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Showing papers on "Raman spectroscopy published in 2022"


Journal ArticleDOI
08 Jul 2022-Science
TL;DR: In this paper , the authors proposed tuning electron and phonon localization by entropy manipulation, and demonstrated a route for improving the performance of high-entropy thermoelectric materials.
Abstract: The high-entropy concept provides extended, optimized space of a composition, resulting in unusual transport phenomena and excellent thermoelectric performance. By tuning electron and phonon localization, we enhanced the figure-of-merit value to 2.7 at 750 kelvin in germanium telluride–based high-entropy materials and realized a high experimental conversion efficiency of 13.3% at a temperature difference of 506 kelvin with the fabricated segmented module. By increasing the entropy, the increased crystal symmetry delocalized the distribution of electrons in the distorted rhombohedral structure, resulting in band convergence and improved electrical properties. By contrast, the localized phonons from the entropy-induced disorder dampened the propagation of transverse phonons, which was the origin of the increased anharmonicity and largely depressed lattice thermal conductivity. We provide a paradigm for tuning electron and phonon localization by entropy manipulation, but we have also demonstrated a route for improving the performance of high-entropy thermoelectric materials. Description Disordered but efficient Thermoelectric materials, many having relative simple compositions, convert heat into electricity. However, Jiang et al. found that adding more cations into a germanium tellurium–based material stabilized a phase with excellent thermoelectric properties. This high-entropy material has low thermal conductivity due to the cation disordering but improved symmetry that helps maintain good electrical properties. The material was used in several devices that showed a high thermoelectric efficiency. —BG A high-entropy material is an outstanding thermoelectric with a combination of delocalized electrons and localized phonons.

125 citations


Journal ArticleDOI
22 Apr 2022-ACS Nano
TL;DR: In this article , a Se-vacancy-rich WSe2-x catalyst in water-in-salt electrolyte (WISE) was used to achieve a high-efficiency NRR enabled by a Se2-X catalyst in WISE, achieving a faradaic efficiency of 62.5% and NH3 yield of 181.3 μg h-1 mg-1
Abstract: Electrocatalytic nitrogen reduction reaction (NRR) is a promising approach for renewable NH3 production, while developing the NRR electrocatalysis systems with both high activity and selectivity remains a significant challenge. Herein, we combine catalyst and electrolyte engineering to achieve a high-efficiency NRR enabled by a Se-vacancy-rich WSe2-x catalyst in water-in-salt electrolyte (WISE). Extensive characterizations, theoretical calculations, and in situ X-ray photoelectron/Raman spectroscopy reveal that WISE ensures suppressed H2 evolution, improved N2 affinity on the catalyst surface, as well as an enhanced π-back-donation ability of active sites, thereby promoting both activity and selectivity for the NRR. As a result, an excellent faradaic efficiency of 62.5% and NH3 yield of 181.3 μg h-1 mg-1 is achieved with WSe2-x in 12 m LiClO4, which is among the highest NRR performances reported to date.

87 citations



Journal ArticleDOI
TL;DR: In this article , an exfoliated polyimide COF composite (P-COF@SWCNT) was proposed as an advanced anode for potassium-ion batteries.
Abstract: Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite (P-COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single-walled carbon nanotubes as advanced anode for potassium-ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P-COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π-K+ effect, which is demonstrated by the DFT calculation and XPS, ex-situ FTIR, Raman. As a result, the prepared P-COF@SWCNT anode enables an incredibly high reversible specific capacity of 438 mA h g-1 at 0.05 A g-1 and extended stability. The structural advantage of P-COF@SWCNT enables more insights into the design and versatility of COF as an electrode.

75 citations


Journal ArticleDOI
TL;DR: In this article , a new progress in the preparation of graphene using CuI powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material, Co9S8-GDY-CuI, is reported.

62 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a review on the effects of B doping on different properties of carbon nanotubes (CNTs), on the potential applications of B doped CNTs, and draw the future roadmap for the research on B-CNT.

59 citations


Journal ArticleDOI
TL;DR: In this paper , the principles, design and applications of visible-light and near-infrared fluorescence and surface-enhanced Raman scattering in point-of-care testing and bio-imaging are reviewed.
Abstract: This article reviews the principles, design and applications of visible-light and near-infrared fluorescence and surface-enhanced Raman scattering in point-of-care testing and bio-imaging.

