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A research team from KTH Royal Institute of Technology and Max Planck Institute of Colloids and Interfaces reports to have found the key to controlled fabrication of cerium oxide mesocrystals. The research is a step forward in tuning nanomaterials that can serve a wide range of uses—including solar cells, fuel catalysts and even medicine.

Mesocrystals are nanoparticles with identical size, shape and crystallographic orientation, and they can be used as building blocks to create artificial nanostructures with customized optical, magnetic or electronic properties. In nature, these three-dimensional structures are found in coral, sea urchins and calcite desert rose, for example. Artificially-produced cerium oxide (CeO₂) mesocrystals—or nanoceria—are well-known as catalysts, with antioxidant properties that could be useful in pharmaceutical development.

“To be able to fabricate CeO₂ mesocrystals in a controlled way, one needs to understand the formation mechanism of these materials,” says Inna Soroka, a researcher in applied physical chemistry at KTH. She says the team used radiation chemistry to reveal for the first time the ceria mesocrystal formation mechanism.

Over the past decades, engineers have created increasingly advanced and highly performing integrated circuits (ICs). The rising performance of these circuits in turn increased the speed and efficiency of the technology we use every day, including computers, smartphones and other smart devices.

To continue to improve the performance of integrated circuits in the future, engineers will need to create thinner transistors with shorter channels. Down-scaling existing silicon-based devices or creating smaller devices using alternative semiconducting materials that are compatible with existing fabrication processes, however, has proved to be challenging.

Researchers at Purdue University have recently developed new transistors based on indium oxide, a semiconductor that is often used to create touch screens, flatscreen TVs and solar panels. These transistors, introduced in a paper published in Nature Electronics, were fabricated using atomic layer deposition, a process that is often employed by transistor and electronics manufacturers.

Materials scientists at the UCLA Samueli School of Engineering and colleagues from five other universities around the world have discovered the major reason why perovskite solar cells—which show great promise for improved energy-conversion efficiency—degrade in sunlight, causing their performance to suffer over time. The team successfully demonstrated a simple manufacturing adjustment to fix the cause of the degradation, clearing the biggest hurdle toward the widespread adoption of the thin-film solar cell technology.

A research paper detailing the findings was published today in Nature. The research is led by Yang Yang, a UCLA Samueli professor of materials science and engineering and holder of the Carol and Lawrence E. Tannas, Jr., Endowed Chair. The co-first authors are Shaun Tan and Tianyi Huang, both recent UCLA Samueli Ph.D. graduates whom Yang advised.

Perovskites are a group of materials that have the same atomic arrangement or crystal structure as the mineral calcium titanium oxide. A subgroup of perovskites, metal halide perovskites, are of great research interest because of their promising application for energy-efficient, thin-film solar cells.

The fix could pave the way for commercialization of the high-performance, sunlight-to-electricity discovery.

In the future, decarbonized societies that use internet of things (IoT) devices will become commonplace. But to achieve this, we need to first realize highly efficient and stable sources of renewable energy. Solar cells are considered a promising option, but their electrical contacts suffer from a “tradeoff” relationship between surface passivation and conductivity. Recently, researchers from Japan have developed a new type of electrical contact that can overcome this problem.

The most recent type of commercial photovoltaic cell (solar cell) uses stacked layers of crystalline silicon (c-Si) and an ultrathin layer of silicon oxide (SiO_x) to form an electrical contact. The SiO_x is used as a “passivating” film—an unreactive layer that improves the performance, reliability, and stability of the device. But that does not mean that simply increasing the thickness of this passivating layer will lead to improved solar cells. SiO_x is an electrical insulator and there is a trade-off relationship between passivation and the conductivity of the electrical contact in solar cells.

In a new study, published in ACS Applied Nano Materials, a research team led by Assistant Professor Kazuhiro Gotoh and Professor Noritaka Usami from Nagoya University has developed a novel SiO_x layer that simultaneously allows high passivation and improved conductivity. Named NAnocrystalling Transport path in Ultrathin dielectrics for REinforcing passivating contact (NATURE contact), the new electrical contact consists of three-layer structures made up of a layer of silicon nanoparticles sandwiched between two layers of oxygen-rich SiO_x. “You can think of a passivating film as a big wall with gates in it. In the NATURE contact, the big wall is the SiO_x layer and the gates are Si nanocrystals,” explains Dr. Gotoh.

US startup company Green Hydrogen International announced plans for a a 60GW renewable H₂ project that will be powered by wind and solar. It’ll also produce clean rocket fuel for SpaceX, which is helmed by billionaire Tesla CEO Elon Musk, according to a report published yesterday in Recharge.

“We see Hydrogen City becoming one of the largest H₂ production centers in the world, supplying many different customers with 100% clean H₂ fuel,” founder Brian Maxwell told the energy industry pub.

The image below from GHI’s website shows the process of converting renewable energy from wind and solar farms into ammonia and rocket fuel. The key to scaling up production, the company says, is the large salt storage capability found in underground salt domes.

Engineering projects need goals, and James Worden ’89 set an especially engaging and enduring one for himself as a high school student in the early 1980s while pursuing his passion for homebuilt go-karts.

The MIT Alumni Association seeks to engage and inspire the MIT global community to make a better world. It provides a lifelong community for MIT graduates, a launching pad for students, and growing connection among MIT friends.

Circa 2020

The short-term prospects for wind and solar power look rocky amid the economic upheaval of the coronavirus. But long term, renewables could emerge stronger than ever, especially if governments integrate support for clean energy into Covid-19 economic-recovery programs.