Perovskite materials - Page 14

University of Alberta scientists have found calcium silicate perovskite at Earth's surface. "Nobody has ever managed to keep this mineral stable at the Earth's surface," said Graham Pearson, a professor in the University of Alberta's Department of Earth and Atmospheric Sciences and Canada Excellence Research Chair Laureate. He explained the mineral is found deep inside Earth's mantle, at 700 kilometers.

"The only possible way of preserving this mineral at the Earth's surface is when it's trapped in an unyielding container like a diamond," he explained. "Based on our findings, there could be as much as zetta tonnes (10²¹) of this perovskite in deep Earth".

Oxford Photovoltaics announced that it was working with scientists at the new Helmholtz-Zentrum Berlin (HZB) innovation lab to further the optimization of its perovskite cell materials for silicon heterojunction solar cell technology.

The new partnership with HZB aims at furthering commercialization efforts with greater leverage of HZB's silicon cell material knowledge and specifically heterojunction cells. 'Working with HZB to understand solar cell manufacturers' silicon cells, will allow Oxford PV's perovskite on silicon tandem formation to be fully optimized, to ensure the most efficient tandem solar cell, and the easy transfer of our technology into our commercial partner's industrial processes", commented Chris Case, Chief Technology Officer, at Oxford PV. 'Oxford PV is now in the final stage of commercializing its perovskite photovoltaic solution, which has the potential to enable efficiency gains that will transform the economics of silicon photovoltaic technology globally.'

Researchers at the University of Toronto in Canada and ShangaiTech University in China have succeeded in using colloidal quantum dots in a high-mobility perovskite matrix to make a near-infrared (NIR) light-emitting diode (LED) with a record electroluminescence power conversion efficiency of nearly 5% for this type of device. The NIR LED could find use in applications such as night vision devices, biomedical imaging, optical communications and computing.

The researchers say that they may have found a way to overcome the known problem of low power conversion efficiencies (PCEs) of CQD-based LEDs, by embedding CQDs in a high-mobility mixed-halide perovskite matrix. The new composite allows for radiative recombination in the quantum dots by preventing charge carriers from becoming trapped in defects as they travel through the material, and this without increasing the turn-on voltage in a device. By carefully engineering the composition of the mixed halide matrix, the researchers made bright NIR CQD LEDs with electroluminescence PCEs of 4.9%. This value is said to be more than twice that of previously reported values for devices made from these materials, which means that with same amount of electricity it is possible to get twice as much NIR light power out.

Researchers at the Department of Energy's Lawrence Berkeley National Laboratory have succeeded in growing atomically thin 2D sheets of organic-inorganic hybrid perovskites from a solution. The sheets are claimed to be of high quality and large in area.

The scientists state that this is the first example of 2D atomically thin nanostructures made from ionic materials and that the results of this study open up opportunities for fundamental research on the synthesis and characterization of atomically thin 2D hybrid perovskites and introduce a new family of 2D solution-processed semiconductors for nanoscale optoelectronic devices, such as field effect transistors and photodetectors.