Electronically inert Te ensures superior stability of Nb2SiTe4: An ab initio defect study

Organic-inorganic formamidinium lead triiodide (FAPbI3) hybrid perovskite quantum dots (QDs) have garnered considerable attention in the photovoltaic field due to their narrow bandgap, exceptional environmental stability, and prolonged carrier lifetime. Unfortunately, their insulating ligands and surface vacancy defects pose significant obstacles to efficient charge transfer across device interfaces. In this work, an electrostatic harmonization strategy at the interface using a donor-acceptor dipole molecular attachment to achieve enhanced charge separation capabilities on the QD surface is ventured. On the basis of theoretical study and experimental evaluation, it has gained a comprehensive understanding of dipole-induced electronic restructuring at the quantum dot interfaces. It reveals that 3-fluoro-4-iodopyridine as a dipole source with appropriate energy levels and a high dipole moment effectively fills surface iodine vacancies (VI-), leading to rapid separation of photoexcited charge carriers. Particularly enhanced hole mobility and hydrophobicity are achieved through strong electronegative effects of fluorine and iodine. Consequently, the FAPbI3 QD solar cells achieve a power conversion efficiency as high as 14.11% with exceptional long-term stability in ambient. These perceptions provide effective interface engineering means for the hybrid perovskite QDs to advance their potential in high-performance optoelectronic applications.

The site-dependent photoluminescence of activators can be regulated by the sintering atmosphere, coexistence conditions, and especially cation codoping, which have been intensively studied for design and optimization of optical functional materials. Here, first-principles calculations are performed to determine the regulation of the site occupancy, valence states and optical transitions of Mn activators via codoping in yttrium aluminum garnets (YAGs), which contain three different cation sites. Without any codopants, Mnoct3+ dominates in defect concentration and photoluminescence, which can hardly be tuned by the sintering atmosphere or coexistence conditions of YAGs with other competing compounds. With the low formation energy of Ca2+, Be2+, Mg2+, and Sr2+ codopants and in an oxidation sintering atmosphere, the Fermi energy is lowered and the concentration and luminescence of Mnoct4+ are enhanced. Na+ and Li+ codopants with relatively high formation energy have little influence on tuning the Fermi energy. Then with the low formation energy of Ti4+, Si4+ codopants and in a reducing sintering atmosphere, the Fermi energy is lifted and the luminescence of Mndod2+ and Mnoct2+ is enhanced as a result of increased concentrations. The proposed first-principles scheme, with general applicability and encouraging predictive power, provides an effective approach for elucidating the effects of codoping impurities on the design and optimization of optical materials.

Glassy hydrogels, which maintain a distinctive glassy state at ambient temperature, are appealing for engineering applications. Nevertheless, the existing glassy hydrogels often suffer from inferior strength, inadequate stiffness, and environmental stability caused by weak physical cross-linking. Herein, we present an ultrastiff and ultrastrong glassy hydrogel by introducing robust coordination bonds into a network composed of polyacrylic acid (PAA) and polyvinyl alcohol (PVA), using a copper acetate-assisted strategy. The presence of acetate anions creates a relatively alkaline environment, which deprotonates the carboxyl groups of PAA. This deprotonation exposes carboxylate groups that readily coordinate with copper ions, establishing a densely cross-linked network in the glassy state. The resultant glassy hydrogel exhibits record-breaking Young's modulus (469.7MPa), tensile strength (19.2MPa), and exceptional environmental stability. Moreover, the reversible softening and vitrification induced by the breakage and reforming of coordination bonds endows glassy hydrogel with structural programmability, allowing for the construction of integrated auxetic hydrogel (IAH). The IAH demonstrates enhanced mechanical properties compared to the auxetic skeleton alone while maintaining a negative Poisson's ratio over a wide strain range of 0-29%. This study provides a promising engineering route for the development of advanced glassy hydrogels.

First-principles study of group V and VII impurities in SnS2

We perform the first-principles calculations for the formation energies of cation antisite defects in Y3Al5O12. This method provides precise values of formation energy and thus allows us to estimate the defect concentration. The calculations show that YAl,16a is the most predominant antisite defects at high temperature for the single crystal growth and its concentration significantly decreases at low temperature for the single-crystalline film preparation. The calculated defect concentrations are quantitatively accord with the experimental estimation. AlY has high formation energy even with excess Al2O3, which indicates AlY is energetically unfavorable and the defect process is not intrinsic but nonstoichiometry.

