DoE - Page 3

The U.S. Department of Energy (DOE) announced funding of up to $130 million for new research to advance early-stage solar technologies.

This funding program targets five research areas: photovoltaics (PV), concentrating solar-thermal power (CSP), soft costs reduction, innovations in manufacturing, and solar systems integration. These projects will aim to make solar energy more affordable, reliable, and secure, while working to boost domestic solar manufacturing, reduce red tape, and make PV more resilient to cyberattack.

An international team of researchers led by the U.S. Department of Energy's SLAC National Accelerator Laboratory (that also included, among others, researchers from NIST, the University of Bath, Kings College London and Yonsei University) has gained new understanding of the movement of atoms in perovskite materials and how it affects the functioning of those materials. The results could explain why perovskite solar cells are so efficient and aid the quest to design hot-carrier solar cells, a theorized technology that would almost double the efficiency limits of conventional solar cells by converting more sunlight into usable electrical energy.

Common materials that make up conventional solar cells display a nearly rigid arrangement of atoms with little movement. In hybrid perovskites, however, the arrangements are more flexible and atoms move around more freely, an effect that impacts the performance of the solar cells but has been difficult to measure.

Ascent Solar Technologies, a manufacturer of flexible thin-film photovoltaic (PV) solutions, has been selected by the US Department of Energy (DOE), supported by the Office of Technology Transitions (OTT) Technology Commercialization Fund (TCF), for two exclusive development projects.

As part of the awards, worth up to $100,000 each, Ascent Solar is to work towards commercialization of sputtered Zn(O,S) buffers in flexible CIGS solar cells and also development of next-generation, high-efficiency Perovskite/CIGS tandem cell. These projects are part of Ascent Solar's plans for next-generation lightweight and flexible solar cells.

In a work supported by the Department of Energy (DOE) and Office of Science, Basic Energy Sciences (BES), researchers from Stanford, University Pennsylvania, SLAC National Accelerator Lab, Columbia University, Carnegie Institute for Science in Washington and Weizmann Institute of Science in Israel, have shown how atoms in perovskites respond to light and could explain the high efficiency of these perovskite-based solar cells.

The team explains that sunlight causes large changes to the underlying network of atoms that make up perovskites. Before being hit with light, six iodine atoms rest around a lead atom. Within 10 trillionths of a second after being hit with light, the iodine atoms whirl around each lead atom. These first atomic steps distort the structure and result in significant changes. Furthermore, the atoms' motions alters the way electricity flows and may help explain the efficiency of perovskites in solar cells.

Lawrence Berkeley National Laboratory (Berkeley Lab) researchers have manipulated the chemical structure of perovskite so that the material turns from transparent to opaque when heated and also converts sunlight into electricity. This ability may lead to applications like windows that automatically tint on a sunny day to block the heat while also generating electricity, power-producing smart windows for buildings, cars and display screens, and more.

While the sunlight conversion efficiency of the material (an inorganic halide perovskite with added cesium, lead, iodine and bromine) is still low and the transition from transparent window to opaque solar cell requires heating the window to the boiling point of water, the team is already working on versions that work at lower temperatures and with higher conversion efficiency. The new material is reportedly able to retain its conversion efficiency after many cycles between transparent and a reddish tint.

A team at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have developed a novel perovskites and CNTs-based demonstration device that responds to sunlight by transforming from transparent to tinted while converting sunlight into electricity.

A switchable photovoltaic window

The thermochromic windows technology responds to heat, as was said, by transforming from transparent to tinted. As the window darkens, it generates electricity. The color change is driven by molecules (methylamine) that are reversibly absorbed into the device. When solar energy heats up the device, the molecules are driven out, and the device is darkened. When the sun is not shining, the device is cooled back down, and the molecules re-absorb into the window device, which again appears transparent.

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory, in collaboration with Brookhaven National Laboratory and three universities, have conducted a study that combined supercomputer simulation and X-ray characterization of a unique peroskite material that gradually "forgets", like the human brain, and could one day be used for advanced bio-inspired computing.

The material in the study, called a quantum perovskite, offers researchers a simpler non-biological model of what "forgetfulness" might look like on an electronic level. The perovskite shows an adaptive response when protons are repeatedly inserted and removed that resembles the brain's desensitization to a recurring stimulus.

Researchers at the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) developed a new perovskite ink with a long processing window that allows the scalable production of perovskite solar cells.

To create a perovskite film, a coating of chemicals is deposited on a substrate and heated to fully crystalize the material. The various steps involved often overlap with each other and complicate the process. One extremely critical stage requires the addition of an antisolvent that extracts the precursor chemicals, and thus create crystals of good quality. The window for this step opens and closes within seconds, which is detrimental for manufacturing due to the precision required to make this time window. NREL researchers were able to keep that window open as long as 8 minutes.

Department of Energy (DoE) funded researchers investigated the electronic properties of 2D hybrid organic-inorganic perovskite sheets, as an alternative to graphene and other materials. The researchers reported that such perovskites could rival graphene in PV applications, since the 2D crystals exhibited efficient photoluminescence, were easier to grow than graphene and it's possible to dope it to make the various varieties of ionic semiconductors needed to beat other 2D materials with tunable electronic/photonic properties.

Scientists created these new forms of hybrid organic-inorganic perovskites in atomically thin 2D sheets and first showed how they hold promise as semiconductor materials for photovoltaic applications. Next they showed how they could serve as an alternative to other 2D semiconductors that are widely studied as potential successors to silicon in future electronic devices.

Scientists at the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL), in collaboration with researchers at Shanghai Jiao Tong University (SJTU), have reportedly devised a method to improve perovskite-based solar cells, making them more efficient and reliable with higher reproducibility.

The research was funded by the DOE's SunShot Initiative. It involved hybrid halide perovskite solar cells and revealed treating them with a specific solution of methyl ammonium bromide (MABr) would repair defects, improving efficiency. The scientists converted a low-quality perovskite film with pinholes and small grains into a high-quality film without pinholes and with large grains. This apparently boosted the efficiency of the perovskite film in converting sunlight to 19%, according to NREL.