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Verified CAS / Academic Author27 Decoded Studies

Prof. GU Yan

School of Automation, Nanjing University of Science and Technology

Research Publications & English Decoded Briefs

Showing 27 publications
Acta Energiae Solaris Sinica2026DOI: 10.19912/j.0254-0096.tynxb.202608_9665

DC Bus Voltage Oscillation Analysis and Impedance Optimization Design for Two-Stage Power Conversion Systems

This paper addresses the prevalent design deficiency in two-stage power conversion systems (PCS), where single-stage converter stability is prioritized over cascaded coupling effects, leading to reduced system stability and DC bus voltage oscillations. By establishing bidirectional impedance models for the DC-side ports of both the front-end bidirectional DC/DC converter and the rear-end voltage source converter (VSC), the influence of power magnitude and direction on port impedance characteristics is systematically investigated. A novel impedance optimization control strategy based on capacitor current observation is proposed. This strategy reshapes the impedance models of both stages, reducing the resonant peak of the source converter's output impedance and mitigating the negative impedance characteristic of the load converter's input impedance, thereby preventing magnitude intersection of input and output impedances and expanding the stable operating range of the cascaded system. A state observer replaces high-precision current sensors for capacitor current measurement, reducing hardware cost. Simulation and experimental results validate the effectiveness of the proposed control strategy, demonstrating suppression of bus voltage oscillations under rated power conditions. The study reveals that stability margins differ between forward and reverse power flow: forward power flow induces negative input impedance in the VSC, causing instability, while reverse power flow yields positive output impedance, ensuring better stability margins. Future work will address transient stability under non-rated conditions such as continuous power fluctuations and weak grid with nonlinear loads.

Acta Energiae Solaris Sinica2026DOI: 10.19912/j.0254-0096.tynxb.202608_9659

Comprehensive Heat Transfer Performance of Deep Buried Pipe Systems for Medium-Deep Geothermal Energy Utilization

The utilization of medium-deep geothermal energy is primarily achieved through deep buried pipe closed-loop heat exchange systems, where the heat transfer efficiency is governed by the coupled effects of pipe depth, pump power, and heat pump energy consumption. Based on a casing-type deep buried pipe heat exchange project in Xi'an, three-dimensional full-scale numerical models with depths of 2039, 2539, 3039, and 3539 m were established to simulate heat extraction, pump power, and heat pump energy consumption over a 121-day operational period, thereby evaluating the comprehensive heat transfer performance. Results indicate that the comprehensive heat transfer power, accounting for pump power, increases approximately linearly with depth, with a maximum deviation of no more than 1.5% from the net heat transfer power. The pump pressure drop required to achieve a flow rate of 4.88 kg/s increases linearly with depth, reaching 622, 774, 924, and 1074 kPa for the four depths, respectively. The per-unit-depth pump power decreases with increasing depth, indicating that greater burial depth reduces the pump power proportion and enhances the overall heat transfer efficiency. The numerical model was validated against field experimental data, showing a maximum relative error of 4.26% in heat transfer power over a 72-hour period. These findings provide a quantitative basis for optimizing deep buried pipe system design and assessing the trade-offs between heat extraction and parasitic energy consumption in medium-deep geothermal applications.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4467-x

Ultra-flexible Transparent Self-powered Triboelectric Sensors for Eyelash-Guided Human-Machine Interaction

Conventional eye-movement interaction systems depend on video capture, infrared tracking, and image recognition, which impose inherent constraints on accuracy, response latency, and stability. This study introduces an eyelash-guided signal interaction system based on a triboelectric nanogenerator (PF-TENG) using PDMS-FDTS thin films. The system employs eyelash movements as interactive inputs, eliminating the need for complex optical acquisition devices. A CNN-LSTM hybrid neural network classifies distinct eyelash movement patterns with a classification accuracy exceeding 98.5%. The PF-TENG device exhibits ultra-flexibility and transparency, enabling seamless integration onto eyeglasses without obstructing the user's field of view. Experimental validation demonstrates real-time monitoring of ocular states for driving fatigue detection, accurately identifying fatigue signs and enhancing application potential in intelligent driving. The system offers a natural, comfortable input modality and significant advantages for human-machine interaction, with broad prospects in eye-movement control and intelligent transportation.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4502-1

Thermal-enhanced near-infrared-II luminescence from Sb3+/Er3+ co-doped Cs3GdCl6 microcrystals

