recombination is suppressed, and the electronic levels are adjusted so that the electrons at the interface can be more easily transferred to the electron-capturing layer of the solar cell. Surface modification with CF3-TEA allows perovskite/silicon tandem solar cells based on common textured wafers made of Czochralski silicon to attain a very high efficiency of nearly 31% and maintain long-term stability.
Source: https://interestingengineering.com/energy/solar-cell-coating-boosts-efficiency