Nanoscale infrared spectroscopy

Transition metal dichalcogenides exhibit rich phase diagrams dominated by the interplay of superconductivity and charge density waves, which often result in anomalies in the electric transport properties. Here, we employ the ionic gating technique to realize a tunable, non-volatile organic ion intercalation in bulk single crystals of molybdenum disulphide (MoS2). We demonstrate that this gate-driven organic ion intercalation induces a strong electron doping in the system without changing the pristine 2H crystal symmetry and triggers the emergence of a re-entrant insulator-to-metal transition. We show that the gate-induced metallic state exhibits clear anomalies in the temperature dependence of the resistivity with a natural explanation as signatures of the development of a charge-density wave phase which was previously observed in alkali-intercalated MoS2. The relatively large temperature at which the anomalies are observed (∼150 K), combined with the absence of any sign of doping-induced superconductivity down to ∼3 K, suggests that the two phases might be competing with each other to determine the electronic ground state of electron-doped MoS2.

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“…The spatial distribution of the intercalants was investigated by nanoscale infrared spectroscopy [ 77 , 78 ]. Figure 3 a shows a

AFM topography map of a freshly-cleaved MoS

crystal.…”

Section: Resultsmentioning

confidence: 99%

Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation

2022

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“…NanoIR ® [ 273 , 274 ] is a new technique, which has a great potential to analyze NPs. Conventional IR technology provides information on functional groups, whereas atomic force microscopy (AFM) offers information on surface morphology.…”

Section: Mixed Ag–cu Nps and Agcu Nanoalloysmentioning

confidence: 99%

Antimicrobial Properties of the Ag, Cu Nanoparticle System

Fan

Yahia

Sacher

2021

Biology

104

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Microbes, including bacteria and fungi, easily form stable biofilms on many surfaces. Such biofilms have high resistance to antibiotics, and cause nosocomial and postoperative infections. The antimicrobial and antiviral behaviors of Ag and Cu nanoparticles (NPs) are well known, and possible mechanisms for their actions, such as released ions, reactive oxygen species (ROS), contact killing, the immunostimulatory effect, and others have been proposed. Ag and Cu NPs, and their derivative NPs, have different antimicrobial capacities and cytotoxicities. Factors, such as size, shape and surface treatment, influence their antimicrobial activities. The biomedical application of antimicrobial Ag and Cu NPs involves coating onto substrates, including textiles, polymers, ceramics, and metals. Because Ag and Cu are immiscible, synthetic AgCu nanoalloys have different microstructures, which impact their antimicrobial effects. When mixed, the combination of Ag and Cu NPs act synergistically, offering substantially enhanced antimicrobial behavior. However, when alloyed in Ag–Cu NPs, the antimicrobial behavior is even more enhanced. The reason for this enhancement is unclear. Here, we discuss these results and the possible behavior mechanisms that underlie them.

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“…The wavelength or wavenumber-dependent optical and chemical properties can be obtained via the collected light with amplitude and phase properties [ 36 , 37 ]. More basic principles on the theory for AFM-IR and IR s-SNOM techniques are available in [ 34 , 38 , 39 , 40 , 41 , 42 ].…”

Section: Overview Of Afm-ir and Ir S-snommentioning

confidence: 99%

Recent Progress on the Characterization of Cellulose Nanomaterials by Nanoscale Infrared Spectroscopy

Zhu

Zhou

et al. 2021

Nanomaterials

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Researches of cellulose nanomaterials have seen nearly exponential growth over the past several decades for versatile applications. The characterization of nanostructural arrangement and local chemical distribution is critical to understand their role when developing cellulose materials. However, with the development of current characterization methods, the simultaneous morphological and chemical characterization of cellulose materials at nanoscale resolution is still challenging. Two fundamentally different nanoscale infrared spectroscopic techniques, namely atomic force microscope based infrared spectroscopy (AFM-IR) and infrared scattering scanning near field optical microscopy (IR s-SNOM), have been established by the integration of AFM with IR spectroscopy to realize nanoscale spatially resolved imaging for both morphological and chemical information. This review aims to summarize and highlight the recent developments in the applications of current state-of-the-art nanoscale IR spectroscopy and imaging to cellulose materials. It briefly outlines the basic principles of AFM-IR and IR s-SNOM, as well as their advantages and limitations to characterize cellulose materials. The uses of AFM-IR and IR s-SNOM for the understanding and development of cellulose materials, including cellulose nanomaterials, cellulose nanocomposites, and plant cell walls, are extensively summarized and discussed. The prospects of future developments in cellulose materials characterization are provided in the final part.

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Nanoscale infrared spectroscopy

Cited by 20 publications

References 0 publications

Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation

Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation

Antimicrobial Properties of the Ag, Cu Nanoparticle System

Recent Progress on the Characterization of Cellulose Nanomaterials by Nanoscale Infrared Spectroscopy

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