58 citations


Journal ArticleDOI
TL;DR: In this article , the surface reconstruction of Ni 5 P 4 @FeP was probed by in situ Raman spectroscopy and the structural instability of amorphous NiFe 2 O 4 led to partial reconstitution to Ni/FeOOH at high oxidation potentials.
Abstract: Oxygen evolution reaction (OER) is a key step for electrochemical water splitting and understanding the surface reconstruction of OER pre-catalysts is of vital importance. Herein, hybrid Ni 5 P 4 @FeP nanosheet arrays were evaluated as promising OER pre-catalysts. The dynamic surface evolution was probed by in situ Raman spectroscopy, which revealed that Ni 5 P 4 @FeP was rapidly reconstructed to NiFe 2 O 4 during the anodic scan. The structural instability of amorphous NiFe 2 O 4 led to partial reconstitution to Ni/FeOOH at high oxidation potentials. As-formed Ni/FeOOH@NiFe 2 O 4 hybrid with high structural reversibility was established as a truly active species, which exhibited excellent alkaline OER performance with a low overpotential of 205 and 242 mV under current densities of 10 and 100 mA cm −2 , respectively. This work provides a facile strategy to in situ construct an amorphous spinel/oxyhydroxide hybrid structure using electrochemical activation that holds strong promise for potential application in electrochemical water splitting and related energy devices. • Surface reconstruction of Ni 5 P 4 @FeP was probed by in situ Raman spectroscopy. • Ni 5 P 4 @FeP was oxidized to NiFe 2 O 4 and further to Ni/FeOOH at high potentials. • The real active intermediate was identified as Ni/FeOOH and NiFe 2 O 4 hybrid. • High structural reversibility between NiFe 2 O 4 and Ni/FeOOH was found. • As-formed amorphous NiOOH and NiFe 2 O 4 hybrid showed superior OER activity.

57 citations


Journal ArticleDOI
TL;DR: In this paper, a Fe-doped TiO2−x ultrathin nanosheet with abundant oxygen vacancies for H2S selective oxidation via a facile citric acid assisted hydrothermal process was reported.

55 citations


Journal ArticleDOI
TL;DR: In this paper , a modest solgel method has been employed to prepare the pure and Ag doped MnO2 nanoparticles and methodologically studied their physical, morphological, and photosensitive properties through XRD, TEM, EDAX, Raman, UV, PL and N2 adsorption - desorption study.
Abstract: A modest sol-gel method has been employed to prepare the pure and Ag doped MnO2 nanoparticles and methodologically studied their physical, morphological, and photosensitive properties through XRD, TEM, EDAX, Raman, UV, PL and N2 adsorption - desorption study. Tetragonal crystalline arrangement with spherical nanoparticles was found out through XRD and TEM studies. The EDAX studies further supported that formation Ag in the MnO2 crystal matrix. The bandgap energy of Ag doped MnO2 was absorbed through UV spectra. Photo -generated recombination process and surface related defects were further recognized by PL spectra. Through visible light irradiation, the photo - degradation of methyl orange (MO) and phenol dye solutions were observed. The optimum condition of (10 wt% of Ag) Ag doped MnO2 catalyst showed tremendous photocatalytic efficiency towards MO than phenol under same experimental study.

54 citations


Journal ArticleDOI
TL;DR: In this article , a novel Bi2O3/BiO2 heterojunction catalyst was synthesized via a molten alkali-assisted dealumination strategy and exhibited rich structural dynamics for an electrocatalytic CO2 reduction reaction (ECO2RR).
Abstract: Heterostructure engineering plays a vital role in regulating the material interface, thus boosting the electron transportation pathway in advanced catalysis. Herein, a novel Bi2O3/BiO2 heterojunction catalyst was synthesized via a molten alkali-assisted dealumination strategy and exhibited rich structural dynamics for an electrocatalytic CO2 reduction reaction (ECO2RR). By coupling in situ X-ray diffraction and Raman spectroscopy measurements, we found that the as-synthesized Bi2O3/BiO2 heterostructure can be transformed into a novel Bi/BiO2 Mott-Schottky heterostructure, leading to enhanced adsorption performance for CO2 and *OCHO intermediates. Consequently, high selectivity toward formate larger than 95% was rendered in a wide potential window along with an optimum partial current density of -111.42 mA cm-2 that benchmarked with the state-of-the-art Bi-based ECO2RR catalysts. This work reports the construction and fruitful structural dynamic insights of a novel heterojunction electrocatalyst for ECO2RR, which paves the way for the rational design of efficient heterojunction electrocatalysts for ECO2RR and beyond.