Near-infrared-II (NIR-II, 1000-1700 nm) luminescent materials are pivotal for deep-tissue bioimaging and optical communication, yet their performance is often limited by low quantum yields and thermal quenching. Here, we report a thermal-enhanced NIR-II luminescence in Sb3+/Er3+ co-doped Cs3GdCl6 microcrystals synthesized via a modified Bridgman method. Under ultraviolet excitation, the co-doped microcrystals exhibit intense NIR-II emission centered at 1532 nm corresponding to Er3+: 4I13/2 → 4I15/2 transition, with a maximum relative sensitivity of 1.2% K−1 at 303 K. Notably, the integrated NIR-II emission intensity increases by 2.3-fold from 298 K to 373 K, demonstrating anomalous thermal enhancement. This behavior is attributed to the thermally activated energy transfer from Sb3+ sensitizers to Er3+ activators, as confirmed by temperature-dependent photoluminescence spectra and decay kinetics. The energy transfer efficiency reaches 86% at room temperature and further improves with rising temperature. The microcrystals also show excellent photostability, retaining 95% of initial intensity after 120 min continuous UV irradiation. Furthermore, we demonstrate a proof-of-concept wireless optical communication link using the microcrystals as a NIR-II phosphor, achieving a signal-to-noise ratio of 30 dB at 400 Hz modulation frequency. These findings provide a new strategy for designing thermal-enhanced NIR-II luminescent materials and expand their potential in temperature sensing and optical communication.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4244-0

Boosting the Operational Stability of Near-Infrared Perovskite LEDs Utilizing a Zinc Ion-Chelated Hybrid Electron-Transport Layer: The Critical Role of Interfacial Reactions

Near-infrared perovskite light-emitting diodes (NIR-PeLEDs) suffer from poor operational stability, largely due to interfacial reactions at the electron-transport layer (ETL)/perovskite interface. Here, we introduce a zinc ion (Zn2+)-chelated hybrid ETL derived from a Zn2+-chelated polyethylenimine ethoxylated (PEIE) complex, which partially retains the surface properties of ZnO but exhibits significantly reduced oxygen defects and surface-adsorbed hydroxyl groups. This well-modulated surface promotes perovskite crystallization and mitigates interface-induced deprotonation of organic cations during device operation. Consequently, NIR-PeLEDs employing this hybrid ETL achieve a peak external quantum efficiency (EQE) of 20.1%, a high radiance of 652 W sr-1 m-2, and an exceptional T50 lifetime of 270.7 hours at a high current density of 100 mA cm-2, which is over five times that of devices based on conventional ZnO nanocrystal (NC) ETLs. Our results present an effective ETL strategy for operationally stable NIR-PeLEDs and thoroughly reveal the critical role of regulating interfacial reactions in stabilizing buried interfacial contacts. These findings provide valuable insights for advancing perovskite optoelectronic devices that suffer from interface-induced performance degradation.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4201-0

Polysaccharide-Based Networks-engineered Orthopedic Implant for Synergistic Antimicrobial Defense and Osteogenic Regeneration to Potentiate PI3K-AKT/HIF-1-Mediated Open Fractures Treatment

Open fracture fixation faces dual critical challenges: bacterial infection and impaired bone healing. This study presents a rationally designed biomacromolecular network coating (Ti-GOED) on titanium alloy bone plates to simultaneously address these issues. The coating integrates antimicrobial and osteogenic components, achieving an optimal balance between antibacterial efficacy and biocompatibility. In vitro assays demonstrated that Ti-GOED eliminates over 99% of common pathogenic bacteria by inhibiting peptidoglycan synthesis, disrupting bacterial cell wall formation, compromising membrane integrity, and leading to intracellular DNA leakage and bacterial death. Concurrently, Ti-GOED enhances the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) via activation of the PI3K-Akt and HIF-1 signaling pathways. In vivo animal experiments confirmed strong antibacterial and osteogenic properties. This work provides a strategy for developing antibacterial coatings on medical devices, with significant potential for preventing and treating infections post-fracture fixation.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3610-7

Dual-confinement of reconstructed covalent organic framework for enhanced CO2 electrolysis in acid

Electrochemical CO2 reduction reaction (CO2RR) offers an attractive route to produce value-added multicarbon (C2+) products, yet suffers from competing hydrogen evolution and monocarbon production. Here, we propose a dual-confinement effect on CO2 reactant and *CO intermediate, induced by tuning the pore configuration of reconstructed covalent organic frameworks (RC-COFs). The highly crystalline microporous RC-COF-1, when coated on a Cu electrode, enhances local CO2 concentration and restricts CO diffusion, thereby promoting C-C coupling. In acidic electrolyte, the RC-COF-1@Cu electrode achieves a maximum C2+ Faradaic efficiency (FE) of 67.0% at 500 mA cm−2, while maintaining a total carbon product FE above 90% across a broad current density range (100–500 mA cm−2). Experimental and theoretical analyses confirm that the ordered micropores of RC-COF-1 modulate reactant adsorption and intermediate diffusion, leading to improved C2+ selectivity. This work underscores the critical role of COF pore architecture in microenvironment engineering for heterogeneous catalysis.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3748-9

