Catalyst design and optimization are central to advancing catalytic science. In both enzymatic and homogeneous systems, the microenvironment that creates distinct spatial and electronic configurations around active sites showcases profound influence on catalytic behavior. However, elucidating microenvironment modulation (MEM) in heterogeneous catalysts remains a significant challenge, primarily due to the structural rigidity and limited tailorability of conventional solid materials. Reticular materials, including metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), have recently emerged as prominent candidates for heterogeneous catalysis. Their atomic-level structural precision and high degree of tunability render them ideal model systems for MEM around catalytic sites. As such, MOFs and COFs offer unique opportunities to unravel the role of MEM in governing catalytic performance. In this presentation, I will highlight our recent progress in leveraging MEM surrounding catalytic sites based on reticular materials for improving catalysis.

This video article highlights the recent works by Prof. Kaihui Liu’s group at Peking University in making wafer-scale 2D semiconductor thin films. In contrast to conventional epitaxial surface growth methods, they have developed two novel epitaxial interface growth methods, which have enabled them to make various 2D semiconductors in wafer scale for device fabrication. As exemplified in this video highlight, using the novel interfacial lattice-epitaxy growth method, they have successfully made single-crystal 4-cm wafers of MoS₂, with a thickness ranging from 1 to ~1500 layers, of high crystallinity and uniformity. Furthermore, they fabricated mono-, bi-, and tri-layer MoS₂ transistors, whose electrical performance exceeds the IRDS 2028 mobility target. Also, using the interfacial solid-liquid-solid growth method, they have made single-phase single-crystal 5-cm wafers of InSe multilayer films and fabricated integrated circuits of transistor arrays with a performance matrix surpassing the Si Intel 3nm technology.

The author highlights his group's research, focusing on developing high-efficiency and stable perovskite light-emitting diodes (PeLEDs), with particular emphasis on exploring a new approach to improve the efficiency and lifetime through a “weak space-confinement” strategy. Although the conventional “strong space-confinement” strategy can improve emission efficiency, it also leads to severe Auger recombination and ion migration, resulting in low brightness and poor device stability of perovskite LEDs. Moreover, the commonly used organic ligands in such systems exhibit poor thermal stability and cannot withstand Joule heating during device operation, thereby limiting the long-term stability. To overcome these challenges, hypophosphorous acid (HPA) and ammonium chloride (NH₄Cl) were introduced into the CsPbBr₃ precursor system to regulate the crystallization process. This approach yielded highly crystalline perovskite films with large grain size and low grain-boundary density. The weakly space-confined perovskite films show suppressed Auger recombination, reduced ion migration, and enhanced thermal stability. Based on this design, the fabricated green PeLEDs achieved an external quantum efficiency (EQE) of 22%, a maximum brightness of 1.16×10⁶ cd m^-2, and an extrapolated lifetime of 1.85×10⁵ hours at 100 cd m^-2. These results represent a significant breakthrough in both brightness and stability, providing a promising pathway toward the practical application of perovskite LEDs.

Electron-electron interactions can be significant in graphene with an ABC-stacking sequence. By developing innovative experimental techniques, we successfully fabricated high-quality ABC-stacked multilayer graphene and observed a correlated insulating state at charge neutrality, beginning with ABCA-tetralayer. Furthermore, by introducing proximity-induced spin-orbit coupling, at the charge neutrality point of ABCA-tetralayer, we achieved a topological Chern insulator with a layer-number-dependent Chern number of four.

Elementary Particle Physics and General Relativity relate respectively to the very small and the very large. But they are both essential in trying to understand the structure of the universe, especially at the very first instants. Some of the key ideas involved in this juncture of the very small and the very large are illustrated.

Electronic states at surfaces, interfaces, and edges of materials emerge due to different reasons and have their own characters, which are expected to be useful for intriguing physics and possible applications to electronic/spintronics devices. Especially emerging quantum materials, such as graphene and similar monatomic-layer materials, van der Waals two-dimensional crystals, and topological insulators, show prominent features in the surface/edge states. Such states at the boundaries are different from those inside the three- or two-dimensional crystals, because of the truncation of crystal lattice periodicity, space-inversion-symmetry breaking, and difference in topology in band structures across the boundaries. Such quantum materials are expected to be key ingredients for energy-saving/-harvesting technology as well as quantum computation/information technology. This is based on exotic phenomena at the states, such as spin–momentum locking of electrons, dissipation-less charge/spin currents, nonreciprocal current, and possible Majorana fermions. In this presentation, the fundamental concepts of such surface/edge states are introduced from the viewpoint of surface physics. Especially charge and spin-related transport properties are discussed based on controls of the atomic and electronic structures of materials by using state-of-the-art techniques.

We introduce experimental investigations on the high T_c superconductivity at 80 K in the bilayer nickelate La₃Ni₂O₇ under a 14 GPa pressure. The superconductivity emerges coincidently with a structural transition from Amam to I4/mmm. Both zero resistance and diamagnetic response, which are essential for superconductivity, were observed. A multislice electron ptychography technique was employed to visualize the oxygen. The results confirm the superconducting phase is the bilayer phase of La₃Ni₂O₇ with low oxygen vacancies.

Crystal structure prediction has long fascinated scientists. There has been intense investigation over the last century ranging from simplistic rules to data-driven predictions and, most recently, generative artificial intelligence tools developed by academics and now deployed at scale by private companies like DeepMind. The author describes the timeline of crystal structure prediction and how machine learning has supplemented and, in some cases, replaced traditional approaches. The video article compares generative models including variational autoencoders, generative adversarial networks, and diffusion models and describes new efforts to condition these models to achieve inverse design of new crystal structures. Specific examples of xtal2png and CrysTens representations were given.

The Standard Model of particle physics (SM) and Einstein general relativity are extremely successful in describing almost all phenomena observed in Nature so far, spanning distances from a fraction of Fermi to thousands of megaparsec (Mpc). In this review article, the author deliberates on the question formulated in the title, given that the SM does not allow neutrino oscillations, does not have a candidate for dark matter in the Universe, and does not explain the observed cosmological dominance of matter over antimatter.

In this video article the author covers the history and current status of ground-based gamma-ray astronomy. The recent results in this field have brought important implications to various aspects in astrophysics, such as cosmic ray science and black holes and dark matters, and thus advanced our understanding of the dynamic non-thermal universe. The author also discusses the future prospects in this field, especially the possible imaging air Cherenkov telescopes in GeV energy range.