Journal ArticleDOI
TL;DR: In this article , an air-laser-based Raman spectrometer with high-frequency and high-temporal resolution was proposed for standoff surveillance of chemical and biochemical species.
Abstract: Among currently available optical spectroscopic methods, Raman spectroscopy has versatile application to investigation of dynamical processes of molecules leading to chemical changes in the gas and liquid phases. However, it is still a challenge to realize an ideal standoff coherent Raman spectrometer with which both high temporal resolution and high-frequency resolution can be achieved, so that one can remotely probe chemical species in real time with high temporal resolution while monitoring the populations in their respective rovibronic levels in the frequency domain with sufficiently high spectral resolution. In the present study, we construct an air-laser-based Raman spectrometer, in which near-infrared femtosecond (fs) laser pulses at 800 nm and cavity-free picosecond N2+ air-laser pulses at 391 nm generated by the filamentation induced by the fs laser pulses are simultaneously used, enabling us to generate a hybrid ps/fs laser source at a desired standoff position for standoff surveillance of chemical and biochemical species. With this prototype Raman spectrometer, we demonstrate that the temporal evolution of the electronic, vibrational, and rotational states of N2+ and the coupling processes of the rovibrational wave packet of N2 molecules can be probed.

Journal ArticleDOI
TL;DR: In this paper , air lasing naturally created inside a filament can serve as an ideal light source to probe Raman coherence excited by the femtosecond pump, producing coherent Raman signal with molecular vibrational signatures.
Abstract: Remote or standoff detection of greenhouse gases, air pollutants, and biological agents with innovative ultrafast laser technology attracts growing interests in recent years. Hybrid femtosecond/picosecond coherent Raman spectroscopy is considered as one of the most versatile techniques due to its great advantages in terms of detection sensitivity and chemical specificity. However, the simultaneous requirement for the femtosecond pump and the picosecond probe increases the complexity of optical system. Herein, we demonstrate that air lasing naturally created inside a filament can serve as an ideal light source to probe Raman coherence excited by the femtosecond pump, producing coherent Raman signal with molecular vibrational signatures. The combination of pulse self-compression effect and air lasing action during filamentation improves Raman excitation efficiency and greatly simplifies the experimental setup. The air-lasing-assisted Raman spectroscopy was applied to quantitatively detect greenhouse gases mixed in air, and it was found that the minimum detectable concentrations of CO2 and SF6 can reach 0.1% and 0.03%, respectively. The ingenious designs, especially the optimization of pump-seed delay and the choice of perpendicular polarization, ensure a high detection sensitivity and signal stability. Moreover, it is demonstrated that this method can be used for simultaneously measuring CO2 and SF6 gases and distinguishing 12CO2 and 13CO2. The developed scheme provides a new route for high-sensitivity standoff detection and combustion diagnosis.

Journal ArticleDOI
TL;DR: In this article , a green one-pot hydrothermal-carbonization method was used to transform kiwi fruit peels into valuable ki fruit peel carbon dots (KFP-CDs).
Abstract: Growing global biowaste and its environmental issues challenge the need for converting biowastes into a beneficial product. Among the biowaste, here kiwi fruit (Actinidia Deliciosa) peels are considered for the preparation of carbon dots (CDs). Using a green one-pot hydrothermal-carbonization method, kiwi fruit peels were effectively converted into valuable kiwi fruit peel carbon dots (KFP-CDs). The morphology, physio-chemical and optical properties of as-synthesized KFP-CDs were analyzed using various analytical techniques such as X-ray powder diffraction, Raman spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Ultraviolet-visible, and fluorescence spectroscopy. The KFP-CDs revealed a homogeneous spherical shape, monodispersed with an average size of 5 nm. The characterization confirms that KFP-CDs have functional groups such as -CN, -COOH, and -OH which are responsible for the easy dispersion of KFP-CDs in aqueous media. Without any preprocessing, KFP-CDs exhibit strong fluorescence upon exposure to UV light. Further, KFP-CDs displayed excitation-dependent fluorescence emission with a good quantum yield of about 18%. Thus by considering the excellent properties of KFP-CDs, KFP-CDs were used as fluorescent ink for drawing and writing without any capping/passivation agent. The pictures and words were instantaneously viewed when exposed to UV light. In addition, KFP-CDs tested for cell imaging in four human cell lines (normal and cancer cells) bestowed excellent biocompatibility and low cytotoxicity, which is important for the safe and long-term development of cellular imaging. The findings imply that KFP-CDs can be utilized as a cell labeling agent for mesenchymal stem cells, breast cancer, and thyroid cancer cells in vitro imaging. Thus, these observations revealed that investigating sustainable resource-based CDs can open up new avenues for tackling environmental issues.

