Perovskites, mineral materials composed of calcium titanate, have been found to be valuable for the fabrication of high-performance solar cells. While teams of scientists and engineers worldwide have been developing and testing perovskite solar cells in laboratory settings, large-scale outdoor evaluations of these cells are still lacking.

Researchers at University of Rome Tor Vergata, the Hellenic Mediterranean University in Crete, BeDimensional S.p. A., Great Cell, the Italian Institute of Technology (IIT) and University of Siena have recently manufactured large-area perovskite solar panels engineered using two-dimensional (2D) materials. They then successfully integrated 9 of these solar panels into a stand-alone solar farm, located on the Greek island of Crete. This team’s findings, presented in a paper published in Nature Energy, could facilitate and inform the future large-scale implementation of perovskite solar cells.

“Our recent paper highlights our joint research efforts for the last 5 years in the upscaling of perovskite PVs, starting from lab cells to modules, panels and finally to a solar farm infrastructure,” Francesco Bonaccorso, one of the researchers who carried out the study, told to Tech Xplore. “This project was specifically developed in the context of the European Graphene Flagship initiative, which established a close collaboration between University Tor Vergata, BeDimensional S.p. A., GreatCell and Hellenic Mediterranean University, having both complementary and widely different skillsets.”

Inserting a metal fluoride layer in multilayered perovskite-silicon tandem solar cells can stall charge recombination and enhance performance, KAUST researchers have found.

Tandem solar cells that combine perovskite and silicon-based subcells in one device are expected to better capture and convert sunlight into electricity than their conventional single-junction silicon analogs at a lower cost. However, when sunlight strikes the perovskite subcell, the resulting pairs of electrons and positively charged holes tend to recombine at the interface between perovskite and the electron-transport layer. Also, a mismatch between energy levels at this interface hinders electron separation within the cell. Cumulatively, these problems lower the maximum operating voltage available, or open-circuit voltage, of the tandem cells and limit device performance.

These performance issues can partially be solved by introducing a lithium fluoride layer between the perovskite and electron-transport layer, which usually comprises the electron-acceptor fullerene (C₆₀). However, lithium salts readily liquify and diffuse through surfaces, which makes the devices unstable. “None of the devices have passed the standard test protocols of the International Electrotechnical Commission, prompting us to create an alternative,” says lead author Jiang Liu, a postdoc in Stefaan De Wolf’s group.

The power plant can produce 4.2 million units of power every year.

Photovoltaics will play a key role in the future energy supply. Conventional solar cells based, for instance, on silicon, a well-known semiconductor material, are already highly developed and in widespread use. However, their production is complex because it requires a high vacuum with high temperatures. It can take up to five years for the energy used for production to be offset by operation.

This is where solar cells based on organic semiconductors can make a difference, as they can be printed in an energy-and cost-saving way. However, there are limitations to the energy conversion that need to be examined in more detail. A research team led by the Professorship of Optics and Photonics of Condensed Matter at Chemnitz University of Technology has investigated which main factors are decisive for the power limitation of organic solar cells.

The lead author of the study is Christopher Wöpke, research associate at the Professorship of Optics and Photonics of Condensed Matter at Chemnitz University of Technology. He was joined in the study by scientists from the universities of Bayreuth, Bern (CH), Durham (UK), Erlangen-Nuremberg and the Advanced Light Source Berkeley Lab (U.S.). Among other things, the team found that transport resistance in particular severely limits the performance of organic solar cells.

Nestled in deep woods in Jefferson, Kim and Rusty Fenn live off the grid in a home they built themselves out of wood from their property. They have two solar-power systems on their roof, one to generate electricity and one to heat their water.

They have all the appliances any home would want, and the solar power provides all their needs. They heat with a heat pump and a wood stove.

Kim, the creative one of the couple, had a pile of chicken grain bags, and decided to make a bag out of one. She then made a bunch for Christmas presents for friends and family. They were such a hit, that the couple decided to make them commercially.