Elimination of lattice strain to reconstruct ion transport channels facilitates direct regeneration of spent LiFePO4 cathode materials

Direct regeneration is a sustainable solution for recycling spent lithium-ion batteries (LIBs), yet the irregular strains induced by the irreversible FePO4 phase after cycling hinder Li+ replenishment in spent LiFePO4 cathodes. This study proposes a lattice stress modulation strategy that reduces FePO4 to Fe2P2O7, reducing unit cell volume from 271.7 to 122.6 Å3, releasing residual stress and reconstructing continuous Li+ transport channels. The phase transformation reconstructs FeO6 octahedra, lowering the migration energy barrier for ions. This synergistically weakens steric effects, facilitating Li+ replenishment and eliminating Li-Fe anti-site defects. Regenerated LiFePO4 cathodes achieve 80.2% capacity retention after 1000 cycles at 2C, outperforming commercial cathodes. The work establishes fundamental principles for the pre-treatment stage of direct regeneration and provides a paradigm-shifting solution for sustainable LIB recycling.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2025091203

Efficiency and mechanisms of tetracycline removal from water by enhanced peroxymonosulfate activation via carboxylated Fe2+

The persistence of tetracycline (TC) in aquatic environments poses significant ecological risks. This study developed a homogeneous reaction system based on carboxylated Fe2+ enhanced peroxymonosulfate (PMS) activation, using citric acid (CA) as a ligand. Carboxylation improved Fe2+ stability and catalytic activity, while solid PMS served as the oxidant, circumventing issues of traditional Fenton processes such as H2O2 instability, complex heterogeneous catalyst preparation, high disposal costs, and toxic metal leaching. The acidic pretreatment enabled by CA inhibited Fe2+ oxidation and promoted sustained PMS activation without external energy input. Under optimized conditions (TC 5 mg·L−1, Fe2+ 0.02 mmol·L−1, CA 0.001 mmol·L−1, PMS 2 mmol·L−1), 88.80% TC degradation was achieved within 60 min. Mechanistic studies revealed that CA protected Fe2+ active sites via carboxyl coordination, facilitating continuous generation of reactive species, including singlet oxygen (1O2) and sulfate radicals (SO4•−). 1O2 was the dominant species (50.5% contribution), followed by SO4•− (35.7%), synergistically driving efficient TC degradation while significantly reducing iron sludge production. Phytotoxicity assays confirmed that treated water exhibited no significant toxicity to wheat seedlings (P > 0.05), indicating effective ecological risk elimination. This work provides a low-energy, operationally simple, and environmentally friendly technology for antibiotic-contaminated water treatment, with promising practical application potential.

Journal of Environmental Engineering Technology2026DOI: 10.13205/j.hjgc.202604022

Synergistic Benefits of Pollution Reduction and Carbon Mitigation from Converting Food Waste into Carbon Sources for Wastewater Treatment Plants

The resource utilization of food waste contributes to reducing environmental pollution, driving nutrient cycling and biomass energy development, and promoting the resource recycling industry, achieving a win-win outcome for environment and economy. This study evaluated the resource recovery performance and environmental impacts of producing carbon sources for wastewater treatment through hydrolysis and acidification of food waste, comparing with two conventional alternatives: anaerobic fermentation and incineration. Results showed that among the three technologies, hydrolysis for carbon source production ranked middle in resource recycling efficiency, but its environmental benefits were superior to incineration and anaerobic fermentation. The hydrolysis process did not produce additional wastewater requiring treatment, and its greenhouse gas emissions and solid waste generation intensity were relatively low, at -40.7 kg CO2-eq/t and 9.3%, respectively. Carbon sources derived from food waste can replace commercial alternatives, reducing wastewater treatment costs and promoting synergies between pollution reduction and carbon mitigation. Sensitivity analysis revealed that water content in food waste significantly influences solid impurity generation and energy recovery efficiency of hydrolysis technology. In regions with high food waste generation and carbon source demand, hydrolysis technology is recommended to facilitate large-scale synergistic treatment of wastewater and food waste.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202508036

Optimization of Preparation Conditions for a Novel Composite Slow-Release Carbon Source and Its Denitrification Performance

