SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4257-y
Hafnia-based ferroelectrics exhibit a distinctive reverse size effect and exceptional scalability, positioning them as critical candidates for CMOS-compatible non-volatile memory and ferroelectric transistors, with substantial promise for advancing hardware acceleration in artificial intelligence and large-data storage technologies. However, their practical deployment is constrained by a longstanding dilemma: the difficulty in simultaneously stabilizing metastable polar phases and ensuring long-term reliability under the high electric fields required for polarization switching. This review reinterprets this challenge through the lens of defect physics and advocates a paradigm shift from stochastic, disorder-mediated defect incorporation toward ordered, multiscale defect engineering. We systematically discuss the collective influence of point defects, line defects, planar defects, and defect-coupled structures on the phase stability, switching kinetics, and failure mechanisms in hafnia-based ferroelectrics. Controlling oxygen-vacancy states, engineering dopants via Fermi-level and chemical pressure, deploying periodic dislocation arrays, designing topological domain walls, functionalizing interfaces, and leveraging flexoelectric strain gradients constitute the core strategic toolkit. Through such ordered defect architectures, scalable performance metrics, including high remanent polarization, low coercive field, fast switching speed, and endurance exceeding 10^12 cycles, become attainable. These approaches establish a set of design principles for next-generation low-power, high-reliability ferroelectric electronics.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025120801
The interaction between microplastic-derived dissolved organic matter (PSDOM) and iron oxides in soil environments can modulate its photosensitization effects, yet the underlying mechanisms remain elusive. This study investigated the influence of hematite with distinct morphologies—flake-shaped (HNPs) and cubic (HNCs)—on the photosensitization of polystyrene-derived dissolved organic matter (PSDOM). Under 500 W mercury lamp irradiation, both hematite morphologies promoted PSDOM degradation, with HNCs exhibiting superior performance: total organic carbon (TOC) decreased from 18.4 mg·L−1 to 12.3 mg·L−1 within 90 min, compared to 13.3 mg·L−1 for HNPs. Three-dimensional fluorescence spectroscopy indicated that hematite alters the humification process, thereby modifying photosensitization. Electron paramagnetic resonance (EPR) spectroscopy identified the generation of singlet oxygen (1O2), hydroxyl radicals (·OH), and carbon-centered radicals (CH3C(=O)OO·). HNCs significantly enhanced 1O2 production, while HNPs favored ·OH generation; both inhibited CH3C(=O)OO· formation. Quantitative analysis via high-performance liquid chromatography revealed that the steady-state concentration of 1O2 was highest with HNCs, reaching 2.80 times that of the PSDOM control, whereas ·OH concentration peaked with HNPs at 1.98 times the control. Notably, the steady-state concentration of 1O2 was approximately three orders of magnitude higher than that of ·OH. These findings elucidate the morphology-dependent role of hematite in PSDOM photosensitization, providing mechanistic insights into the environmental fate of microplastic-derived organic matter in complex soil systems.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3776-9
Organic thin-film transistors (OTFTs) are fundamental building blocks for flexible electronics, offering mechanical flexibility, biocompatibility, chemical tunability, and compatibility with large-area, cost-effective fabrication. However, their widespread adoption in high-density integrated systems is hindered by the thermionic limit of carrier injection, which constrains the subthreshold swing (SS) to a minimum of 60 mV/dec at room temperature, posing a critical barrier to ultra-low-power operation. In a groundbreaking study published in Nature Electronics, Deng et al. report the realization of organic thin-film tunnel transistors (OTFTTs) that decisively break this Boltzmann tyranny. The breakthrough is enabled by an interfacial molecule decoupling strategy, introducing a high-ionization-energy molecular interlayer, N,N'-bis(2-phenylethyl)perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI), between the high-work-function metal oxide (MoO3) source and the p-type organic semiconductor (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT)) channel. This interlayer passivates the interface, minimizing interfacial gap states and alleviating Fermi-level pinning, thereby creating a clean heterojunction with a lowered tunneling barrier. This facilitates efficient quantum mechanical band-to-band tunneling for carrier injection at low supply voltages, instead of relying on traditional thermionic emission. The OTFTTs exhibit sub-thermionic SS values below 60 mV/dec, enabling high electrical performance at low operating voltages. This work provides a viable pathway for beyond-thermionic electronics, with potential applications in flexible displays, wearable health monitors, brain-computer interfaces, and distributed sensor networks, addressing the critical challenge of power dissipation in flexible systems.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202607019
This study investigated the effects of biochar on volatile fatty acids (VFAs) production, biogas composition, physicochemical properties of the fermentation broth, and microbial community structure through batch anaerobic fermentation experiments using food waste as the substrate. The results demonstrated that the addition of biochar (1 g/L) significantly enhanced VFAs production, with the total VFAs concentration reaching 2150 mg/L in the biochar group, which was 30.2% higher than that of the control group (1651 mg/L). Acetic acid, propionic acid, and butyric acid were identified as the primary VFAs components. In the fermentation system, biochar exhibited a notable pH-buffering effect, stabilizing the fermentation environment. Additionally, its porous structure adsorbed ions during the fermentation process, resulting in a slightly lower electrical conductivity compared to the control group. Microbial community analysis revealed that biochar addition enriched key acidogenic bacteria, such as Defluviitoga and norank_f__Family_XI, optimizing the microbial community structure, and thereby facilitating organic acid production. In summary, biochar effectively promoted the efficient accumulation of VFAs during anaerobic fermentation of food waste by improving the fermentation microenvironment, enhancing system buffering capacity, and regulating microbial community composition. These findings provide theoretical support for sustainable enhancement of resource utilization of food waste.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3878-5
Borides, exhibiting complex bonding and structural diversity, are promising materials in the fields of ambient superconductivity and hard materials. Although some cage borides with either superhard or superconductivity have been reported, there is still a lack of systematic tuning of the metal centers in regulating their superconductivity and hardness. This study investigates the impact of s-block/d-block metal elements on the superconducting and hardness properties of boron cage lattices under ambient conditions. Using first-principles calculations, we predict a novel class of stable cage-like metallic borides, MB8 (M = Na, Be, Mg, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) characterized by metal embedded in B–B sublattices composed of 4/8 member B-rings. Superconductivity, hardness, and electronic structure calculations indicate that s-block and d-block metals influence the p-orbital occupancy of B bands, affecting both the electron-phonon coupling (EPC) constant and the bonding strength. In general, within the I422 MB8 (B16 cage) structural family investigated here at ambient pressure, s-block metals enhance the EPC constant (λ) and favour higher superconducting critical temperature (Tc) but weaken the hardness, whereas d-block metals contribute the opposite. Therefore, the Tc of NaB8 reached 24.4 K, which is among the highest values reported for boron cage compounds, while ZrB8 from d-block metals exhibits the highest hardness (21.9 GPa) among. This work proposes a pathway for designing novel superconductors with robust mechanical performance under ambient pressure and elucidates the distinct roles of s-block and d-block metals in modulating the superconductivity and hardness of cage-like borides.