Researchers at the Department of Energy's Oak Ridge National Laboratory and the University of Tennessee, Knoxville, have led a study into perovskite solar cells that has revealed a way to slow phonons, the waves that transport heat.
The discovery has the potential to improve hot-carrier solar cells, which convert sunlight to electricity more efficiently than conventional solar cells by harnessing photogenerated charge carriers before they lose energy to heat.
Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have developed a new wide-bandgap perovskite layer – called Apex Flex – which they claim is able to withstand heat, light, and operational tests, and at the same time provide a reliable and high voltage.
Image from Joule
With this material, they have built tandem solar cells with 23.1% power conversion efficiency on a rigid substrate, and 21.3% on flexible plastic. The new Apex Flex wide-bandgap perovskite recombination layer is grown with atomic layer deposition (ALD). The new material is described as a “nucleation layer consisting of an ultra-thin polymer with nucleophilic hydroxyl and amine functional groups for nucleating a conformal, low-conductivity aluminum zinc oxide layer.”
Three Purdue scientists of different expertise joined forces to lead a research team – Shriram Ramanathan, professor of materials engineering; Hyowon “Hugh” Lee, assistant professor of biomedical engineering; and Alexander Chubykin, assistant professor of biological sciences.
Chubykin and Lee had been working together on new ways to sense neurotransmitters in the brain, seeking materials that could trace these chemicals with greater sensitivity and speed. Ramanathan had been working separately on just such a material for years, discovering doping methods for perovskites to be more sensitive to certain chemicals. This material – a perovskite nickelate coated with a nafion layer – turned out to be just what his colleagues were seeking. Through a series of tests, the team discovered that this material is perfect for tracking glutamate, a chemical that the brain’s nerve cells use to communicate with other cells.
Metal halide perovskites are often made by mixing cations or halides with formamidinium (FAPbI3), to get high power-conversion efficiency in perovskite solar cells. But at the same time, the most stable phase of FAPbI3 is photoinactive, meaning that it does not react to light—the opposite of what a solar power harvester should do. In addition, solar cells made with FAPbI3 show long-term stability issues. Now, researchers led by Michael Grätzel and Anders Hafgeldt at EPFL, have developed a deposition method that overcomes the formamidinium issues while maintaining the high conversion of perovskite solar cells.
In the new method, the materials are first treated with a vapor of methylammonium thiocyanate (MASCN) or formamidinium thiocyanate FASCN. This innovative tweak turns the photoinactive FAPbI3 perovskite films to the desired photosensitive ones.
University of Sydney Nano Institute will lead multi-institutional research into extending the lifetime of perovskite solar energy cells, in an effort to make them truly cost-effective.
The federal government’s renewable energy agency, ARENA, has awarded AUD$2.5 million (around USD$1,791,000) in solar energy research funding to Professor Anita Ho-Baillie, the John Hooke Chair of Nanoscience at the University of Sydney Nano Institute. The funding is part of a national injection to support solar photovoltaic research.
An experimental graphene-based perovskite solar farm has been operating in Greece for several months, and early results are said to be very promising when it comes to power output and efficiency.
Located at the Hellenic Mediterranean University in Crete and spearheaded by the EU’s Graphene Flagship, the new solar farm consists of nine graphene–perovskite panels with a total area of 4.5m2 and a total output of approximately 261 watt-peak (Wp).
Researchers at Northwestern University have developed a new method for synthesizing halide perovskite nanocrystals.
The synthesis process for the halide perovskite nanocrystal arrays. Image from Science Advances
“This method could be used to create optical displays with ‘true’ reds, greens, and blues that completely outshine current LEDs,” said Northwestern’s Chad A. Mirkin. “From color purity to pixel density, these nano-LEDs point toward a potentially dramatic improvement over current LEDs.”