Mingmei Wu

Starting from a high-efficiency monochromatic phosphor, site engineering together with lattice-distortion-generated luminescent centers unlocks full-visible-spectrum emission in single-phase Li ₄ CaSr(SiO ₄ ) ₂ , delivering a record EQE of 46.0%.

Mechanoluminescence (ML) materials, capable of converting mechanical action into light emissions, hold great promise for stress‐sensing applications. However, the lack of general design principles for developing efficient and self‐powered ML materials has significantly impeded progress in this field. Herein, we report a novel class of self‐powered Sr ₃ P ₄ O ₁₃ (SPO) ML materials enabled by energy transfer from electron‐hole pair recombination induced by contact electrification. Through combined analyses using piezoresponse force microscopy (PFM), thermoluminescence (TL) spectroscopy, triboelectric potential measurements, temperature‐dependent ML spectra, and density functional theory (DFT) calculations of charge density difference, the underlying ML mechanism is elucidated as contact electrification‐induced energy transfer. Systematic investigation of SPO:Bi and a series of SPO:RE (RE = Eu, Tb, Dy, Sm, Er, Tm) phosphors reveals that activator ions possessing spin‐allowed broadband absorption are favorable for achieving efficient ML, a correlation that extends consistently to radioluminescence (RL) and cathodoluminescence (CL) behaviors. Leveraging the favorable luminescence performance, we demonstrate proof‐of‐concept applications in a single material platform that integrates handwritten signature authentication, structural health monitoring, X‐ray imaging, optical temperature sensing, and multi‐stimulus information encryption. This work provides fundamental insights into contact electrification‐induced ML and establishes important design guidelines for developing efficient ML materials and their versatile applications.

The advancement of near‐infrared phosphor‐converted light‐emitting diodes (NIR pc‐LEDs) for next‐generation optoelectronic applications is critically dependent on the availability of high‐performance phosphors. In this study, a series of NIR‐emitting phosphors with high luminescence efficiency and excellent stability was developed by co‐doping Cr ³⁺ , Yb ³⁺ into the Mg ₂ SiO ₄ (MSO) host. Efficient energy transfer from Cr ³⁺ to Yb ³⁺ was achieved in the MSO: Cr ³⁺ , 2.5%Yb ³⁺ phosphor, reaching an energy transfer efficiency of 91.82%, as determined from the luminescence intensity measurement. The optimal MSO: Cr ³⁺ , 1.5%Yb ³⁺ phosphor exhibits a remarkable internal quantum efficiency (IQE) of 71.8% and an external quantum efficiency (EQE) of 48.8%. It also demonstrates remarkable thermal stability, retaining 71.5% of its initial intensity at 423 K. Additionally, the material shows exceptional humidity resistance, retaining approximately 98.05% of its initial intensity after 7 days of exposure to harsh conditions (85°C and 85% relative humidity, RH). Notably, no significant chromaticity shift is observed at elevated temperatures, indicating excellent color stability. Finally, an NIR pc‐LED was fabricated by combining the optimized phosphor with a 450 nm commercial blue LED chip. The device delivers a high output power of 718.67 mW with an electro‐optical conversion efficiency of 12.53% at a driving current of 600 mA. Collectively, these results underscore the promising potential of this phosphor for applications in optical bioimaging and night vision.

The commercialization of green hydrogen production through organic photocatalyst‐promoted solar water splitting for hydrogen evolution is limited by inefficient charge separation and sluggish interfacial kinetics. Herein, this problem is addressed using an ice template–assisted photochemical reduction strategy that integrates molecular‐level interfacial contact between a trefoil‐shaped donor–acceptor molecule (DTAB) and ultrathin carbon nitride nanosheets (UCNS) with Cu single atoms (SAs) anchoring and Pt nanodots (NDs) deposition. The intimate interface in the resulting DTAB–UCNS/CuPt photocatalyst generates a built‐in electric field promoting the separation of photogenerated carriers. The DTAB harvests visible light and injects electrons into UCNS, with these electrons subsequently funneled to Pt NDs via Cu SAs. The electronic coupling between Cu SAs and Pt NDs affects the position of the Pt d ‐band, thus optimizing the H* adsorption/desorption equilibrium and enhancing surface reaction kinetics. The hydrogen evolution rate of DTAB–UCNS/CuPt (261.16 mmol g ⁻¹ h ⁻¹ ) is 248.7 times higher than that of UCNS/Pt (1.05 mmol g ⁻¹ h ⁻¹ ) and ranks among the highest reported for carbon nitride–based photocatalysts under comparable conditions, highlighting the strong potential of our strategy to advance photocatalytic hydrogen evolution toward practical green hydrogen production.

