Perovskite, Potential Solar Cell Material Unsuited for Real-World Use

By Becky Oskin

Solar cells made from perovskites have sparked great excitement in recent years because the crystalline compounds boast low production costs and high energy efficiencies. Now UC Davis scientists have found that some promising compounds — the hybrid lead halide perovskites — are chemically unstable and may be unsuited for solar cells.

“We have proven these materials are highly unlikely to function on your rooftop for years,” said Alexandra Navrotsky, interdisciplinary professor of ceramic, earth, and environmental materials chemistry at UC Davis and director of the Nanomaterials in the Environment, Agriculture, and Technology (NEAT) organized research unit.

Livestock and Climate Change: Facts and Fiction

Dairy cows eat hay

Holstein cows eat lunch at the Dairy Cattle Facility at UC Davis. Credit: Gregory Urquiaga, UC Davis

By Frank Mitloehner

As the November 2015 Global Climate Change Conference COP21 concluded in Paris, 196 countries reached agreement on the reduction of fossil fuel use and emissions in the production and consumption of energy, even to the extent of potentially phasing out fossil fuels out entirely.

Both globally and in the U.S., energy production and use, as well as the transportation sectors, are the largest anthropogenic contributors of greenhouse gasses (GHG), which are believed to drive climate change. While there is scientific consensus regarding the relative importance of fossil fuel use, anti animal-agriculture advocates portray the idea that livestock is to blame for a lion’s share of the contributions to total GHG emissions.

Magneto-ionics could be a new alternative to electronics

Our electronic devices are based on what happens when different materials are layered together: “The interface is the device,” as Nobel laureate Herbert Kroemer famously claimed over 40 years ago. Right now, our microchips and memory devices are based on the movement of electrons across and near interfaces, usually of silicon, but with limitations of conventional electronics become apparent, researchers are looking at new ways to store or process information. These “heterostructures” can also find applications in advanced batteries and fuel cells.

Now physicists at UC Davis have observed what’s going on at some of these interfaces as oxygen ions react with different metals, causing drastic changes in magnetic and electronic properties.

Engineering new routes to biochemicals

Living cells can make a vast range of products for us, but they don’t always do it in the most straightforward or efficient way. Shota Atsumi, a chemistry professor at UC Davis, aims to address that through “synthetic biology:” designing and building new biochemical pathways within living cells, based on existing pathways from other living things.

Engineered bacteria use both glucose and acetate, instead of just glucose, as raw material to make isobutyl acetate, which can be used in chemical manufacturing and as fuel.

Engineered bacteria use both glucose and acetate, instead of just glucose, as raw material to make isobutyl acetate, which can be used in chemical manufacturing and as fuel.

UC Davis plans joint research with Brazil

FAPESP, the São Paulo Research Foundation and UC Davis announced May 12 the launch of a new program to strengthen collaborative research in physical sciences, engineering, biomedical sciences and agriculture within the framework of the cooperation agreement signed by the two institutions in 2012.

The announcement was made during the opening of FAPESP Week UC Davis in Brazil, a two-day event attended by 26 scientists from UC Davis and institutions in São Paulo State to present research findings in a range of knowledge areas. The event is a follow-up to FAPESP Week California, held in November 2014 at UC Davis and UC Berkeley in the United States.

New X-ray technique for surfaces

Surfaces are very interesting to material scientists. The reactions that happen at the point where inside and outside meet, and elements interact with other chemicals or radiation, are important for developing new technology for batteries, fuel cells or photovoltaic panels, for catalysts for the chemical industry, and for understanding environmental chemistry and pollution. Now researchers at UC Davis and the Advanced Light Source at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory have combined two existing methods techniques to come up with a new method for studying surfaces with X-rays. This new technique is called SWAPPS, for Standing Wave Ambient Pressure Photoelectron Spectroscopy.

Modeling of silicon nanoparticles for solar energy

Silicon nanoparticles embedded in a zinc sulfide matrix are a promising material for new types of solar cell. Computational modeling by Stefan Wipperman, Gergely Zimanyi, Francois Gygi and Giulia Galli at UC Davis and colleagues shows how such a material might work.

“Designing materials with desired properties for renewable energy application is a topic of great current interest in physics, chemistry, and materials science, and one of the goals of the Materials Genome initiative, launched in the US in 2011. Our paper focuses on the search for design rules to predict Earth abundant materials for the efficient conversion of solar energy into electricity,” Zimanyi said in an email.

Honda Smart Home Open House is March 25

There will be a community open house at the Honda Smart Home in West Village on campus next Tuesday afternoon, March 25, noon to 4 p.m.. If you’ve been wondering what this zero-net energy smart home is all about, this is your chance to tour the home, talk to project leaders and learn more about it.

The house is on N. Sage Street in West Village, a block north of the village square.

The event is free and open to the public.

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UC Davis student team selected for national solar competition

A team of students from UC Davis has been selected to compete in the U.S. Department of Energy Solar Decathlon 2015. As competitions go, it’s a marathon, not a sprint: the  teams will have until Fall, 2015 to design, build and test their solar-powered homes at the test site at UC Irvine.

“Our team is very excited at the opportunity to compete in the Solar Decathlon in 2015. We plan to build an affordable zero net energy house that will serve as a prototype for commercialization of housing units for transient populations in the U.S.,” said Professor Frank Loge of the UC Davis Department of Civil and Environmental Engineering, who is coordinating the project, via e-mail.

Probing hydrogen catalyst assembly, part II

Biochemical reactions sometimes have to handle dangerous things in a safe way. New work from researchers at UC Davis and Stanford University shows how cyanide and carbon monoxide are safely bound to an iron atom to construct an enzyme that can generate hydrogen gas. The work is published Jan. 24 in the journal Science.

Producing hydrogen with catalysts based on abundant metals, such as iron, is key to hopes of using hydrogen to replace carbon-based fuels. But before you can make hydrogen, you have to make the catalyst that enables the reaction –something bacteria have been able to do for millennia.