A D V A N C E D M A T E R I A L S & P R O C E S S E S | A P R I L 2 0 2 3 1 2 MAKING FREESTANDING MEMBRANES FOR SMART MATERIALS Anewmethod formaking thin films of perovskite oxide semiconductors was created by a team of scientists and engineers from the University of Minnesota Twin Cities, Minn. The discovery will allow researchers to harness the properties of a class of smart materials and even combine them with other emerging nanoscale materials to make better devices such as sensors, smart textiles, and flexible electronics. Producing materials in thin-film form makes them easier to integrate into smaller components for electronic devices. Most thin films created via the conventional epitaxy method are stuck on their host substrate, limiting their uses. If the thin film is detached from the substrate to become a freestanding membrane, it becomes much more functional. And now, researchers have found a new way to successfully create a membrane of a particular metal oxide—strontium titanate—circumventing several issues that have plagued the synthesis of freestanding metal oxide films in the past. “We have created a process where we can make a freestanding membrane of virtually any oxide material, exfoliate it, and then transfer it onto any subject of interest we want,” says Professor Bharat Jalan. “Now, we can benefit from the functionality of these materials by combining them with other nano- scale materials, which would enable a wide range of highly functional, highly efficient devices.” umn.edu. NEW MATERIALS DISCOVERY METHOD Researchers at the DOE’s Argonne National Laboratory, Northwestern University, and the University of Chicago, all based in Illinois, developed a new method for discovering and making new crystalline materials with two or more elements. Their process yielded 30 previously unknown compounds, and ten of them have structures never seen before. The team’s invention method starts with a solution made of two components—one is a highly effective solvent that dissolves and reacts with any solids added to the solution; and the other, a less-effective solvent, tunes the reaction to produce a new solid upon addition of different elements. This tuning involves changing the ratio of the two components and the temperature, in this case ranging between 750-1300°F. EMERGING TECHNOLOGY Cornell University, Ithaca, N.Y., is leading a new $34 million research center that aims to accelerate the creation of energy-efficient semiconductor materials and technologies, and develop new approaches for microelectronics systems. The SUPeRior Energy-efficient Materials and dEvices (SUPREME) Center will bring together researchers from 14 higher education institutions, in collaboration with the center’s sponsor, Semiconductor Research Corporation. cornell.edu. BRIEF “We are not concerned with making known materials better but with discovering materials no one knew about, or theorists imagined even existed,” says Northwestern Professor Mercouri Kanatzidis. “We expect that our work will prove extremely valuable to the chemistry, materials, and condensed matter communities for synthesizing new and currently unpredictable materials with exotic properties.” This is only the beginning of what is possible since the method can be applied toalmost any crystalline solid. It can also be applied to producing many different crystal structures, including multiple stacked layers, a single layer an atom thick, and chains of molecules that are not linked. Such unusual structures have varying properties and are key to developing next-generation materials applicable to not only superconductors, but also microelectronics, batteries, magnets, and more. anl.gov. Reaction pathway from simple precursor to complex structure. The result is a layered structure with five elements— sodium, barium, oxygen, copper, and sulfur. Courtesy of Argonne National Laboratory. Professor Bharat Jalan’s team developed a newmethod for making nano-membranes of “smart” materials. Courtesy of Olivia Hultgren/UMN.
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