The regime of mesoscale science, where the granularity of atoms and quantization of energy gives way to apparently continuous and infinitely divisible matter and energy, yields strikingly complex architectures, phenomena, and functionalities that control macroscopic material behavior. Research in mesoscale materials and chemical science is an opportunity space for next-generation discovery, science, technology, and innovation, with promise of new solutions for societal problems such as energy, environment, climate, advanced manufacturing, and economic growth.

Colloidal nanocrystals can combine the benefits of inorganic semiconductors with size-tunable electronic structure and inexpensive solution-based device fabrication. Single- and multicomponent nanocrystal assemblies, also known as superlattices, provide a powerful general platform for designing two- and three-dimensional solids with tailored electronic, magnetic, and optical properties. Such assemblies built of “designer atoms” can be considered as a novel type of condensed matter, whose behavior depends both on the properties of individual building blocks and on the interactions between them. Efficient charge transport is crucial for applications of nanocrystal-based materials in various electronic and optoelectronic devices. For a long time, nanocrystals were considered poor electronic conductors. To facilitate charge transport, we developed novel surface chemistry using all-inorganic ligands, namely metal chalcogenide complexes that transformed colloidal nanomaterials into a very competitive class of solution-processed semiconductors for electronic, thermoelectric, and photovoltaic applications.

This article reviews the use of scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to characterize the physical and electronic properties of epitaxial graphene. Topographical variations revealed by STM allow the determination of the number of graphene layers and the detection of lattice mismatch between the graphene and the substrate, as well as rotational disorder. STS allows the local electronic characterization of graphene. STM/STS can also be used to perform local studies of graphene modification through processes such as atomic/molecular adsorption and intercalation.

Materials play a major role in defining the sustainability performance of automobiles throughout their materials-production, manufacturing, use, and end-of-life stages. Materials production and manufacturing raise many sustainability issues, including resource scarcity and materials sourcing, energy and carbon intensity, and materials efficiency in parts fabrication. In the use stage, materials properties such as density and strength directly affect materials-mass requirements, which influence two dominant sustainability parameters for vehicles: fuel economy and service life. For conventional vehicles, the operation segment of the use stage accounts for about 85% of the total life-cycle energy consumption and greenhouse-gas emissions. Consequently, powertrain technologies and efficiencies as well as fuel-cycle processes control these impacts. Future trends in vehicle electrification will shift the magnitude and distribution of life-cycle impacts and the effectiveness of materials strategies for improving sustainability, such as lightweighting. In many cases, the materials-production stage could become a greater determinant in life-cycle impacts. With current vehicle end-of-life management infrastructure, 85% of materials are recyclable, but recovery of plastics and segregation of metal alloys represent opportunities for improvement. Life-cycle assessment and cost analysis provide the most comprehensive methods for evaluating the sustainability of materials strategies. Using a life-cycle framework, this article highlights the current and future materials challenges and opportunities driving vehicle sustainability performance.

From the earliest days of graphene electronics, epitaxial graphene grown on SiC has been the focus of both academic and industrial research because it is potentially scalable to large electronic systems. Yet, epitaxial graphene electronics is still in its infancy. In the race to demonstrate devices, the fundamental work of understanding and controlling this material has just begun. It is entirely possible that graphene’s potential for electronics lies in new ways of thinking about electronics. In that case, significant advances will come only after serious materials physics and engineering research. One of the arguably most important properties of epitaxial graphene is that it can be studied with a variety of analytical probes beyond electron-transport measurements. Synchrotron studies have been key to understanding a wide variety of properties, including the role of the graphene–SiC interface in graphene’s transport properties, how the films are doped, whether and how a bandgap (critical to digital electronics) can be formed, and how metals and insulators can be grown on graphene for critical ohmic contacts and gate structures. These important studies are discussed in this review.