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Verified CAS / Academic Author12 Decoded Studies

Prof. Weijun Wang

Harbin Institute of Technology (Shenzhen), Tsinghua Shenzhen International Graduate School, Tsinghua University

Co-Affiliations:School of Public Health, Qingdao UniversityBeijing Huanding Environmental Big Data Research Institute; Southern University of Science and TechnologyTsinghua UniversityCity University of Hong Kong

Research Publications & English Decoded Briefs

Showing 12 publications
SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4452-8

Efficient Ultranarrow-Band Red Eu³⁺ OLEDs Enabled by Modulated Energy Transfer and Charge Transport

Europium(III) complexes offer intrinsically narrow red emission (full-width at half-maximum < 5 nm) that is highly desirable for ultrahigh-definition displays, yet their electroluminescence performance is severely limited by unbalanced charge transport and inefficient energy transfer. This work reports a molecular design strategy that modulates both energy transfer and charge transport in Eu³⁺ OLEDs. The synthesized complex, Cz-Eu, incorporates a carbazole-functionalized ancillary ligand to facilitate host–guest energy transfer and hole transport. The single-crystal structure was deposited (CIF: Cz-Eu-cif.cif) and subjected to PLATON validation, which flagged 3 type-1 alerts (CIF construction/syntax errors), 8 type-2 alerts (possible structural model deficiencies), 12 type-3 alerts (low structure quality), and 4 type-4 alerts (improvement suggestions), with no duplication detected. These crystallographic alerts indicate that the reported structure requires further refinement before it can be considered reliable. Nevertheless, the device metrics demonstrate a promising route: the optimized OLED achieves efficient ultranarrow-band red emission, with the potential for high color purity and reduced power consumption. The findings underscore the critical role of ligand engineering in balancing charge fluxes and fostering efficient energy transfer, providing a viable pathway for next-generation red emitters. However, the structural ambiguities highlighted by the PLATON analysis warrant cautious interpretation of the structure–property relationships and suggest that additional crystallographic and device stability studies are necessary to substantiate the claimed performance.

New Carbon Materials2026DOI: 10.1016/S1872-5805(25)61036-5

Low-cost synthesis of large graphene oxide flakes by the total oxidation of large natural graphite flakes

Large graphene oxide (LGO) sheets offer significant advantages over smaller ones in various applications, yet their production via Hummers-type oxidation of large natural graphite flakes remains challenging due to difficulties in achieving full oxidation and avoiding fragmentation. This study provides the first direct evidence that large graphite flakes (up to 1 mm) can be completely oxidized without fragmentation under static conditions, as revealed by in-situ monitoring. The oxidation process is governed by diffusion of the oxidizer between layers, described by Fick's law, where a high oxidizer concentration gradient increases the diffusion rate. By minimizing the amount of concentrated H2SO4 solvent, we achieved a semi-solid state that elevates oxidizer concentration, facilitating Mn(VII) diffusion and enabling complete oxidation of gram-scale large flakes with significantly reduced reagent consumption. Reaction temperature was optimized to balance graphite oxidation and Mn(VII) self-decomposition. Using this approach, 200-, 100-, and 50-mesh natural graphite were fully oxidized with reduced H2SO4 and KMnO4 usage. After exfoliation, LGO with average lateral sizes of 27.3, 58.7, and 116.2 μm were obtained, respectively, with 100% conversion and yield over 165%. This work not only provides a scalable, cost-effective strategy for LGO production but also advances the fundamental understanding of Hummers-type oxidation.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2025010203

Release Characteristics of Organic Pollutants and Occupational Exposure During Lithium Battery Production and Disposal: A Case Study on N-Methylpyrrolidone

The production and disposal of lithium batteries release not only hazardous metals and particulates but also substantial amounts of harmful organic pollutants. This study focuses on N-methyl-2-pyrrolidone (NMP) to investigate the environmental release and human exposure of organic pollutants throughout the lithium battery lifecycle. Using liquid chromatography-high-resolution mass spectrometry (LC-HRMS), NMP was quantified in environmental samples from battery production and dismantling facilities, as well as in pyrolysis products from simulated thermal recovery of mainstream lithium batteries. Key release stages were identified: slurry mixing and coating/drying during production; shredding, electrolyte volatilization, and high-temperature pyrolysis during disposal. In unprotected occupational settings, estimated NMP exposure via dust ingestion exceeded reference doses, underscoring the need for health impact assessments and evaluation of protective measures. This research provides critical insights into the environmental release and population exposure of organic pollutants across the lithium battery lifecycle, informing health policy for vulnerable populations.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3876-5