To address the issues of insufficient carbon sources and low denitrification efficiency in rural domestic wastewater, this study developed and optimized a composite slow-release carbon source using corncob, rice husk, reed straw, polyvinyl alcohol (PVA), and sodium alginate (SA). The preparation conditions and raw material ratios were systematically optimized using Plackett-Burman (PB) design, response surface methodology (Box-Behnken design, BBD), and mixture-optimal design (MOD). The denitrification performance was evaluated through carbon release characteristics and denitrification experiments. The optimal preparation conditions were determined as PVA 8.64 g, SA 2.41 g, rice husk 3.82 g, corncob 4.47 g, reed straw 6.06 g, freezing time 19.11 h, and crosslinking time 12 h. The 7-day cumulative carbon release was (43.38 ± 1.3) mg·(g·h)−1. The release process followed first-order kinetics, Higuchi, Ritger-Peppas, and Weibull models, indicating that carbon release is controlled by multiple mechanisms including diffusion and skeleton erosion, ensuring stable slow-release characteristics. In denitrification experiments with influent NO3−-N concentration of 50 mg·L−1, the composite carbon source (RCR-PVA-SA) achieved a maximum NO3−-N removal rate of 90.8% after 10 days of operation, with a removal rate of 0.079 mg·(g·h)−1. Under dynamic conditions with hydraulic retention time (HRT) of 3 h, the average removal rate remained at 87.9%, demonstrating efficient and stable denitrification performance under both static and dynamic conditions. This research provides a reference for the preparation of natural slow-release carbon sources and the resource utilization of agricultural waste.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202508041

Stress Responses and Accumulation Characteristics of Duckweed (Landoltia punctata) to Lead Oxide Nanoparticles

Lead oxide nanoparticles (PbO NPs) are increasingly released into aquatic environments from industrial processes, posing ecological risks. Duckweed (Landoltia punctata) is a known lead hyperaccumulator, but its physiological and biochemical responses to PbO NPs remain unexplored. This study synthesized PbO NPs via a plant-mediated biosynthesis method and exposed L. punctata to concentrations of 0 (control), 10, 20, 30, and 40 mg·L−1 in hydroponic culture for 7 days. Results showed concentration-dependent effects: low concentrations (10–20 mg·L−1) stimulated growth, while high concentrations (≥30 mg·L−1) inhibited fresh weight, growth rate, and root length. Chlorophyll b content decreased significantly at ≥20 mg·L−1 (by 14.09%, 10.79%, and 18.48% at 20, 30, and 40 mg·L−1, respectively), while carotenoid content increased. Malondialdehyde content and activities of superoxide dismutase, peroxidase, and catalase increased with PbO NPs concentration, indicating oxidative stress. Lead accumulation reached 1265.65 mg·kg−1 at 30 mg·L−1 and 2030.01 mg·kg−1 at 40 mg·L−1, with bioconcentration factors >1 and lead removal rates above 68.94%. Subcellular distribution showed lead predominantly in the cell wall fraction, followed by soluble components and organelles. These findings demonstrate that L. punctata exhibits strong PbO NPs accumulation and stress tolerance, supporting its use in phytoremediation of metal nanoparticle-contaminated waters.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2025083003

Solar Interfacial Evaporation and Desalination Performance of Carbon Spheres-Corn Stalk Double-Layer Evaporator

To obtain freshwater from saline water and seawater, a double-layer evaporator consisting of carbon spheres and corn stalks was fabricated (abbreviated as CC). Corn stalks served as the evaporator substrate, and a mixed hydrogel of carbon spheres and polyvinyl alcohol functioned as the photothermal conversion layer. The solar-driven interfacial evaporation and desalination performance of the CC evaporator was investigated. The glucose-derived carbon spheres exhibited a uniform morphology and achieved 95% light absorption across 200–2500 nm. Under 1 sun (1 kW·m−2) irradiation, the CC with 3 cm height (CC-3) reached an exceptional evaporation rate of 3.55 kg·m−2·h−1 with a remarkable energy efficiency of 97.53%. When different wind speeds (1.5, 2, and 2.5 m·s−1) were applied, the evaporation rates further increased to 7.17, 8.92, and 10.41 kg·m−2·h−1, respectively. The evaporation rate of CC-3 for 3.5% saline was 3.46 kg·m−2·h−1. A 5-day long-time experiment exhibited stable desalination and excellent salt tolerance. Under a wind speed of 2.5 m·s−1, the evaporation rate reached 9.56 kg·m−2·h−1. In an outdoor natural light within a closed system and 2.5 m·s−1 of wind speed, the maximum evaporation rate and cumulative evaporation amount for seawater were 9.59 kg·m−2·h−1 and 66.0 kg·m−2, with no salt crystallization observed on the CC surface. These results demonstrate the potential practical application of the CC evaporator in seawater desalination.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3830-6

Helical wrapping and charge-transfer driven multi-stranded crystalline helices from a twisted figure-of-eight macrocycle