Manipulating perovskite nanocrystals (PNCs) with nanoscale patterning and structural integrity is critical for their integration into advanced optoelectronic devices. However, conventional patterning methods often compromise the structural integrity, detrimental to optical properties of PNCs. Here, a dual‐role strategy is reported that combines PNCs nanopatterning and in situ synthesis directly on versatile substrates, effectively circumventing the post‐synthesis processing damage. A complementary dual‐role mechanism, leveraging molecular coordination and network confinement, enables precise regulation over PNCs growth, yielding tunable crystallite sizes from 20 to 200 nm. Notably, the PNCs exhibit exceptional environmental stability, with photoluminescence intensity enhanced by approximately sixfold after 2000 h of exposure to ambient air. Furthermore, the fabrication of light‐emitting nanocrystal gratings using nanoimprint lithography is demonstrated, achieving sub‐40 nm resolution, precise alignment accuracy, and high aspect ratios, faithfully reproducing the predefined surface morphologies. Tunable optical responses are realized by customizing the PNCs array geometry, thus facilitating amplified directional radiation for sophisticated nanophotonic and optoelectronic applications. These findings establish a robust platform for integrated nano‐optoelectronics, opening avenues for advanced photonic devices and quantum optical applications.

Stress is a universal experience impacting mental and physical health. However, no precise, objective wearable tool exists for continuous, long-term stress monitoring, which is essential for understanding stress-related health outcomes. To address this gap, we introduce SQC-SAS, a multimodal wearable device that simultaneously and continuously measures multiple physiological and molecularstress biomarkers for quantitative stress assessment and sub-classification. This device features exceptional environmental stability, reusability, and fully wireless data and power operation. Machine learning enables data-driven stress assessment and classification across multiple stress states, allowing biomarker profiles to be correlated with each state. Its wristband-like design enables continuous stress monitoring and real-time visualization. We envision our wearable will greatly advance precise, objective stress assessment and monitoring, offering unprecedented capabilities and laying the foundation for personalized interventions and a deeper understanding of stress-related outcomes.

The compound 2,4,6-trichlorophenol poses significant risks to both the aquatic environment and human health. Its inherent persistence and stability present challenges in achieving complete purification, thus warranting its inclusion as a priority pollutant. The present study reports the development of an amphiphilic small-molecule compound that self-assembles into nanovesicles exhibiting remarkable adsorption and photodegradation capabilities. Through the synergistic effects of hydrogen bonding, van der Waals forces, π-π interactions, and electrostatic interactions, these vesicles efficiently adsorb 2,4,6-trichlorophenol from aqueous solutions within 1 min while demonstrating exceptional environmental stability and broad applicability. Upon self-assembly into vesicles, not only are more adsorption sites exposed, but charge separation and migration within the vesicles are also facilitated. Through the synergistic effects of adsorption and photodegradation, complete removal of 2,4,6-trichlorophenol in aqueous solution can be achieved within 8 h while exhibiting excellent recycling capability. This approach offers a viable strategy for designing and synthesizing pure organic photodegradable materials.

2D Ruddlesden-Popper (RP) hybrid perovskite ferroelectrics have emerged as a promising class of direct X-ray detection materials. However, their intrinsic van der Waals gaps result in weak interlayer interactions that destabilize the layered motifs impacting the stability of the X-ray detector. Thus, it is crucial but remains toughly challenge to enhance interlayer interactions exploring stable RP perovskite ferroelectric X-ray detectors. Here, halogen bond is proposed to enhance the interlayer interactions of RP perovskite ferroelectrics obtaining a 2D trilayered ferroelectric, (BrPA)2(EA)2Pb3Br10 (BEPB, BrPA = 3-bromopropylaminium; EA = ethylammonium). Strikingly, the strong Br···Br halogen bonds lock cations to the inorganic skeletons, and C─H···Br hydrogen bonds bridge adjacent spacing sheets, which effectively improves structural stability and suppresses ion migration. The typical P-E hysteresis loops reveal its concrete ferroelectric behaviors, giving a large polarization of ≈7.3 µCcm-2. Consequently, the BEPB-based X-ray detector results in a high sensitivity of 562.6 µC Gy-1 cm-2 at 0 V bias, and most importantly, it exhibits low baseline drift and exceptional environmental stability. As far as is known, halogen bond strengthening 2D multilayered ferroelectric to achieve stable and efficient X-ray detection is unprecedented, which sheds light on the future design of stable optoelectronic devices toward practical applications.

To address aerodynamic efficiency reduction and safety risks caused by wind turbine blade icing in cold regions, this study proposes a low‐energy composite anti‐icing/de‐icing system based on graphite paper and superhydrophobic coatings. The superhydrophobic coating is fabricated from waste silicone rubber derived from discarded insulators. This system synergistically combines the passive anti‐icing capability of the superhydrophobic coating and the active de‐icing performance of electrothermal heating, significantly enhancing the ice prevention and removal efficiency. The experimental results demonstrate that the prepared system surface achieves a contact angle of 157 ± 3° with a rolling angle of 1.6 ± 0.3°, effectively delaying ice formation to 717 s. In the electrothermal mode, the surface temperature reaches 100.8 °C, enabling complete ice removal within 58 s. Robustness tests, including UV aging, icing/de‐icing cycles, and antiwear tests, maintain contact angles above 150°, confirming exceptional environmental stability. The composite system exhibits reliable long‐term performance under extreme conditions while demonstrating advantages in energy efficiency, sustainability, and material recyclability. This study provides an innovative strategy for wind turbine blade anti‐icing/de‐icing and resource utilization of waste polymer materials.