Ultrathin and flexible electromagnetic interference shielding films by interface-confinement strategy

Electromagnetic interference (EMI) shielding technology is evolving from traditional bulky metal enclosures toward ultrathin, conformable, and flexible films. However, as the thickness of the shielding layer decreases, the electromagnetic wave absorption efficiency significantly deteriorates, leading to a marked decline in overall shielding performance. To overcome this intrinsic 'thickness–performance dilemma', porous structural designs are often employed to enhance multiple internal reflections and absorption. Nevertheless, such strategies typically suffer from uncontrollable thickness, poor spatial uniformity, and low process compatibility. To address these challenges, a joint team from the Gwangju Institute of Science and Technology and Seoul National University proposed an embedded MXene-in-metal (EXIM) shielding strategy. By embedding a non-porous MXene layer within a metallic film, a metal–MXene–metal heterolamellar architecture was constructed. Remarkably, this ultrathin structure achieves an EMI shielding effectiveness of ~70 dB at only ~1 μm thickness (up to 80 dB at 1.9 μm), breaking the conventional trade-off between reduced thickness and performance degradation. The superior performance originates from the conductivity contrast between the metal and MXene layers, which forms electromagnetic confinement wells. The localized electromagnetic waves undergo multiple polarization losses induced by interfacial dipoles, resulting in efficient energy absorption at thin thicknesses. The study further reveals that the EMI shielding performance of EXIM films primarily depends on the number of metal–MXene heterointerfaces rather than the total thickness. Multilayer stacking (e.g., Cu/Ti3C2Tx/Cu) notably enhances absorption efficiency while imparting excellent isotropy and flexibility. Moreover, introducing a Cr–Al dual-metal passivation layer effectively suppresses MXene oxidation, ensuring long-term operational reliability. The EXIM films are compatible with conventional fabrication and packaging techniques, including physical vapor deposition and spray coating, enabling scalable and large-area production. Practical demonstrations in USB 3.0 chips and flexible Schottky diodes confirm their outstanding capability in mitigating Bluetooth interference and blocking electromagnetic noise. This work is pioneering in that it introduces a new shielding mechanism based on conductivity contrast-induced electromagnetic confinement, achieves ultrahigh shielding effectiveness and mechanical flexibility within an ultrathin (<2 μm) structure, and elucidates a dipole-dominated interfacial polarization loss mechanism that provides theoretical insights into the design of 2D-material-based heterostructured shielding systems. Moreover, it opens up a new path for EMI shielding to shift from 'thick structure reflection' to 'heterogeneous interface confined absorption', providing a novel solution for realizing free-form, interference-free intelligent electronic packaging.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202509020

Effect of Three-Stage Reflux Ratio on the Performance of AAOA-MBR Process for Municipal Wastewater Treatment

The AAOA-MBR (anaerobic-anoxic-oxic-anoxic membrane bioreactor) process is widely used in municipal wastewater treatment, but its multi-stage internal recirculation complicates sludge retention time (SRT) and carbon source distribution. This study systematically regulated three reflux ratios (R1: membrane tank to oxic tank; R2: oxic tank to anoxic I tank; R3: anoxic II tank to anaerobic tank) in a pilot-scale system (0.24 m3·d−1) to reveal their effects on nutrient removal and membrane fouling. When R1:R2:R3 = 300%:200%:100%, effluent COD, TN, TP, and NH3-N met discharge standards. Reducing R1 and R2, thereby decreasing total reflux ratio from R=6 to R=3, shortened SRT, which suppressed nitrifier accumulation and increased effluent COD and TN, but decreased TP. High-throughput sequencing of anoxic I and oxic tanks showed that denitrifying bacteria (Thauera and Ottowia) relative abundances decreased from 0.68% to 0.42% and 0.51% to 0.24%, respectively, while the phosphorus-accumulating organism Candidatus_Accumulibacter increased from 0.78% to 1.12%, enhancing phosphorus removal. Additionally, lowering R1 to 200% caused sludge accumulation in the membrane tank, exacerbating membrane fouling. Thus, internal recirculation ratios must be adjusted based on influent characteristics to balance nutrient removal and membrane performance.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202510041

Ten-Thousand-Ton Scale Engineering Practice of Retrofitting a UASB Reactor into an Aerobic Granular Sludge Process

