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Verified CAS / Academic Author10 Decoded Studies

Prof. Nan He

Qilu University of Technology (Shandong Academy of Sciences)

Research Publications & English Decoded Briefs

Showing 10 publications
SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4412-y

Local van der Waals gaps and resonant levels enhance thermoelectric performance of lead-free GeTe

GeTe-based thermoelectric materials are promising lead-free alternatives to PbTe, but their intrinsically high Ge vacancy concentration (~10^21 cm^-3) leads to excessive carrier density and degraded Seebeck coefficient. This study integrates resonant levels (RLs) via In doping and local van der Waals gaps via Sb/Bi alloying to decouple electron and phonon transport. The optimal composition Ge0.91Sb0.04Bi0.04In0.01Te exhibits a Seebeck coefficient of ~287.31 μV K^-1 at 323 K, more than double that of the In-free sample (~102.28 μV K^-1). The peak figure of merit zT reaches ~1.8 at 723 K, with an average zT of ~1.0 over 323–723 K. Vickers hardness is enhanced to ~224 HV, a ~93% improvement over pristine GeTe (~116 HV). X-ray diffraction reveals a structural evolution toward a pseudo-cubic phase with increasing In content, and the (202) peak shifts to lower angles, indicating lattice expansion. These results demonstrate that synergistic RLs and van der Waals gaps effectively optimize carrier concentration and suppress thermal conductivity, offering a viable route for high-performance, mechanically robust GeTe thermoelectrics.

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/s40843-025-3658-1

Facile Synthesis of Efficient Blue-Light-Emitting Copper(I) Halide Hybrid Phosphors for Applications in pc-WLEDs and X-ray Imaging

Organic-inorganic hybrid copper(I) halide semiconductors have attracted extensive attention for applications in phosphor-converted white light-emitting diodes (pc-WLEDs), X-ray imaging, and photodetectors because of their superior photo/radioluminescence, structural diversity, and eco-friendliness. In previous work, a strategy combining coordinated anionic inorganic modules with cationic derivatives yielded highly efficient blue-emitting hybrids, but synthesis complexity limited practical use. Here, we report a facile, efficient, and rapid solution-based ultrasonic treatment method for synthesizing high-performance blue-emitting phosphors using inexpensive, commercially available tetraethylammonium halides (TEAX, X = Cl, Br, I). The synergistic interplay of ionic and covalent bonds in these compounds endows them with a high photoluminescence quantum yield (PLQY) of 70% and excellent stability. These materials exhibit thermally activated delayed fluorescence (TADF), delivering outstanding performance in pc-WLEDs and X-ray imaging. Their exceptional properties highlight significant potential for use in optoelectronic devices and X-ray scintillators. This work provides an important reference for rapid synthesis of high-performance copper(I) halide hybrid phosphors and paves the way for commercial application.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202507043

Thermal Steel Ball-Enhanced Rotary Drum Drying of Sludge: Drying Characteristics, Moisture Diffusion Behavior, and Mechanisms

Municipal sludge with high moisture content and strong viscosity tends to form a dense crust during conventional rotary drum drying, reducing heat and mass transfer efficiency and prolonging drying time. This study proposes a thermal steel ball-enhanced rotary drum drying method that introduces high heat capacity, high thermal conductivity steel balls to achieve synergistic contact heat conduction and mechanical disturbance. An evaluation system incorporating dimensionless moisture ratio (MR), drying rate (DR), characteristic drying time (tdry), effective moisture diffusivity (Deff), and volumetric evaporation intensity (U) was established. Results show that compared with conventional drying, steel ball-enhanced drying increased maximum drying rate (DRmax) by 22.59%–41.19%, U by 38.06%–93.43%, and shortened tdry by 27.56%–48.30%, with more pronounced advantages under high load conditions. Deff was significantly higher throughout the process, with maximum increase up to 48.30%, indicating that ball rolling and collision effectively disrupt the crust and promote moisture migration. Mechanistic analysis reveals that the performance enhancement arises from the dual action of thermal-mechanical coupling and mechanical disturbance, which enhances local heat flux via contact conduction and dynamically renews the drying interface, shortening diffusion paths. This study elucidates the heat and mass transfer mechanisms of thermal steel ball-enhanced sludge drying, providing theoretical support and technical reference for efficient sludge volume reduction and dryer design optimization.

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.

