Carbon nanotube are exceptional mechanical resonators. Indeed, they are extremely light, with masses in the range of ~ag (1 ag = 10-18g). In addition, as bottom-up materials, they do not suffer from surface defect as their top-down counterparts (MEMS etched from silicon or nitride substrates). From these 2 features stems their exquisite mass sensitivity as demonstrated by Chaste et al[1] with a sensitivity of 1.4 yg in a cryogenic environment. Yet, this sensitivity was reported to be much worse at room temperature, about 25 zg[2]. This has hindered the use of CNTs as sensors in real-life applications. In this work, we propose a unique set-up to track in real time the vibrations of a individual single-walled CNT (SWCNTs) at room temperature. It allows us to demonstrate a record mass sensitivity of 0.2 yg +/- 0.17 yg (1 yg = 10-24 g, the mass of a single proton).We carefully investigated the noise mechanisms that could be limiting the sensitivity: set-up noise, interaction with the gas phase and Brownian motion to name only the most important ones. We found that our device operates closely to the Brownian noise limit and is not limited by external sources of noise. Surprisingly, increasing the pressure up to 35 mbar (after which we could not detect the motion due to viscous damping) does not seem to degrade the sensitivity, which might be preserved up to ambient pressure. Finally, yet importantly, the exquisite sensitivity observed here is similar for several devices, making it a reliable and reproducible feature. This opens up the possibility to perform single-molecule sensing, in various contexts such as biological applications, mass spectrometry or surface science[1,3].[1] J. Chaste, A. Eichler, J. Moser, G. Ceballos, R. Rurali, A. Bachtold (2012). A nanomechanical mass sensor with yoctogram resolution, Nat. Nano, 7, 5, 301-304.[2] B. Lassagne, D. Garcia-Sanchez, A. Aguasca, A. Bachtold (2008). Ultrasensitive mass sensing with a nanotube electromechanical resonator, Nano. Let., 8, 11, 3735 – 3738.[3] P. Robin, L. Bocquet (2023). Nanofluidics at the crossroads, Soft Cond. Matt., preprint.

This study investigates the influence of interlayer cations on the thermodynamics and sorption mechanisms of water in a reference Wyoming montmorillonite. The behaviour of the montmorillonite exchanged with monovalent cations (Li + , Na + , K + , Rb + , Cs + ) or divalent cations (Mg 2+ , Ca 2+ , Ba 2+ ) is compared. The analysis combines X-ray diffraction (XRD), water sorption isotherms at various temperatures and mid-infrared spectroscopy. Li + , Mg 2+ and Ca 2+ promote greater water uptake and swelling, whereas K + , Rb + and Cs + significantly limit these processes. The behaviour of Na + and Ba 2+ stands out, demonstrating intermediate water uptake and high swelling. Mid-infrared spectral analysis supports these observations. It is shown that a cation’s effect on water uptake and swelling correlates best with the product of its elementary charge and ionic radius rather than with other properties such as the electrostatic potential, solvation enthalpy or chemical hardness. However, differences in isotherm shapes, hysteresis between adsorption and desorption and the variation of isosteric heat with water content suggest the presence of two distinct sorption mechanisms: one involving Li + , Cs + , Mg 2+ , Ca 2+ and Ba 2+ , and another involving Na + , K + and Rb + . These findings indicate that isotherm shape and swelling alone do not directly reflect water uptake capacity. These findings thus outline that the chaotropic (structure-breaking) or kosmotropic (structure-making) nature of the cations, along with the complex interplay between cation hydration and TOT layer attraction, may explain the complex observed differences.

We have produced thin film samples of cubic ZnS by the chemical bath method. These samples were synthesized using zinc chloride, thiourea, sodium citrate and ammonia solutions at varied deposition time from 24h to 96h. X-ray diffraction (XRD), transmittance and photoluminescence (PL) analyses provided the physical characteristics of cubic ZnS films with crystal plane orientations (2 0 0) and (2 2 2), lattice parameters of 5.648 Å and an atomic plane distance d=1.412 Å. The grain size calculed are 16.53 nm and 17.12 nm. PL revealed deep defects in the gap with peaks in the visible, with prominent emissions at 430 nm (blue) and 510 nm (green). The measured transmittance of the films is 88.6%.

It has recently been shown that Terahertz sensors can effectively detect the spin resonances of Dirac fermions in graphene. The associated photovoltaic measurement technique allows for the investigation of the intrinsic spin-orbit coupling in graphene as well as its topological properties from microwave to Terahertz frequencies. In this work, using graphene/MoS₂-based Field-Effect Transistors, we observed a magnetic resonance photovoltage signal in the Gigahertz range that is independent on the gate bias. The dispersion of the associated spin-flip transitions remains intriguingly unaffected by the MoS₂ layer. In parallel, the spin-related signal consistently appears as a drop in photovoltage, regardless of the signal's polarity or origin, whether it is due to plasma wave rectification or thermoelectric effects. This behavior is interpreted as a decrease in the system's spin polarization due to spin-dependent recombination or scattering of photocarriers. Understanding the various photovoltaic signals in highly sensitive Gigahertz/Terahertz sensors paves the way for exploring spin-dependent mechanisms in two-dimensional quantum materials, influenced by proximity effects such as spin-orbit coupling, topology, and magnetism.

This study addresses the challenge of analyzing the growth kinetics of carbon nanotubes using in-situ homodyne polarization microscopy (HPM) by developing an automated deep learning (DL) approach. A Mask-RCNN architecture, enhanced with a ResNet-50 backbone, was employed to recognize and track individual nanotubes in microscopy videos, significantly improving the efficiency and reproducibility of kinetic data extraction. The method involves a series of video processing steps to enhance contrast and used differential treatment techniques to manage low signal and fast kinetics. The DL model demonstrates consistency with manual measurements and increased throughput, laying the foundation for statistical studies of nanotube growth. The approach can be adapted for other types of in-situ microscopy studies, emphasizing the importance of automation in high-throughput data acquisition for research on individual nano-objects.