This study presents a full-scale engineering practice of retrofitting an idle upflow anaerobic sludge blanket (UASB) reactor into an aerobic granular sludge (AGS) system for treating low-strength municipal wastewater. The design capacity was 20,000 m3/d (maximum 24,000 m3/d), achieving separate treatment of industrial and domestic wastewater to reduce operational costs. Systematic analysis covered hydraulic capacity enhancement, effluent quality, pollutant removal efficiencies, sludge granulation progress, and operational costs. Results showed rapid start-up: the system reached 75% of design capacity by day 10 and 90% by day 26. During a 4-month operation, average removal efficiencies for COD, NH4+-N, TN, and SS were 83.2%, 97.0%, 75.9%, and 94.4%, respectively, even under low influent BOD5/TN ratios (typically below 4). Granulation progressed quickly: by day 44, average particle size was 2.6 times that of the inoculum and over 4 times that of flocs, with granules (>200 μm) accounting for 17.3%; by day 110, these values increased to 3.2 times and 5 times, with granule proportion reaching 33.4%. Compared to the previous year (June–August), the AGS process reduced electricity consumption, chemical consumption, and sludge production by 77.3%, 25.4%, and 30.4%, respectively, while saving 65.6% of footprint. This ten-thousand-ton case provides a practical basis for AGS technology application in China.

Journal of Environmental Engineering Technology2026DOI: 10.13205/j.hjgc.202607006

Global Warming Potential Analysis of Air Pollution Control Processes in Municipal Solid Waste Incineration under Ultra-Low Emission Standards

This study evaluates the global warming potential (GWP) of three typical air pollution control device (APCD) configurations in municipal solid waste (MSW) incineration under ultra-low emission standards. The configurations are APCD1 (SNCR+SDS+DS+ACI+FF), APCD2 (SNCR+SDS+DS+ACI+FF+SCR+WS), and APCD3 (SNCR+SDS+DS+ACI+FF+WS+SCR). Life cycle assessment (LCA) was applied to quantify GWP. Results indicate that APCD3 exhibits the highest GWP due to increased electricity consumption, yet it achieves the lowest pollutant emissions among the three. APCD1 shows the highest NOx emissions, contributing significantly to GWP, and requires technological upgrades. APCD2 consumes more resources but does not proportionally reduce emissions, suggesting inefficiencies. Electricity consumption is the dominant factor influencing GWP across all processes; reducing electricity use and improving energy efficiency are critical for mitigating environmental impact. The study recommends further research on CO2 reduction strategies and adoption of more efficient DeNOx technologies to align MSW incineration with ultra-low emission and low-carbon goals.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3903-4

Near-Perfect Light-Capture Materials with High Environmental Stability

Cross-wavelength near-perfect light capture technology is crucial in various fields, including spectroscopy, energy conversion, and electromagnetic control. Nevertheless, the primary challenge in broadband absorption is effectively coordinating the intrinsic response behavior of various electromagnetic waves across the nanometer-centimeter scale when interacting with matter. By adopting a multi-scale structural design strategy, the carbon-zirconium heterointerface is integrated into the macroscopic periodic unit cell (PUC) to develop an ultra-wideband light capture material. The optical coupling effect, strengthened by electronic transitions, molecular motion, and spatial scattering effects, endows ZC-PUC with exceptional light-capture performance ranging from ultraviolet to microwave frequencies. Specifically, the ZC-PUC absorber possesses a near-perfect absorption rate of 95.7% across the ultraviolet-visible-infrared spectrum (190–2500 nm), and an effective absorption coverage of 99.99% in the microwave and terahertz bands (1997.9 GHz). More importantly, the as-prepared material maintains the morphology structure and physical phase even when exposed to an alkaline or acidic environment for 365 days and simultaneously possesses stable light capture properties. The easily scalable approach retains excellent structural stability and ultra-wideband light trapping capability under extreme conditions, offering a versatile platform for the development of next-generation devices.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3977-8

Solvent-Hydrolysis-Driven Engineering of Ordered Single Quantum Well 2D Perovskites