Controlled fabrication of artificial multiple-stranded helices is central to deciphering chirality complexity and hierarchical self-assembly processes. Inspired by biological helical nanostructures, we designed a twisted figure-of-eight chiral macrocycle (M1) from pyrene and benzene diimide subcomponents to direct hierarchical assembly of double- and quadruple-stranded superhelices. Single-crystal X-ray diffraction reveals that M1 undergoes charge-transfer and CH···π interactions-driven helical wrapping, forming right-handed (P) single strands that intertwine into quadruple π-helical superstructures. Crucially, the macrocycle's adaptive cavity and interstitial voids could bind electron-deficient naphthalene diimide (NDI) guests through charge transfer interactions, triggering transformation to left-handed (M) double helices. This structural shift induces helicity inversion and optical anisotropy changes, demonstrating a rare case of crystalline-state multiple-helix conversion with supramolecular chirality inversion. This work establishes a template-free methodology for synthesizing multiple-stranded π-helices and controlling their transformations through supramolecular engineering.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3833-1

Au@TiN Hybrid Nanostructures with Geometric, Compositional, and Optical Tunability

Developing plasmonic nanomaterials with compositions beyond noble metals is crucial for expanding their applications. Transition metal nitrides, such as titanium nitride (TiN), exhibit excellent plasmonic optical properties and photothermal conversion efficiency, showing promise in catalysis, photothermal therapy, and seawater desalination. However, the structure-property relationship governing their plasmonic optical properties remains unclear. Here, we constructed Au@TiN core-shell nanostructures and systematically investigated the tunability of their geometry, composition, and optical properties. By varying the Au core size and TiN shell thickness, we achieved precise control over the localized surface plasmon resonance (LSPR) from visible to near-infrared wavelengths. Single-particle scattering spectroscopy revealed distinct plasmon hybridization modes, with experimental spectra matching theoretical simulations. The Au@TiN nanostructures exhibited enhanced photothermal conversion efficiency (η = 78.5%) under 808 nm laser irradiation, significantly outperforming pure TiN nanoparticles (η = 45.2%). This work demonstrates multi-factor control over plasmonic effects in TiN, providing insights for designing TiN-based plasmonic nanomaterials for catalysis and sensing.

Journal of Environmental Engineering Technology2026DOI: 10.13205/j.hjgc.202606013

Comparative Analysis of CH4 and N2O Generation and Emission Characteristics in A2/O and A2/O-MBR Wastewater Treatment Plants

The A2/O-MBR process, owing to its superior effluent quality and smaller footprint, is increasingly adopted in newly built and upgraded wastewater treatment plants. However, systematic studies on its greenhouse gas (GHG) emissions remain scarce, and direct comparisons with the conventional A2/O process are lacking. In this study, two full-scale wastewater treatment plants employing the A2/O and A2/O-MBR processes under identical influent conditions, climate, and discharge standards were investigated. A high-frequency monitoring system covering the entire treatment train was established, and combined with measurements of dissolved CH4 and N2O, water quality parameters, and operational parameters, to elucidate the differences in GHG emission characteristics. Results showed that the daily average CH4 emission intensities were not significantly different between the two plants [(0.67 ± 0.22) and (0.65 ± 0.18) g/m3, respectively]. CH4 emissions mainly originated from sewer-derived anaerobic production and subsequent release in the pretreatment units (accounting for over 70% of the total emissions), with partial in-plant oxidation by methanotrophs. Temperature and aeration-induced stripping were identified as key driving factors, as CH4 emissions were positively correlated with ambient temperature and dissolved oxygen (DO). In contrast, more than 90% of N2O emissions occurred in the biological treatment units. The A2/O-MBR plant exhibited significantly higher daily N2O emission intensity [(0.132 ± 0.055) g/m3] than the A2/O plant [(0.060 ± 0.046) g/m3], largely due to intensive aeration and oxygen-enriched internal/external recirculation in the membrane tank, which enhanced N2O production and stripping. Correlation analysis further revealed that N2O emissions in the A2/O plant were positively related to influent COD and BOD5, indicating dominance of heterotrophic denitrification, whereas in the A2/O-MBR process they were mainly driven by NH3-N loading and DO, reflecting a nitrification-based pathway. Importantly, both processes exhibited CH4 and N2O emission factors that were significantly lower than the reference values recommended by the IPCC and industry guidelines, underscoring the necessity of localizing emission factors for accurate carbon accounting.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3892-2

Atomically dispersed Pt species anchored on Al3+-doped SrTiO3 for photocatalytic overall water splitting