Journal ArticleDOI
TL;DR: Inspired by the chromogenic reaction between starch and iodine, a structure confinement strategy is proposed to suppress polyiodide shuttling in Zn-I2 batteries by hiring starch, due to its unique double-helix structure as discussed by the authors .
Abstract: Aqueous Zn–iodine (Zn–I2) batteries have been regarded as a promising energy‐storage system owing to their high energy/power density, safety, and cost‐effectiveness. However, the polyiodide shuttling results in serious active mass loss and Zn corrosion, which limits the cycling life of Zn–I2 batteries. Inspired by the chromogenic reaction between starch and iodine, a structure confinement strategy is proposed to suppress polyiodide shuttling in Zn–I2 batteries by hiring starch, due to its unique double‐helix structure. In situ Raman spectroscopy demonstrates an I5−‐dominated I−/I2 conversion mechanism when using starch. The I5− presents a much stronger bonding with starch than I3−, inhibiting the polyiodide shuttling in Zn–I2 batteries, which is confirmed by in situ ultraviolet–visible spectra. Consequently, a highly reversible Zn–I2 battery with high Coulombic efficiency (≈100% at 0.2 A g−1) and ultralong cycling stability (>50 000 cycles) is realized. Simultaneously, the Zn corrosion triggered by polyiodide is effectively inhibited owing to the desirable shuttling‐suppression by the starch, as evidenced by X‐ray photoelectron spectroscopy analysis. This work provides a new understanding of the failure mechanism of Zn–I2 batteries and proposes a cheap but effective strategy to realize high‐cyclability Zn–I2 batteries.

Journal ArticleDOI
TL;DR: In this paper , the authors present the chronological development on B doped carbon nanotubes (CNTs) using different techniques with more emphasis on the chemical vapor deposition (CVD) method.

Journal ArticleDOI
TL;DR: In this article , a defect-rich Fe-doped ultrathin nanosheet with abundant oxygen vacancies was synthesized for H 2 S selective oxidation via a facile citric acid assisted hydrothermal process.

Journal ArticleDOI
TL;DR: Raman spectroscopy combined with machine learning techniques provides a rapid method for breast cancer analysis able to reveal differences in intracellular compositions and molecular structures among subtypes.

Journal ArticleDOI
TL;DR: In this article , the structural properties of AgNPs were systematically studied using X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and Raman measurement, which emanate the single-phase fcc structure of silver nanoparticles.
Abstract: Drug resistance in filamentous fungus to antifungal medicines is a huge problem in biomedical applications; so, an effective strategy for treating opportunistic fungal infections is needed. Mentha piperita is a very fascinating plant to treat a variety of ailments as home remedies. Eighteen strains of Aspergillus species were used for this study which are having a unique antifungal resistance profile in presence of silver nanoparticles (AgNPs). AgNPs were prepared, using an aqueous extract of M. Piperita and characterized it by various techniques. Structural properties of AgNPs were systematically studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and Raman measurement, which emanate the single-phase fcc structure of silver nanoparticles. The spherical nature and elemental analysis of as-synthesized AgNPs were confirmed using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy, respectively. The optical study has been analyzed using UV-Vis spectroscopy and band gap was calculated as 2.51 eV, using Tauc plot. To analyze and validate the good efficacy of the disc approach, antifungal activity of AgNPs nanoparticles in different concentrations against isolates was achieved in both disc and broth microdilution. The extracellular enzymatic activity of A. fumigatus was found to explore the precise impact of nanoparticles on fungal metabolism. The antifungal efficacy of AgNPs against all fungi was highly successful in disc method. The broth approach underlined the favorable results of the disc method. It provided more precise results in determining the minimum inhibition concentration (MIC), as well as the minimum effective concentration (MEC). A. fumigatus (AM6) enzymatic activity was boosted by AgNPs. Also, ß-galactosidase, ß-glucuronidase, and ß-glucosidase are necessary enzymes whose activity has been boosted. Consequently, M. piperita AgNPs can play a major and intriguing function against resistant Aspergillus species with a significant shift in the enzymatic activity profile of fungi due to this action.