Single quantum well (single-QW) two-dimensional (2D) perovskites are poised to revolutionize optoelectronic devices owing to their superior stability and optoelectronic properties. However, solution-processed 2D perovskites typically suffer from disordered multiple-QW structures, leading to inconsistent device performance. Here, we introduce a solvent-hydrolysis-driven method to control crystallization kinetics, yielding highly ordered single-QW 2D perovskite films. Dimethylamine (DMA), generated from the hydrolysis of N,N-dimethylformamide (DMF), serves as a critical mediator, preventing cluster aggregation and ensuring a uniform colloidal distribution. This approach circumvents the formation of a heterogeneous intermediate phase, thereby promoting the formation of a homogeneous (DMA,MA)PbI3 phase, which is essential for single-QW film development. The resultant photodetector exhibits outstanding performance, with a responsivity of 1153 mA/W and a detectivity of 6.98 × 10^12 Jones, along with excellent photostability under ambient conditions. These attributes render it ideal for photoelectric imaging sensors and large-scale integration. Our findings establish a scalable, solution-processed strategy for high-performance 2D perovskite materials, opening new avenues for advanced optoelectronic applications.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-4032-x

Achieving 19.41% Efficiency in Thickness-Insensitive All-Polymer Solar Cells via Interface Modifier-Mediated Morphological Modulation

This study introduces a dual-compatibility third component as an interfacial modifier to precisely regulate the active layer morphology of bulk heterojunction organic solar cells (BHJ-OSCs). This approach successfully suppresses excessive phase separation, significantly enhancing the performance of thick-film devices. The interface-styling strategy enhances donor–acceptor interactions, optimizes vertical phase separation morphology, extends exciton diffusion length, improves exciton dissociation efficiency, facilitates efficient charge transport, and effectively suppresses trap-assisted recombination. The ternary device based on PM6:PCN3:PY-IT achieved a power conversion efficiency (PCE) of 19.41%, which was much higher than that of the PM6:PY-IT binary system (18.67%). The device maintains excellent performance at an active layer thickness of 200 nm, achieving a high PCE of 18.25%. This study demonstrates the significance of using dually compatible molecules for interface modification in all-polymer solar cells (all-PSCs), providing theoretical guidance for the fabrication of high-performance thick-film devices.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-4047-0

Facile Construction of VS2@GNSs Composites with 1D/2D Hierarchical Structures for Efficient Electromagnetic Wave Absorption

The proliferation of electronic devices has exacerbated electromagnetic pollution, necessitating advanced electromagnetic wave (EMW) absorbing materials. In this study, VS2 nanorods were uniformly grafted onto graphene nanosheets (GNSs) via a facile ball milling method, constructing 1D/2D hierarchical VS2@GNSs composites with superior EMW absorption properties. The minimal reflection loss (RLmin) reached -49.83 dB at a thickness of 1.83 mm, while an ultra-broad effective absorption bandwidth (EAB) of 6.72 GHz was achieved at 1.96 mm. These performances are attributed to enhanced impedance matching and EMW attenuation capacities. Computer simulation technology (CST) full-wave simulations confirmed remarkable radar cross-section (RCS) suppression, with a reduction value of up to 20.38 dB m2 compared to a metallic substrate. This work provides theoretical and experimental guidance for designing high-performance stealth materials.

SCIENCE CHINA Materials2025DOI: 10.1007/s40843-025-3535-8

Efficient Orbit-Torque Driven Spiking Neuromorphic Device Mimicking the Selective Attention Mechanism for Self-Adaptive Recognition

The brain's selective visual attention mechanism (SVAM) enables robust visual recognition in noisy environments through diverse neural action potential peaks acting as filters. Spiking neural networks (SNNs) mimic this paradigm but limited noise immunity and high write current density hinder brain-like efficiency. Hardware implementing SVAM necessitates spiking spintronic devices with noise-resistant and low operation current densities; such devices remain unreported. Here, we report an orbit-torque (OT) actuated ferromagnetic spiking synapse and neuron featuring a tunable peak action potential. These are more akin to biological neurons with varying sensitivities to external sensory stimuli, thereby augmenting the perception aptitude of the system in complex surroundings. Capitalizing on the high-efficiency OT, the ferromagnetic device demands a write current density of 5 × 10^6 A/cm^2, which is an order of magnitude lower than other spiking devices actuated by spin-orbit torque. Leveraging these neuromorphic devices, an all-spin SNN with low current density and tunable action potential peak has been fabricated, successfully mimicking the SVAM. In complex noise environment, the SNN achieves 92% on Cifar-10 and 95% on MNIST dataset, surpassing state-of-the-art spin-based SNNs by 5%. Our work provides a promising avenue for exploring the SVAM-inspired spiking neuromorphic devices, enhancing the bionic performance of the SNNs.