The term "nanozyme" refers to a nanomaterial possessing enzymatic capabilities, and in recent years, the field of nanozymes has experienced rapid advancement. Nanozymes offer distinct advantages over natural enzymes, including ease of production, cost-effectiveness, prolonged storage capabilities, and exceptional environmental stability. In this review, we provide a concise overview of various common applications of nanozymes, encompassing the detection and removal of pollutants such as pathogens, toxic ions, pesticides, phenols, organic contaminants, air pollution, and antibiotic residues. Furthermore, our focus is directed towards the potential challenges and future developments within the realm of nanozymes. The burgeoning applications of nanozymes in bioscience and technology have kindled significant interest in research in this domain, and it is anticipated that nanozymes will soon become a topic of explosive discussion.

2D magnetic oxides have emerged as a pivotal class of materials due to their exceptional environmental stability and tunable magnetic functionalities. Recent advancements in the synthesis of 2D magnetic oxides have opened unprecedented opportunities for next-generation technologies, ranging from spintronics to quantum computing. This review provides a comprehensive analysis of synthesis methodologies and magnetic phenomena in these materials. We first classify 2D magnetic oxides based on structural dimensionality (layered/non-layered) and compositional complexity (binary/ternary systems). Subsequently, we detail advanced vapor-phase synthesis strategies, encompassing additive-assisted growth, spatially confined epitaxy, phase/interface engineering, and heteroatom/heterostructure integration. The intrinsic magnetic properties-including room-temperature ferromagnetism and thickness-dependent spin ordering-are rigorously validated through multimodal characterization techniques such as vibrating sample magnetometry (VSM), magnetic force microscopy (MFM), magneto-optic Kerr effect (MOKE), and superconducting quantum interference device (SQUID) measurements. In addition, we discuss the critical challenges associated with wafer-scale integration and air stability, and propose strategies for designing robust 2D oxide architectures with tailored magnetic responses, providing a roadmap for both fundamental research and device innovation.

Field-effect transistors are crucial components for modern electronics, generating significant research and profitable interest. Metal halide perovskites have recently emerged as a pioneering active material in solar cells, generating interest in their potential use in other electronic and (opto)electronic devices, including field-effect transistors and phototransistors. However, before they can be commercialized, they still face significant challenges owing to their immanent instabilities with respect to heat, moisture, and light. In contrast, due to their exceptional environmental stability, the newly emerging two-dimensional Ruddlesden–Popper type perovskites have garnered significant recognition. The current state of the field is covered in this review article, as are the problems, and a perspective for the scenarios of perovskite field-effect transistors. The effects of temperature, light, and measurement conditions are taken into account, as well as the physics of the device and the fundamental mechanisms that drive these devices, such as ion migration and ionic defects. Subsequently, the performance of perovskite transistors and phototransistors described so far is analyzed and critically evaluated. Finally, the major roadblocks to perovskite transistor advancement are identified and explored. The lessons learned from other perovskite optoelectronic devices are investigated in order to address these obstacles and bring these devices closer to industrial implementation.

The two most desired properties for photo-detection using a strained-layer superlattice (SLS) are high native point defect (NPD) formation energies and absence of mid-gap levels. In this Letter we use first-principles calculations to study the formation energies of NPDs. First we validate the numerical method by comparing the calculated defect formation energies with measured values reported in the literature. Then we calculate the formation energy of various NPDs in a number of InAs-GaSb SLS systems. From the calculated defect formation energies in SLS relative to that in constituent bulk material, the probability of defect presence in SLS can be inferred if we know the growth conditions of SLS with respect to those of the bulk material. Since the defects with much higher formation energy in SLS will be difficult to form, their energy levels in the SLS mini-gap will have little effect on device performance, even if the defect states lie in mid-gap. Together with our calculated defect energy level results, we can identify promising SLS designs for high-performing photodetectors.

Developing mixed-anion semiconductors for solar fuel production has inspired extensive interest, but the nitrohalide-based photocatalyst is still in shortage. Here we report a layered nitro-halide β-ZrNBr with a narrow band gap of ca. 2.3 eV and low defect density to exhibit multifunctionalities for photocatalytic water reduction, water oxidation and CO2 reduction under visible-light irradiation. As confirmed by the results of electron paramagnetic resonance (EPR) and density functional theory (DFT) calculations, the formation of anion vacancies in the nitro-halide photocatalyst was inhibited due to its relatively high formation energy. Furthermore, performance of β-ZrNBr can be effectively promoted by a simple exfoliation into nanosheets to shorten the carrier transfer distance as well as to promote charge separation. Our work extends the territory of functional photocatalysts into the nitro-halide, which opens a new avenue for fabricating efficient artificial photosynthesis.