Materials Science and Engineering researchers at Penn State (The Pennsylvania State University), United States, have developed new ultra-thin metal electrodes useful for creating transparent perovskite solar cells , which stand out for being highly efficient and for allowing their coupling with silicon cells. traditional, greatly improving performance.
This research, whose findings have been published in the journal Nano Energy , would represent a huge step forward towards the development of completely transparent solar cells , which, in the future, could be installed in the windows of homes and office buildings for the generation of electricity from sunlight that would otherwise be lost.
Traditional solar cells are made from silicon, but researchers believe they are approaching the limits of technology to create vastly more efficient solar cells. In the case of perovskite cells , for example, they provide a promising alternative, such that stacking them on top of traditional cells would allow much more efficient tandem devices to be created.
On a previous occasion, the same group of scientists demonstrated that it is possible to make electrodes from very thin atomic layers of gold, with high electrical conductivity, and without interfering with the cell’s ability to absorb sunlight.
On this occasion, the perovskite solar cell developed by the team has reached 19.8% efficiency , reaching a record for a semi-transparent solar cell. But the experts decided to do more tests and combined it with a traditional silicon solar cell. This tandem device achieved an efficiency of 28.3%, compared to 23.3% achieved by the silicon cell individually. The result? A 5% improvement in efficiency , something that, according to experts, “is huge.”
As the scientists put it, “this means you are converting about 50 more watts of sunlight for every square meter of solar cell material.” In this sense, “solar farms can consist of thousands of modules, so that adds a lot of electricity, and it is a great advance”.
The team, in fact, found that chromium, used as a layer, offered the possibility for the gold to form on top in a continuous ultra-thin layer, with good properties to conduct electricity.
In this case, the perovskite solar cells are made up of a total of five layers and other proven materials, such as degraded layers of the cells or damaged transparent electrodes.
In turn, they found that solar cells made with gold electrodes are stable, in addition to maintaining high efficiencies over time (at least, in laboratory tests).
Reference: Dong Yang et al, 28.3% -efficiency perovskite / silicon tandem solar cell by optimal transparent electrode for high efficient semitransparent top cell, Nano Energy (2021). DOI: 10.1016 / j.nanoen.2021.105934