Journal of Environmental Engineering Technology2026DOI: 10.13205/j.hjgc.202605004

Systematic Governance Framework for Quality and Efficiency Improvement of Sewage Pipeline Networks in Rainy Cities of Southern China

To address the decline in operational performance of sewage pipeline networks in rainy cities of southern China caused by structural defects, stormwater-sewage cross-connections, and external water intrusion, a systematic governance framework comprising precise investigation, dynamic regulation, graded rehabilitation, and smart operation and maintenance was established. A zoned priority evaluation model was developed with comprehensive problem severity (P) and governance contribution (B) as core indicators, based on which differentiated governance strategies were formulated. Supported by a digital platform, monitoring, assessment, rectification, and verification data were integrated to develop a digital twin system for the pipeline network, and a correlation-based analysis and closed-loop operation and maintenance mechanism linking rainfall, groundwater level, and network hydraulic load was established. A typical urban area in Jiangxi Province was selected as the case study. After implementation, the mean COD concentration of terminal sewage in the study area increased steadily to above 230 mg/L, the average daily external water volume in the dry season decreased by 27.64%, and the sewage collection rate increased to 76%. The results indicate that the proposed framework can effectively support the quality and efficiency improvement of sewage pipeline networks in rainy cities of southern China, and provide a technical reference for similar cities.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3858-8

Lattice-Engineered High-Quality β-Ga2O3 Membranes for Memristive Applications Towards Image Encryption, Decryption, and Edge Detection

High-quality β-Ga2O3 membranes are pivotal for fabricating high-performance memristive devices. Here, vertical Ag/β-Ga2O3/Pt memristors built on high-crystalline-quality β-Ga2O3 membranes via lattice epitaxy engineering and a sacrificial-layer-assisted exfoliation strategy are reported. The resulting β-Ga2O3-based device demonstrates a high ON/OFF ratio exceeding 10^8, low SET/RESET voltages of 0.13 V/−0.11 V, low programming current of 10^-10 A, stable data retention beyond 4 × 10^4 s, and excellent subthreshold characteristics of ~0.47 mV/dec. Adjustable compliance current enables the coexistence of volatile and non-volatile switching modes. Additionally, the resistive switching versatility is predominantly governed by the migration of Ag ions, as supported by electrical characterizations and first-principles calculations. Furthermore, a β-Ga2O3 memristor-based circuit that functions as a reconfigurable and non-volatile exclusive OR (XOR) logic gate has been designed and simulated, enabling both image encryption/decryption and edge detection. This work not only demonstrates lattice-engineered, high-quality β-Ga2O3 membranes for fabricating advanced memristors but also extends their applicability to digital logic and reconfigurable image processing.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-4074-6

AI for Electrocatalytic Energy Conversion: From Atoms to Industry

Achieving carbon neutralization relies heavily on green hydrogen and electrochemical carbon-nitrogen cycles. However, the complexity of these systems and the cost of traditional Edisonian trial-and-error methods hinder rapid progress. Artificial intelligence (AI) has emerged as a transformative tool, enabling high-throughput data processing and dynamic adaptation. This review surveys the landscape of AI-driven electrochemistry, bridging the gap from atomic-scale design to industrial-scale implementation. Specifically, we focus on three areas: atomic structure-function decoding, fully automated “self-driving” laboratories, and macro-scale simulations for device durability. Furthermore, we elucidate the critical challenges in integrating AI with materials science. By mapping current trends and future directions, this work aims to unlock the full transformative potential of AI in next-generation energy storage and conversion.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4109-2

Ambient Fabrication of Over 19% Efficient Organic Solar Cells via Spontaneous Water-Spreading and Layer-by-Layer Deposition

The fabrication of high-efficiency organic solar cells (OSCs) under ambient conditions remains a formidable challenge due to the sensitivity of active layer morphology to environmental factors. We propose an innovative approach for air-processed devices that combines spontaneous water-spreading film formation with layer-by-layer (LBL) deposition. This method enables the fabrication of donor- and acceptor-dominant bulk heterojunction blend films near the anode and cathode interfacial layers, respectively, optimizing vertical phase separation and enhancing charge transfer efficiency. In the D18:L8-BO system, the device achieves a power conversion efficiency (PCE) of 19.02% with an exceptionally narrow efficiency distribution. Even for devices with an area of 1 cm2, a PCE of 16.56% is attained. After a 1000-hour decay test, the efficiency retains 84.1%. This novel method offers a promising pathway for advancing the industrial application of large-area, highly stable devices with narrow efficiency distribution under ambient conditions.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4048-x

Site-specific doping in mesoporous Co3O4 to enrich oxygen vacancies for efficient aromatic alkane oxidation

Selective oxidation of aromatic alkanes is a key reaction to produce high-value chemicals in the chemical industry. However, the strong C–H bonds and inert chemical properties of aromatic alkanes render the oxidation process difficult, thereby making the development of promising and sustainable catalysts highly desirable. Herein, a resin-assisted coordination co-assembly strategy is developed to synthesize heterometal-doped mesoporous Co3O4 with abundant oxygen vacancies, enabling precise control over both composition and pore structure. The site-specific Mn doping at octahedral sites of mesoporous Co3O4 promotes the formation of oxygen vacancy with enhanced activity. Density functional theory calculations further demonstrate that Mn doping in mesoporous Co3O4 reduces the oxygen vacancy formation energy, induces the electronic structure modifications and introduces the defect energy levels, finally promoting the efficient catalytic oxidation of a series of aromatic alkanes. Representatively, Mn-doped mesoporous Co3O4 exhibits remarkably outstanding catalytic activity, achieving 37% conversion of ethylbenzene and 97% selectivity for acetophenone under solvent-free conditions.

Prof. Nan He | Publications & Academic Profile | SinoGreenTech | SinoGreenTech