Single-atom co-catalysts on semiconductor substrates offer a cost-efficient route to enhance photocatalytic performance with minimal precious metal loading. However, precise tuning of local coordination environments and construction of efficient single-atom co-catalysts remain challenging for overall water splitting. Here, we employ an icing-assisted photochemical reduction strategy to anchor atomically dispersed Pt species as hydrogen evolution co-catalysts on Al3+-doped SrTiO3 (Pt SA-STO). The optimized Pt SA-STO exhibits remarkable activity, with hydrogen and oxygen evolution rates of 13.62 and 6.71 mmol h−1 g−1, respectively, and a turnover frequency (TOF) of 2114.5 h−1. We pioneer the use of nuclear magnetic resonance (NMR) spectroscopy to quantitatively track the temporal evolution of Pt4+ to Pt2+ under continuous irradiation during the icing-assisted photoreduction. Advanced characterizations and theoretical calculations confirm that single-atom Pt co-catalysts facilitate directional transfer and extraction of photogenerated charge carriers, effectively suppressing surface recombination. This work provides insights into designing novel single-atom co-catalysts by deepening understanding of electronic configurations and active sites in photocatalytic overall water splitting.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3825-x

Correlating the dielectric properties with chain packing density of polar functionalities in hyperbranched polyimides

Polymer-based dielectric materials with high energy density and thermal stability are critical for modern electric/electronic industries. Polyimide (PI) based materials are promising due to their high temperature resistance and chemical inertness, yet their inherently low dielectric constant and limited charge-discharge energy density restrict applications in film capacitors. While incorporating ferroelectric or conductive fillers can enhance dielectric performance, batch-to-batch inconsistency and physical deterioration remain problematic. This study focuses on molecular structure design and modulation, preparing hyperbranched polyimides with different dianhydride monomers and branching degrees. The effects of chain packing density with polar groups on dielectric and energy storage performances were systematically investigated via experimentation and molecular simulation. Results demonstrate a significant correlation between monomers' electrical distribution and packing density in polymer systems. Molecular simulation further elucidated the underlying mechanism. This work establishes a foundation for designing polymer-based dielectric materials with high dielectric and energy storage performances at the molecular level.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2026012605

Effects of Four Synthetic Phenolic Antioxidants on Adipogenic Differentiation and Potential Mechanisms

Synthetic phenolic antioxidants (SPAs) are widely used, leading to environmental contamination and human exposure. However, studies on their effects on adipocyte differentiation and underlying mechanisms, particularly for emerging SPAs, are limited. This study evaluated the impacts of 4-tert-octylphenol (4-t-OP) and three novel antioxidants (AO 3114, AO 1135, AO 702) on adipogenesis using the mouse 3T3-L1 preadipocyte differentiation model. Lipid staining, triglyceride measurement, differentiation-related gene expression analysis, and transcriptomic approaches were employed. All four SPAs significantly promoted differentiation of 3T3-L1 cells into mature adipocytes and upregulated expression of peroxisome proliferator-activated receptor gamma (Pparγ) and mature adipocyte marker genes. Transcriptomic analysis revealed differential effects on gene transcription during early differentiation. GO and KEGG enrichment analyses indicated that these SPAs promoted adipogenesis by enhancing energy metabolism and protein synthesis, as well as regulating PPAR and other signaling pathways. In conclusion, the tested SPAs promote adipogenesis and disrupt lipid metabolism through distinct mechanisms, suggesting long-term exposure may cause metabolic disorder risks and pose a public health threat.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2026022702

Vertical Distribution and Emission Characteristics of Per- and Polyfluoroalkyl Substances in a Municipal Solid Waste Landfill

This study systematically investigated the occurrence and vertical distribution of per- and polyfluoroalkyl substances (PFAS) in solid waste, leachate, and surrounding groundwater at a municipal solid waste landfill in Fuyang City, Anhui Province, China. A total of 23 PFAS were detected in solid waste, with total concentrations (∑PFAS) ranging from 7.95 to 172.28 ng·g⁻¹. Trifluoroacetic acid (TFA), an ultrashort-chain PFAS, was ubiquitous, contributing on average 59% to the total PFAS mass. PFAS composition varied with depth: long-chain PFAS dominated in middle and upper layers, while short-chain and ultrashort-chain PFAS were more abundant in deeper layers, indicating enhanced downward migration of shorter-chain compounds. Sulfonic acid PFAS exhibited increasing relative abundance with depth. Leachate ∑PFAS concentration was 14.35 μg·L⁻¹, dominated by short-chain compounds such as PFPrS and PFBS, consistent with the composition in bottom-layer waste. Groundwater surrounding the landfill contained multiple PFAS, with concentrations decreasing with distance from the landfill, confirming the landfill as a source of PFAS to the surrounding environment. Multivariate analyses (PCoA and Bray–Curtis dissimilarity) revealed that some groundwater samples closely resembled leachate in PFAS composition, suggesting direct impact via leachate migration. These findings underscore the role of landfills as significant reservoirs and sources of PFAS, particularly ultrashort-chain compounds, and highlight the need for improved leachate management to mitigate groundwater contamination.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-4081-y

