2D semiconductors are attracting considerable interest for neuromorphic electronics for their strong light-matter interaction, defect-mediated charge dynamics, and suitability for energy-efficient devices. Among them, tin diselenide (SnSe2) combines Earth abundance, environmental stability, high carrier mobility and persistent photoconductivity that make it a compelling candidate for multifunctional optoelectronic synapses. Here, we investigate multilayer SnSe2 field-effect transistors and demonstrate gate-tunable optoelectronic plasticity. Systematic measurements as a function of temperature, illumination power, and gate bias reveal that the device photoresponse is dominated by trap-assisted photogating. The interplay between fast and slow recombination channels produces a persistent photocurrent (PPC) that can be finely tuned by the gate voltage. Negative gate bias enhances charge separation and prolongs PPC, enabling long-term potentiation, while positive gate bias accelerates recombination and suppresses persistence, yielding short-term memory. Furthermore, short gate voltage pulses enable reversible suppression of persistent photocurrent, allowing controlled switching between short- and long-term memory states. Under repetitive optical stimulation, the devices exhibit cumulative learning and memory retention with high reproducibility. These results highlight SnSe2 as a robust platform for optoelectronic neuromorphic devices. By exploiting interfacial trap states and gate control, SnSe2-based transistors emulate essential synaptic functionalities with excellent stability, offering new opportunities for 2D-material-enabled scalable neuromorphic hardware.
We describe the scientific objectives and instrument design of the ASPIICS coronagraph launched aboard the Proba-3 mission of the European Space Agency (ESA) on 5 December 2024. Proba-3 consists of two spacecraft in a highly elliptical orbit around the Earth. One spacecraft carries the telescope, and the external occulter is mounted on the second spacecraft. The two spacecraft fly in a precise formation during 6 hours out of 19.63 hour orbit, together forming a giant solar coronagraph called ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun). Very long distance between the external occulter and the telescope (around 144 m) represents an increase of two orders of magnitude compared to classical externally occulted solar coronagraphs. This allows us to observe the inner corona in eclipse-like conditions, i.e. close to the solar limb (down to 1.099 Rs) and with very low straylight. ASPIICS will provide a new perspective on the inner solar corona that will help solve several outstanding problems in solar physics, such as the origin of the slow solar wind and physical mechanism of coronal mass ejections.
Functionalized gold nanoparticles (AuNPs) have emerged as versatile platforms in therapeutic research, yet their specific roles in regenerative medicine, particularly in modulating prokaryotic and eukaryotic cell responses, enhancing antioxidant defense, and supporting tissue repair mechanisms, remain insufficiently elucidated. In this study, we have obtained gold nanoparticles initially functionalized with the well-established antioxidant lipoic acid and subsequently with thiosalicylic acid. Their final modification with the 6-amino-chromen-2-one, a coumarin derivative with recognized antioxidant and pharmacological relevance, generated novel composite systems, distinguished by enhanced biological performance. The novel structures have been comprehensively characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), and thermal analysis. Their biological properties were evaluated through antimicrobial and anti-adherence assays against standard and clinical strains, as well as antioxidant and biocompatibility (hemolytic/anti-hemolytic/cytotoxicity) assays. The findings highlight the strong therapeutic potential of functionalized AuNPs, demonstrating enhanced antimicrobial efficacy, antioxidant protection, and cytocompatibility. Their capacity to reduce oxidative stress and combat microbial infections show promise for advanced biomedical applications, such as controlled drug delivery and tissue regeneration.
DNA microarray technology requires optimizing substrate properties and DNA labeling strategies for enhanced detection. This study introduces an improved biosensor platform utilizing nanoporous silicon (pSi) substrates with a glycidyl ether of bisphenol A (SU-8) polymer coating, decorated with graphene quantum dots (GQDs), to amplify fluorescent signals. We compared two methods for obtaining labeled single-stranded DNA: Lambda exonuclease digestion of phosphorylated PCR products and asymmetric PCR (aPCR) with Cy5-labeled nested primers. Our findings demonstrate that pSi biochips with 7 nm pores covered by thicker SU-8 layers (700-750 nm) provide 52% higher signal relative to the standard deviation. The aPCR labeling method demonstrated superior performance, yielding significantly stronger signals -4.06 mean signal intensity and a standard deviation of 0.16. Decorating the SU-8 coating with 6 nm GQDs further amplified the signal intensity by 11%. These findings highlight the need to optimize DNA labeling and utilize nanostructured heterostructures for enhanced microarray performance, with implications for personalized medicine and diagnostics.
In recent years, carbon nano-onions (CNOs), together with their functionalized derivatives, nanocomposites, and nanohybrids, have attracted increasing attention as sensing materials for monitoring relative humidity (RH), gases, and temperature. Their concentric graphitic structure provides good electrical conductivity, chemical and thermal stability, accessible surface sites, tunable surface chemistry, and compatibility with polymer matrices and flexible substrates. This review highlights recent advances in the synthesis and functionalization of CNOs and examines their integration into chemiresistive, surface acoustic wave, flexible, and printed sensing platforms. Particular attention is devoted to pristine and oxidized CNOs, heteroatom-doped materials, and composites incorporating hydrophilic or conducting polymers, metal oxides, and other functional fillers. CNO-based sensing layers demonstrate room-temperature (RT) detection of RH, hydrogen, ammonia, acetone, ethanol, isopropanol, carbon dioxide, hydrogen sulfide, and other volatile organic compounds. In addition, CNOs and CNO–polymer films exhibit significant temperature-dependent resistance variations, supporting their potential use in flexible and wearable temperature sensors. Although several CNO-based devices show superior performance in sensitivity, response, recovery characteristics, mechanical flexibility, and low-power operation, the studies on CNOs available in the literature remain limited compared with those on carbon nanotubes, graphene derivatives, and other carbonaceous materials. Further progress on CNO-based structures requires reproducible, large-scale synthesis; improved film uniformity and selectivity; standardized testing; compensation for temperature–humidity cross-sensitivity; and long-term stability studies. This review concludes by highlighting research directions to bridge the gap between laboratory prototypes and commercially viable CNO-based sensing devices.
