The author highlights his group’s research on the mechanistic characterizations of auxin exporters and importers in plants, with particular emphasis on the structure determination of these transporters using cryo-electron microscopy (cryo-EM). Auxin, the first plant hormone to be identified, is involved in nearly all aspects of plant growth, development, and responses to environmental cues. The biological activity of auxin depends on the establishment of local concentration gradients, which are generated through the process of polar auxin transport (PAT). Members of the PIN-FORMED (PIN) protein family and the AUXIN1/LIKE-AUXIN1 (AUX1/LAX) family are key components of PAT, mediating cellular auxin efflux and influx, respectively. Using cryo-EM single particle analysis, high-resolution structures of PIN1 and AUX1 were determined, revealing the overall architecture of each transporter as well as their modes of auxin and inhibitor binding. Biochemical analyses further demonstrated distinct transport mechanisms, showing that PIN1 functions as an auxin uniporter, whereas AUX1 acts as an auxin and proton symporter. Together, these findings advance our understanding of the molecular basis of PAT in plants, and provide a foundation for future agricultural applications targeting auxin transporters.

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.