Multifunctional mitochondria-targeting energy disruptor for enhancing imaging-guided low-temperature photothermal therapy of melanoma

The evolution of precision medicine has propelled multimodal imaging-guided phototheranostics to the forefront for precise tumor diagnosis and therapy. Low-temperature photothermal therapy (PTT) offers a promising approach for the treatment of melanoma due to its non-invasiveness and minimal damage to normal tissues. However, its efficacy is limited by cancer cell thermal tolerance. To address this, a new type of multifunctional energy disruptor (CAMeO-Q NPs) is developed featuring homologous targeting and mitochondria targeting, and synergistically enhancing low-temperature PTT in melanoma by reversing heat shock protein 90 (Hsp90)-mediated thermal tolerance and blocking mitochondrial adenosine triphosphate (ATP) biosynthesis. The multifunctional energy disruptor enables precise trimodal imaging (fluorescence imaging/FLI, photoacoustic imaging/PAI, and photothermal imaging/PTI) guidance for low-temperature PTT. Comprising a mitochondria-targeting photothermal agent and an Hsp90 inhibitor, CAMeO-Q NPs induce selective mitochondrial damage under 660 nm laser irradiation and downregulate cellular HSP expression by ATP inhibition and Hsp90 inhibitor. This multifunctional energy disruptor provides a novel strategy for enhancing multimodal imaging-guided low-temperature photothermal therapy through combined homologous targeting, mitochondria-targeting, and Hsp90 inhibition.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4229-6

Upcycling spent LiFePO4 via a fluorine doping-assisted direct regeneration strategy for high-rate lithium-ion batteries

The escalating retirement of lithium-ion batteries (LIBs) necessitates efficient recycling technologies to recover cathode materials, particularly lithium iron phosphate (LFP), which dominates the traction battery market. Conventional pyrometallurgical and hydrometallurgical methods are energy-intensive and environmentally burdensome. Here, we report a fluorine doping-assisted direct regeneration strategy for spent LFP (SLFP) cathodes, yielding a regenerated LFP-F (RLFP-F) with a hybrid structure of ordered crystalline and disordered domains. Fluorine doping reduces the Li+ diffusion energy barrier, as evidenced by density functional theory calculations, and strengthens Fe–O bonding, suppressing Fe migration and anti-site defect formation. The O 2p band center shifts downward, increasing the Fe 3d–O 2p energy separation from 3.23 eV in pristine LFP to 3.46 eV in RLFP-F, enhancing structural stability and electronic conductivity. Electrochemical tests demonstrate that RLFP-F delivers a high-rate capability and excellent cycling stability. Life-cycle assessment reveals that direct regeneration consumes only 9.986 MJ kg−1 and emits 0.324 kg CO2-equivalent per kg of cell, significantly outperforming pyrometallurgy and hydrometallurgy. Economic analysis based on 2025 Chinese market prices indicates a net profit of $397.15 per ton of SLFP battery recycling, attributed to the closed-loop cathode-to-cathode design. This work provides a sustainable and economically viable route for upcycling spent LFP batteries.

SCIENCE CHINA Materials2025DOI: 10.1007/s40843-025-3366-9

Organic Solar Cells Surpassing 20% Power Conversion Efficiency: Material Innovations, Device Engineering, and Pathways to Flexible Power Suppliers

Organic solar cells (OSCs) have transitioned from <1% initial power conversion efficiency (PCE) to a benchmark exceeding 20% in single-junction and tandem architectures, marking a critical milestone for solution-processable photovoltaics. This review consolidates recent reports (2022–2025) on OSCs with PCE >20%, analyzing key strategies: photoactive material innovation (wide-bandgap polymer donors, narrow-bandgap non-fullerene acceptors), multi-component system construction, deposition protocol optimization, solid/solvent additive engineering, and hole/electron transport layer development. Empirical data from 15 high-impact studies reveal PCEs of 20.0–20.6% in single-junction devices and 20.2–26% in perovskite/organic tandem cells, with interfacial engineering (e.g., yttrium phosphotungstate, carbazole-modified 2PACz, naphthalene diimide interlayers) suppressing bimolecular recombination and enabling scalable large-area fabrication. Operational stability remains a bottleneck: amide-based cathode interlayers achieve 20% PCE with dual-modification mechanisms, while self-assembled monolayers enable hole transport layer-free devices with 18% efficiency and improved stability. The review identifies next-stage challenges: reducing voltage losses (to <0.5 V), scaling deposition uniformity beyond 100 cm², and achieving cost parity with silicon (<$0.30/Wp). These issues are critical for flexible and wearable power suppliers, where mechanical durability (<5% PCE degradation after 1000 bending cycles) and low-temperature processing (<150°C) are mandatory. The analysis provides a roadmap for industrial translation, emphasizing that material–device co-optimization, rather than isolated breakthroughs, will determine commercial viability.

