Materials Research in the Information Age

The availability of materials and manufacturing processes shapes society, in particular its tools and infrastructures, and has had a tremendous influence on the evolution of humankind. This is reflected by the fact that important eras of human development are named after the advanced materials introduced at a certain time, the Stone Age, Copper Age, Bronze Age, Iron Age, Glass Age, and Silicon Age. This strong influence of introducing new substances and compounds, or substantially improving their properties, is likely to continue – also in the future advanced materials will enable the evolution and integration of our society. In this special issue of Advanced Materials, we reflect on recent progress of materials research with a collection of 27 articles from the Karlsruhe Institute of Technology (KIT) providing a glimpse of this ongoing research activity worldwide. Many research groups contribute to materials research at KIT, The Research University in the Helmholtz Association. The activities of individual groups are complemented by efforts of Helmholtz research programs, in particular Science and Technology of Nanosystems (STN) and BioInterfaces in Technology and Medicine (BIFTM), as well as a number of joint research efforts funded by the German Science Foundation (DFG), the German Secretary for Education and Science (BMBF), and the European Union (EU). This fairly large number of projects on all scales, from individual grants to large efforts with hundreds of principle investigators, results in a diverse and broad spectrum of efforts in materials science. Most of the colleagues contributing to this special issue are organized at the KIT center “Materials in Technology and Life Sciences”, which integrates KIT research groups from the natural sciences, engineering, and life sciences and includes ca. 2000 scientists and doctoral researchers. They all share a common interest in materials research, the development of new materials, their characterization, and application. Presently, we are at the transition to yet another age of human development, which will likely be called the Digital Era or Information Age. Digitalization and additive manufacturing are opening new opportunities for materials research and provide the basis for the fourth industrial revolution and the Internet-of-Things. The aspect of “Matter Made to Order” is illustrated on the cover page of this special issue, which shows how advanced manufacturing methods including 3D laser writing and other types of additive manufacturing are used to fabricate rather diverse complex hybrid devices from atomic or molecular subunits. The constituent building blocks in the upper part of the cover page may consist of single atoms, clusters, molecules or larger molecular fragments, like in DNA or in polymers. By sophisticated processes, often computer-controlled, the building blocks are assembled to yield devices for various applications of ever-increasing complexity and functionality. Further development of this assembly process is the main target of the DFG-funded Excellence Cluster “3D Matter Made to Order”, which was awarded jointly to KIT and Heidelberg University last year. An overview of novel methods for 3D printing of soft matter is provided by Kadic and co-workers (article number 1807742), whereas, the foundations for 3D printing of hard materials, in particular glass, is described by Rapp and co-workers (article number 1805982). The additive automated manufacturing is not restricted to fabricating devices, but also to the synthesis of organic compounds with specific functionality, as demonstrated in the report by Breitling and co-workers (article number 1806656). The development and application of novel scale-bridging simulations methods will be the focus of a new interdisciplinary graduate school that integrates Ph.D. students from mathematics, the natural sciences, and engineering, which will start in 2019. These methods are taken up in the initiative “Virtual Materials Design”, which started in 2017 at KIT and will continue as a Helmholtz-wide national research activity until 2027. Traditional materials-discovery strategies are increasingly complemented by information-based methods, including deep learning and artificial intelligence. Methods stemming from artificial intelligence promote new developments, which may have a pronounced impact on material science. Lahann and co-workers (article number 1806898) provide an example for the application of these methods to the automated recognition of biomolecules on a wide range of substrates. Very often, advancing existing or creating new 3D manufacturing methods requires novel types of materials. One approach in this direction is the development of tailor-made, sequence-controlled polymers. Such efforts are one aspect for the research effort in the Collaborative Research Centre SFB 1176 “Molecular Structuring of Soft Matter”. This DFG-funded initiative focuses on sequence-controlled polymers, examples of which are discussed Barner-Kowollik and Meier (article number 1806027). A second, more general overview on polymer science is provided in the contribution by Théato and co-workers (article number 1806334). The development of integrated methods to characterize complex polymers is discussed in the contribution by Wilhelm and Abbasi (article number 1806484). A new class of porous, metal–organic polymers, also referred to as metal–organic frameworks (MOFs), has recently started to attract attention. Surface-mounted metal–organic frameworks (SURMOFs) are emerging as promising materials for a variety of different applications, including lithography, as reported by Wöll and Heinke (article number 1806324). This class of materials spans a huge chemical space; the number of known compounds already exceeds 100 000. Rapid progress in this area requires the application of suitable simulation methods, as discussed by Schug and co-workers (article number 1901744). Overall simulation emerges as an increasingly viable tool rationalize the experimental findings and to develop new strategies for further improvement of materials, as described by Wang and co-workers (article number 1806733). Wenzel and co-workers (article number 1808256) address emergent techniques for rational materials design for organic electronics and organic photovoltaics. In the context of the highly interesting field of biologization, researchers identify and exploit biological principles to create novel biohybrid or inorganic materials systems. Important aspects of this research direction are discussed by Hippler and co-workers (article number 1808110) as well as Levkin and co-workers (article number 1807333) developing hydrogels as smart responsive materials adapting to various stimuli. Niemeyer and Hu (article number 1806294) discuss the state of the art and perspectives with regard to the exploitation of DNA self-assembly to manufacture stable and programmable units for various applications. Complementary to these molecular routes to fabricate novel materials, inorganic clusters are emerging as interesting new compounds for additive manufacturing, as discussed by Hahn and co-workers (article number 1806634) and Hudry and co-workers (article number 1900623). A related class of novel inorganic materials with huge potential in a rather different application fields is high-entropy materials, as discussed in the contribution from Breitung (article number 1806236). Behrens and co-workers (article number 1807381) highlight the crucial importance of inorganic clusters aspects for the field of heterogeneous catalysis. Aghassi and co-workers (article number 1806483) discuss the perspectives and challenges to print electronic devices fully from inorganic precursors. Gumbsch and co-workers (article number 1806705) discuss the underlying mechanisms of the behavior of inorganic materials under mechanical load in their perspective on the microscopic mechanism of friction. Improved control over functional interfaces offers exciting opportunities to develop new materials for information processing, as reported by Molinari and co-workers (article number 1806662) regarding composite magnetoelectric materials. Taken to the ultimate limit, single-transition-metal complexes can also be exploited as the fundamental units of future quantum-based computing and simulation techniques, as discussed by Ruben and Wernsdorfer (article number 1806687). Colsmann and co-workers (article number 1806661) give a perspective on the exploitation of perovskites in the fabrication of high-performance solar cells. A promising process to fabricate such devices by printing is described in the contribution by Lemmer and co-workers (article number 1806702). Heske and co-workers (article number 1806660) review techniques of synchrotron-based photoelectron spectroscopy with a particular emphasis on characterization of materials and devices for energy conversion. Complementary to energy conversion, KIT strives to meet the materials challenges of next-generation energy-storage devices. The DFG-funded Excellence Cluster POLiS on post-lithium batteries (together with the University of Ulm) is a focal point of this activity, aspects of which are discussed in the overviews by Fichtner and co-workers (article number 1806599) and Janek and co-workers (article number 1900985). Beyond the scientific impact, images of conventional and new materials recorded with a variety of techniques can also be very appealing from a purely esthetic point of view. This is demonstrated by the back cover (see Figure 1), which provides a collage of several microscopy images or photographs highlighting some of the materials presented in this issue. In order to aid the reader in finding the related article, a scheme is provided at the end of this editorial. The guest editors would like to acknowledge Dr. Nathalie Matter-König for her highly capable and patient support in putting together this special issue.