Jianbo Wang

Perovskite light-emitting diodes (PeLEDs) have recently demonstrated substantial potential for next-generation micro-displays due to their excellent efficiency and brightness. However, the best-performing PeLEDs typically suffer from low brightness and severe efficiency roll-off, as well as the considerable challenge of monolithic integration at pixel sizes down to 2 μm. Here, we present a lattice-engineering approach for thermally evaporated perovskites that simultaneously achieves high-performance PeLEDs and high-definition monolithic integration for perovskite micro-display applications. The lattice engineering achieved by in situ incorporation of FABr effectively suppresses Ruddlesden–Popper (RP) faults within nanocrystals and yields a uniform electric-field distribution, thereby reducing charge accumulation and suppressing Auger recombination. We further fabricated PeLEDs with a fully vacuum-deposited device architecture, demonstrating an external quantum efficiency (EQE) of 20.6% and high brightness levels exceeding 160,000 cd m ⁻² , with reduced efficiency roll-off. More importantly, through process and device optimizations, we achieved nanometer-scale conformal deposition on the surfaces of complementary metal-oxide-semiconductor (CMOS) driver pixel pits, thereby developing a perovskite micro-display with a resolution of 3,000 pixels per inch (PPI) capable of displaying vivid video. Our research paves the way for advancing micro-display technology.

Thermally evaporated perovskite light-emitting diodes (PeLEDs) are attractive for scalable display manufacturing but remain limited by grain-boundary defects and residual strain. Here, we identify how a Lewis base passivator, PPF, reconstructs grain boundaries in evaporated CsPbBr₃ through coordination between P═O groups and undercoordinated Pb²⁺ sites. PPF relaxes grain-boundary tensile strain from 3.25 to 0.18% and reshapes the local projected electric field, leading to reduced defect-assisted nonradiative recombination and improved carrier injection. As a result, the PeLEDs deliver an external quantum efficiency of 17.6% and a T₅₀ of 66.7 min at an initial luminance of 1000 cd m⁻², compared with 8.8% and 16.2 min for control devices. These results establish a direct structure-field-performance correlation for vapor-deposited perovskites and provide guidance for evaporated perovskite optoelectronics.

Enhancing the ductility of refractory body-centered cubic (BCC) metals at the nanoscale remains a formidable challenge due to the intrinsically limited dislocation mobility, which often leads to premature brittle fracture. Here, we report the construction of a face-centered cubic (FCC)/BCC dual-phase structure in Mo nanowires (NWs) via non-equilibrium electron-stream excitation (electric current or electron-beam irradiation). Atomic-scale characterizations and first-principles calculations suggest that interstitial hydrogen can stabilize the FCC phase at the NW surface. Unexpectedly, the dual-phase NW shows a high uniform ductility of ~41.4% along the [011] direction, representing a nearly 300% enhancement compared to the single-phase BCC NWs. This extraordinary mechanical behavior originates from a two-fold deformation mechanism mediated by hydrogen: (1) During the initial plastic deformation, a discrete two-step FCC-to-BCC transformation proceeds via fractional dislocation slip, which effectively relieves local stress concentrations and thus inhibits surface crack initiation; (2) As deformation continues, we find that H can promote dislocation nucleation based on the analysis of surface energy and unstable stacking fault energy, thereby sustaining continuous plastic flow and delaying failure. The proposed strategy offers a pathway to overcome the inherent brittleness of nanosized Mo metals, opening up new opportunities for their application in advanced nano-electromechanical systems.

Unraveling the dynamic metal–support interactions of heterogeneous catalysts during the pretreatment environment is pivotal for modulating the phase structure and improving electrochemical activities. Here, we first investigate the hydrogen evolution reaction activity of Pt–SnO₂ catalysts treated under different temperatures. Subsequently, assisted by both experimental observations and density functional theory calculations, we provide atomic-scale insights into the reactive interaction between Pt nanoparticles and SnO₂ nanowires. The Pt nanoparticles gradually transform into Pt₃Sn, PtSn, and PtSn₂ intermetallic phases with increasing temperature, induced by the interlayer diffusion of Sn atoms. Finally, the catalytic activities of Pt–SnO₂ can be well-interpreted based on the nucleation of different intermetallic phases. Our results provide perspectives into the structure–property interplay in a metal/oxide heterogeneous catalyst, thus offering guidance for optimizing the catalytic performance.

Precise control of interfaces is crucial for spin generation, transport, and detection in opto-spintronics. However, the interface engineering for efficient spin injection remains a significant challenge. Here, we synthesized a helical structure of PbI₂ (R-PbI₂) via an interfacial chirality-induced growth approach at the heterostructure interface. This few-nanometer-thick R-PbI₂ layer shows a lower lattice mismatch with both the adjacent R-NEAPbI₃ (R-NEA refers to R-1-(1-naphtyl)ethylamine) and PbI₂ layers, and leads to an optimal chiral interface in the chiral heterostructure with minimized residual strain and defect density. Combined with circularly polarized pump-probe spectroscopic and spin-photovoltaic measurements, our chiral heterostructure interface contributes a spin-injection efficiency up to 68%, thus leading to a degree of polarization of 29% in photocurrent. The precise synthesis of a chiral interface offers a promising route to manipulate spin dynamics and achieve a high degree of spin polarization required for advanced opto-spintronic applications.

MXene, an emerging two-dimensional nanomaterial, has attracted considerable interest due to its large surface area, excellent mechanical strength, and superior electrical and chemical properties, making it a strong candidate for high-performance pressure sensors. However, its inherent tendency to self-stack limits the tunability of its interlayer structure, which is critical for resistance-based sensing mechanisms. In this work, we successfully achieved continuous tuning of MXene's interlayer spacing, effectively enhancing the sensitivity and overall performance of the pressure sensor. The optimized sensor exhibited outstanding linear sensitivities of 145.5 kPa^-1 in the low-pressure range (0-18 kPa) and 25.7 kPa^-1 in the medium range (18-50 kPa), along with fast response and recovery times of 68 and 40 ms. Furthermore, it demonstrated excellent durability with stable performance over 10,000 loading/unloading cycles. The sensor was further applied to real-time monitoring of human motions, health signals, and human-machine interactions, highlighting its strong potential in next-generation wearable electronics and smart sensing applications.

SnSe maintains a high figure of merit (ZT) at elevated temperatures, which is closely linked to its atomic structure. However, the nature of its high‐temperature (HT) phase remains controversial, primarily due to the lack of direct observations for thermal‐induced structural change. Here, the layer‐shuffling phase transition mechanism is characterized at the atomic scale by in situ transmission electron microscopy (TEM), assisted by theoretical calculations and machine learning. Notably, a slightly distorted HT α phase dominates at elevated temperatures, likely induced by the breakdown of long‐range coherence because of the dynamic disorder of Sn atoms. Further investigations into the electrical and thermal transport properties indicate that the HT α phase primarily contributes to the excellent thermoelectric performance of SnSe reported previously. This study provides a fundamental understanding of structure‐thermoelectric property correlations, paving the way for the development of advanced thermoelectric materials.