SCIENCE CHINA Materials2025DOI: 10.1007/s40843-025-3331-0

Single-crystal SrTiO3 hollow sphere with ultrathin shell for efficient photocatalytic water splitting

Hollow nanostructures with highly accessible surfaces and short charge-transport distances are pivotal for photo(electro)chemical reactions. Perovskite-type SrTiO3 (STO) is a promising photocatalyst for solar water splitting, yet the synthesis of uniform hollow single crystals with well-defined shells remains challenging due to the cubic symmetry and thermodynamic instability of curved surfaces. Here, we report the controllable synthesis of single-crystal STO hollow spheres with ultrathin shells (UTSS-STO) via a simple etching method. Selective etching of low-crystallinity interiors within mesoporous STO single crystals (MS-STO) yields hollow spherical shells and 2D sheet-like single crystals. The resulting UTSS-STO exhibits a 2.5-fold enhancement in photocatalytic hydrogen evolution compared to MS-STO. This improvement is attributed to the ultrathin porous shell, which shortens charge transport lengths and provides abundant active sites, as well as interlayer stress and an optimized electronic band structure that facilitate charge separation. HAADF-STEM and EDS mapping confirm uniform distribution of Rh/Cr2O3 cocatalysts on both inner and outer surfaces of the shell. This work demonstrates the advantage of hollow spherical shells for STO photocatalysts and offers insights into the fabrication of uniform hollow single crystals for efficient solar energy conversion.

SCIENCE CHINA Materials2025DOI: 10.1007/s40843-025-3434-y

Confined Electrophoretic Deposition of Uniformly Dispersed Nanoparticle-Integrated Hydrogels with Enhanced Mechanical and Enzyme-Like Properties for Antibacterial Therapy

Nanoparticle-integrated hydrogels combine the favorable properties of hydrogels and nanoparticles, yet conventional integration methods fail to ensure uniform dispersion and full exposure of nanoparticles, resulting in suboptimal performance. This study introduces a confined electrophoretic deposition (EPD) strategy to fabricate hydrogels uniformly deposited with MnSiO3 nanoparticles (designated MnSiO3-based E-gels). The density of cross-linking points and electrostatic attraction at the cathode critically govern nanoparticle deposition behavior. The confined EPD strategy enables ultra-uniform deposition of positively charged nanoparticles (Ag, ZnO, NiO, Fe3O4, MoS2, MnO2, CuO, and ZIF-8) within hydrogel micropores in less than one minute. Nanoparticles deposited under the electrostatic field exhibit equidistant distribution, superior dispersity, and enhanced binding stability. Consequently, the E-gels demonstrate significant improvements in mechanical strength, adhesion, enzyme-like activity, and in vitro and in vivo antibacterial efficacy compared to conventional hydrogels. This confined EPD approach offers a versatile and efficient protocol for integrating polymer-based hydrogel networks with functional nanoparticles, holding promise for biomedicine and materials science.

SCIENCE CHINA Materials2025DOI: 10.1007/s40843-025-3550-4

Deuterated FAPbI3 Perovskite Films with Suppressed Deprotonation for Durable Solar Cells

Hybrid perovskite solar cells (PSCs) have reached a certified power conversion efficiency (PCE) of 27.0%, yet their operational lifetime remains constrained by the intrinsic instability of organic cations, particularly the deprotonation of formamidinium (FA). This study introduces a molecular deuteration strategy to stabilize FAPbI3 by substituting the active hydrogen in the N–H bond with deuterium. The reduced ground-state energy of the N–D bond induces a kinetic isotope effect, lowering the deprotonation rate constant from 5.15 × 10−8 to 2.42 × 10−8 s−1. Solar cells fabricated with deuterated FAPbI3 films achieve a PCE of 25.08% and retain 97% of their initial efficiency (T97) for 1264 h under continuous one-sun illumination at 55 °C. This approach addresses the fundamental deprotonation pathway that limits the longevity of FA-based perovskites, offering a viable route to intrinsically stable photovoltaic devices without relying solely on extrinsic barrier layers or passivators.

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.