Comment

The steel industry in China has an important role in reducing national and global carbon emissions, demanding integrated actions and efforts across policies, industry and science to achieve the goal of carbon neutrality.

The success of silicon photonics is a product of two decades of innovations. This photonic platform is enabling novel research fields and novel applications ranging from remote sensing to ultrahigh-bandwidth communications. The future of silicon photonics depends on our ability to ensure scalability in bandwidth, size and power.

Organic semiconductors based on molecular or polymeric π-conjugated systems are now used at scale in organic light-emitting diode (OLED) displays and show real promise in thin-film photovoltaics and transistor structures. Here, we address recent progress in understanding and performance for OLEDs and for organic photovoltaics.

Metal–organic frameworks, porous coordination network materials constructed with metal ions and organic molecules, have grown over the past 20 years into an innovative chemistry that has contributed to solutions for the problems faced by humanity in the environment, resources, energy and health.

Soft matter has evolved considerably since it became recognized as a unified field. This has been driven by new experimental, numerical and theoretical methods to probe soft matter, and by new ways of formulating soft materials. These advances have driven a revolution in knowledge and expansion into biological and active matter.

Materials and surface sciences have been the driving force in the development of modern-day lithium-ion batteries. This Comment explores this journey while contemplating future challenges, such as interface engineering, sustainability and the importance of obtaining high-quality extensive datasets for enhancing data-driven research.

Semi-synthetic goldilocks material design integrates the tunable characteristics of synthetic materials and the refined complexity of natural components, enabling for the progress of biomaterials across length scales. Accelerated translational success may thus be possible for more personalized and accessible products.

Structural materials are critical components for our daily lives and industries. This Comment highlights the emerging concepts in structural materials over the past two decades, particularly the multi-principal element alloys, heterostructured materials and additive manufacturing that enables the fabrication of complex architectures.

Quantum materials show emergent electronic properties and related functions that are profoundly described by quantum mechanics beyond the semi-classical picture of electrons. Here, key developments and progress in the last two decades are surveyed and future challenges outlined.

Twentieth-century utopian visions of a space-age future have been eclipsed by dystopian fears of climate change and environmental degradation. Avoiding such grim forecasts depends on materials innovation and our ability to predict and plan not only their behaviour but also their sustainable manufacture, use and recyclability.

Synthetic stimuli-responsive systems have become increasingly sophisticated and elegant at the nanoscale. This Comment discusses how rationally designed molecular systems capable of dynamic motions can be deployed in macroscopically porous metal–organic frameworks and respond to various stimuli.

Automated experiments can accelerate research and development. ‘Flexible automation’ enables the cost- and time-effective design, construction and reconfiguration of automated experiments. Flexible automation is empowering researchers to deploy new science and technology faster than ever before.

New classes of functional soft materials show promise to revolutionize robotics. Now materials scientists must focus on realizing the predicted performance of these materials and developing effective and robust interfaces to integrate them into highly functional robotic systems that have a positive impact on human life.

Strong light–matter coupling in quantum cavities provides a pathway to break fundamental materials symmetries, like time-reversal symmetry in chiral cavities. This Comment discusses the potential to realize non-equilibrium states of matter that have so far been only accessible in ultrafast and ultrastrong laser-driven materials.

Electron microscopy touches on nearly every aspect of modern life, underpinning materials development for quantum computing, energy and medicine. We discuss the open, highly integrated and data-driven microscopy architecture needed to realize transformative discoveries in the coming decade.

Classical experiments from solid-state electrochemistry can be used to determine the charge of ions in solids. This Comment also clarifies how the charge of point defects fits with the standard picture of ionic charge, and highlights differences between these electrochemical experiments and methods that probe electrons directly.

Shirakawa, MacDiarmid and Heeger received the 2000 Nobel Prize in Chemistry for the discovery of conducting polymers. Here we summarize the impact of (semi)conducting polymers on fundamental research, synthetic accessibility at scale, industrial applicability and the future.

Meteoritic diamonds and synthesized diamond-related materials contain a wide variety of complex nanostructures. This Comment highlights and classifies this structural complexity by a systematic hierarchical approach, and discusses the perspectives on nanostructure and properties engineering of diamond-related materials.

Consensus among experts is that only an effective COVID-19 vaccine will end the pandemic. This Comment focuses on how this pandemic has accelerated the development of vaccine platforms distinct from classical vaccines; these novel platforms may also increase the response time when new viruses emerge in the future.

The restoration of fire-damaged historical monuments entails a wide range of scientific questions. Taking as a starting point the case of Notre-Dame de Paris, this Comment defines the materials science challenges of post-fire restoration, and also briefly outlines the issues of structural integrity, fire safety and preservation ethics.