Intrinsically white organic polarized emissive semiconductors
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Anthrone/XLPE: an adaptive charge capture intelligent insulation material for advanced electric power transmission
The degradation of electrical insulation is mainly attributed to local defects. Although incorporating organic small molecules into dielectric polymers promotes the insulation strength, accurate suppression of defect development is a long-term and formidable challenge. Here we utilize the adaptive charge capture methodology to achieve precise defect suppression, leading to a 123% increase in the initiation voltage of electrical trees in anthrone/cross-linked polyethylene, significantly outperforming existing dielectric polymers and polymer composites. A significant observation is the confinement of charge at the interface between the anode and cross-linked polyethylene in anthrone/cross-linked polyethylene, generating a reverse inherent electric field near the interface and reducing the internal electric field strength of cross-linked polyethylene by up to 18%. These findings not only open avenues for further exploration of materials for ultra-high voltage cables but also play a crucial role in the commercialization and practical application of organic semiconductors in insulation dielectrics.
A robust organic hydrogen sensor for distributed monitoring applications
Hydrogen is an abundant and clean energy source that could help to decarbonize difficult-to-electrify economic sectors. However, its safe deployment relies on the availability of cost-effective hydrogen detection technologies. We describe a hydrogen sensor that uses an organic semiconductor as the active layer. It can operate over a wide temperature and humidity range. Ambient oxygen p-dopes the organic semiconductor, which improves hole transport, and the presence of hydrogen reverses this doping process, leading to a drop in current and enabling reliable and rapid hydrogen detection. The sensor exhibits a high responsivity (more than 10,000), fast response time (less than 1 s), low limit of detection (around 192 ppb) and low power consumption (less than 2 μW). It can operate continuously for more than 646 days in ambient air at room temperature. We show that the sensor outperforms a commercial hydrogen detector in realistic sensing scenarios, illustrating its suitability for application in distributed sensor networks for early warning of hydrogen leaks and preventing explosions or fires.
Encrypted metasurfaces with inherent asymmetric-like digitized keys under decoupled near-field parameters
The modulation of the light field by metasurfaces in near-field remains constrained by the coupling of cross-polarization components. This limits the storage space for ciphertexts with orthogonal polarization states. Our proposal introduces a transmission model with layered-control theory, which realizes decoupled states of anti-diagonal entries of meta-molecules in Jones matrices, granting us the ability to modulate cross-polarization components, thus providing a feasible platform for packet transmission or other creative algorithms. Two interlinked distinct logics are strategically constructed in the loading and detecting information processes, achieving asymmetric-like encryptions. It conceals encrypted messages within spatial light field distributions with precise logical rules which can be derived into form of logical expressions as mathematical keys, mitigating the risk of direct data extraction from metasurfaces. This research refines the matching of different light fields and information, expands the modulation parameters and introduces digitized keys for encrypted metasurfaces.
Genome-wide analysis identifies novel shared loci between depression and white matter microstructure
Depression, a complex and heritable psychiatric disorder, is associated with alterations in white matter microstructure, yet their shared genetic basis remains largely unclear. Utilizing the largest available genome-wide association study (GWAS) datasets for depression (N = 674,452) and white matter microstructure (N = 33,224), assessed through diffusion tensor imaging metrics such as fractional anisotropy (FA) and mean diffusivity (MD), we employed linkage disequilibrium score regression method to estimate global genetic correlations, local analysis of [co]variant association approach to pinpoint genomic regions with local genetic correlations, and conjunctional false discovery rate analysis to identify shared variants. Our findings revealed that depression showed significant local genetic correlations with FA in 37 genomic regions and with MD in 59 regions, while global genetic correlations were weak. Variant-level analysis identified 78 distinct loci jointly associated with depression (25 novel loci) and FA (35 novel loci), and 41 distinct loci associated with depression (17 novel loci) and MD (25 novel loci). Further analyses showed that these shared loci exhibited both concordant and discordant effect directions between depression and white matter traits, as well as distinct yet overlapping hemispheric patterns in their genetic architecture. Enrichment analysis of these shared loci implicated biological processes related to metabolism and regulation. This study provides evidence of a mixed-direction shared genetic architecture between depression and white matter microstructure. The identification of specific loci and pathways offers potential insights for developing targeted interventions to improve white matter integrity and alleviate depressive symptoms.
Switching on and off the spin polarization of the conduction band in antiferromagnetic bilayer transistors
Antiferromagnetic conductors with suitably broken spatial symmetries host spin-polarized bands, which lead to transport phenomena commonly observed in metallic ferromagnets. In bulk materials, it is the given crystalline structure that determines whether symmetries are broken and spin-polarized bands are present. Here we show that, in the two-dimensional limit, an electric field can control the relevant symmetries. To this end, we fabricate a double-gate transistor based on bilayers of van der Waals antiferromagnetic semiconductor CrPS4 and show how a perpendicular electric displacement field can switch the spin polarization of the conduction band on and off. Because conduction band states with opposite spin polarizations are hosted in the different layers and are spatially separated, these devices also give control over the magnetization of the electrons that are accumulated electrostatically. Our experiments show that double-gated CrPS4 transistors provide a viable platform to create gate-induced conductors with near unity spin polarization at the Fermi level, as well as devices with a full electrostatic control of the total magnetization of the system.
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