Next-generation solar cells get to 24% efficiency

• A German research study team has developed a tandem solar cell that gets to 24 percent efficiency-- measured according to the fraction of photons exchanged electricity (i.e., electrons).

This sets a new globe document as the greatest efficiency accomplished up until now with this combination of organic and perovskite-based absorbers. The solar cell was developed by Professor Dr. Thomas Riedl's team at the University of Wuppertal along with researchers from the Institute of Physical Chemistry at the University of Cologne as well as various other project companions from the Universities of Potsdam and Tübingen along with the Helmholtz-Zentrum Berlin and also the Max-Planck-Institut für Eisenforschng in Düsseldorf. The results have actually been published in Nature under the title "Perovskite-- organic tandem solar cells with indium oxide interconnect."

Conventional solar cell modern technologies are mostly based on the semiconductor silicon and also are currently taken into consideration to be "comparable to it gets." Significant enhancements in their efficiency-- i.e., a lot more watts of electrical power per watt of solar radiation gathered-- can rarely be expected. That makes it even more required to develop new solar technologies that can make a decisive payment to the power transition. 2 such alternative absorber materials have been integrated in this work. Below, organic semiconductors were utilized, which are carbon-based substances that can carry out electricity under particular conditions. These were coupled with a perovskite, based on a lead-halogen compound, with exceptional semiconducting homes. Both of these technologies require substantially less material and power for their production contrasted to standard silicon cells, making it possible to make solar cells even more sustainable.

As sunlight consists of various spooky components, i.e., shades, efficient solar cells need to convert as much of this sunlight as possible right into electricity. This can be attained with so-called tandem cells, in which different semiconductor materials are incorporated in the solar cell, each of which absorbs various series of the solar range. In the existing research the organic semiconductors were used for the ultraviolet and also visible parts of the light, while the perovskite can successfully absorb in the near-infrared. Similar combinations of products have currently been explored in the past, today the study team prospered in dramatically enhancing their performance.

At the beginning of the project, the world's ideal perovskite/organic tandem cells had an efficiency of around 20 percent. Under the management of the University of Wuppertal, the Cologne scientists, along with the various other project companions, had the ability to raise this value to an extraordinary 24 percent. "To attain such high efficiency, the losses at the user interfaces in between the products within the solar cells had to be lessened," stated Dr. Selina Olthof of the University of Cologne's Institute of Physical Chemistry. "To solve this problem, the team in Wuppertal developed a supposed interconnect that couples the organic sub-cell as well as the perovskite sub-cell electronically and optically."

As the interconnect, a thin layer of indium oxide was incorporated into the solar cell with a thickness of merely 1.5 nanometers to maintain losses as reduced as possible. The scientists in Cologne played an essential role in evaluating the energised as well as electrical homes of the user interfaces as well as the interconnect in order to identify loss procedures and also more maximize the components. Simulations by the team in Wuppertal showed that tandem cells with an efficiency of more than 30 percent could be attained in the future with this technique.