Broadband near-infrared (NIR) light sources that combine high power, high efficiency, and wide spectral coverage are essential for emerging applications in imaging, sensing, and illumination. Phosphor-converted light-emitting diodes (pc-LEDs) offer a scalable platform for such sources, but their performance is often limited by weak visible-light absorption of d -electron emitters originating from parity-forbidden transitions. Here we report a symmetry engineering strategy that overcomes this limitation by partially relaxing the parity selection rules in Cr ³⁺ -activated systems. Controlled lattice perturbations in a rigid silicate framework break the local symmetry of Cr ³⁺ -coordinating octahedra, significantly enhancing blue-light absorption without increasing dopant concentration. In parallel, crystallographically distinct sites enable efficient inter-site energy funneling, directing excitation toward energetically favourable emission centers and improving radiative efficiency. The optimized phosphor exhibits broadband NIR emission at λ _max ~ 880 nm with an internal and external quantum efficiency of 93% and 64%, among the highest reported values and along with excellent thermal and environmental stability. When integrated with a blue InGaN chip, the phosphor-converted device enables watt-level NIR output with excellent operational stability. These results highlight the role of local structural control in improving the performance of d-electron emitters and provide a viable route towards efficient broadband NIR light sources.

A comprehensive review on Cr ³⁺ -doped near-infrared phosphors focusing on preparation, luminescence, and LED applications.

Integrating the dual capabilities of X‐ray detection/imaging and radiation thermometry into a single scintillator through rational materials design opens a new avenue toward advanced multi‐functional radiation‐sensing applications. However, developing the functional material remains a challenge. Here, we report a multifunctional X‐ray induced persistent luminescence (PersL) SrZnP ₂ O ₇ (SZPO):Dy,Tb phosphor for multimodal sensing applications, including stress monitoring, X‐ray detection/imaging, and radiation thermometry. Upon ultraviolet (UV) light and X‐ray excitation, an efficient energy transfer (ET) from Dy ³⁺ to Tb ³⁺ occurs via an electric dipole–dipole interaction mechanism. The phosphor also exhibits pronounced mechanoluminescence (ML), that enables real‐time structural health monitoring and visual stress distribution mapping in building structures such as bridges. Furthermore, flexible films fabricated with SZPO:Dy,Tb demonstrate excellent recoverable PersL and radioluminescence (RL) with retained anti‐thermal quenching (ATQ) behavior, facilitating delayed X‐ray imaging and reliable high‐temperature detection. By exploiting the distinct temperature‐dependent RL responses of the Dy ³⁺ and Tb ³⁺ emissions, we achieve high‐performance radiation‐excited optical thermometry with superior sensing performance. This work not only presents an integrated phosphor platform for multi‐scenario radiation sensing but also provides a viable design paradigm for developing advanced functional materials in X‐ray technology and thermometric applications.

Although polymeric carbon nitride holds promise for solar-driven hydrogen production, its scalability is constrained by reliance on costly vacuum conditions and scarce freshwater supplies. Herein, ultrathin carbon nitride nanosheets are covalently linked to electron-donating pyrene units via π-bridges. The resulting donor–π–acceptor frameworks, featuring a biphenyl π-bridge, exhibit reduced exciton binding energy and long-lived charge-separated states. In situ spectroscopic and electrochemical analyses collectively demonstrate efficient intramolecular electron transfer and a strengthened built-in internal electric field. Theoretical calculations suggest that electron accumulation on heptazine units may enhance the adsorption of Na⁺/Mg²⁺–triethanolamine complexes, accelerating hole consumption in seawater. As a result, the optimal donor–π–acceptor catalyst shows efficient photocatalytic seawater splitting under ambient pressure and natural sunlight, achieving a hydrogen evolution rate of 134 mmol h⁻¹ g⁻¹. Here, we show a molecular design strategy that advances photocatalytic ambient-pressure seawater splitting and promotes the commercialization of green hydrogen production.