Journal ArticleDOI
TL;DR: In this article , a two-dimensional negative-thermalexpansion phosphor of Sc 2 (MoO 4 ) 3 :Yb/Er was reported, which achieved a 45-fold enhancement of green upconversion (UC) luminescence and a 450-fold increase of near-infrared downshifting (DS) intensities upon raising the temperature from 298 to 773 K.
Abstract: Abstract Rare earth (RE 3+ )-doped phosphors generally suffer from thermal quenching, in which their photoluminescence (PL) intensities decrease at high temperatures. Herein, we report a class of unique two-dimensional negative-thermal-expansion phosphor of Sc 2 (MoO 4 ) 3 :Yb/Er. By virtue of the reduced distances between sensitizers and emitters as well as confined energy migration with increasing the temperature, a 45-fold enhancement of green upconversion (UC) luminescence and a 450-fold enhancement of near-infrared downshifting (DS) luminescence of Er 3+ are achieved upon raising the temperature from 298 to 773 K. The thermally boosted UC and DS luminescence mechanism is systematically investigated through in situ temperature-dependent Raman spectroscopy, synchrotron X-ray diffraction and PL dynamics. Moreover, the luminescence lifetime of 4 I 13/2 of Er 3+ in Sc 2 (MoO 4 ) 3 :Yb/Er displays a strong temperature dependence, enabling luminescence thermometry with the highest relative sensitivity of 12.3%/K at 298 K and low temperature uncertainty of 0.11 K at 623 K. These findings may gain a vital insight into the design of negative-thermal-expansion RE 3+ -doped phosphors for versatile applications.

Journal ArticleDOI
TL;DR: In this article , a two-dimensional MXene-based tin oxide (SnO 2 ) heterostructures with varying MXene wt% (10-40 wt%) using a facile hydrothermal method for room-temperature NO 2 detection are presented.
Abstract: Continuous exposure to high concentration of nitrogen dioxide (NO 2 ) severely affects the human respiratory system. Besides, NO 2 has been recently observed to foster COVID-19, resulting in increased fatality rate; thus highly selective gas sensors are required for detecting NO 2 at sub-ppb level. In this direction, we have synthesized two-dimensional MXene-based tin oxide (SnO 2 ) heterostructures with varying MXene wt% (10–40 wt%) using a facile hydrothermal method for room-temperature NO 2 detection. The synthesized heterostructures have been structurally, optically, and electrically characterized using a suite of characterization techniques, namely, X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Brunauer–Emmett–Teller techniques. The optimal incorporation of MXene in SnO 2 nanoparticles effectively decumulates them, increasing the specific surface area of heterostructures and thereby exposing large number of adsorption sites. 20-wt% SnO 2 /MXene heterostructures-based sensor exhibits nearly five times higher response (231%) toward 30-ppb NO 2 at room temperature with shorter response time (146 s) and recovery time (102 s) than pristine SnO 2 . Moreover, the sensor showed high selectivity, sensitivity, repeatability, reproducibility, and stable sensing response under humid conditions. The assembly of these results suggests that SnO 2 /MXene platform provides a pathway for realizing highly responsive NO 2 sensors. Herein, possible gas sensing mechanism based on the formation of SnO 2 /MXene heterostructures has been discussed. • MXene-incorporated SnO 2 heterostructures-based sensors have been fabricated using hydrothermal method. • Optimized MXene loading enhanced response and room-temperature selectivity towards NO 2 . • Fabricated sensors are capable of detecting ppb-level NO 2 with fast response and recovery time at room temperature. • SnO 2 /MXene Schottky junctions are found responsible for enhancing the gas sensing performance.

Journal ArticleDOI
TL;DR: In this article , a novel n-type phosphorus-doped bismuth oxychloride (P-BiOCl) photocatalyst was synthesized through facile one-step hydrothermal approach with sodium hypophosphite (NaH2PO2) addition, which is of extraordinarily high efficiency for tetracycline (TC) degradation under visible light.

Journal ArticleDOI
TL;DR: In this article , a kind of 2D semimetal material, molybdenum carbide (Mo2C) film, is prepared via a chemical vapor deposition (CVD) method, and the origin of SERS is investigated for the first time.
Abstract: The relatively weak Raman enhanced factors of semiconductor-based substrate limit its further application in surface-enhanced Raman scattering (SERS). Here, a kind of two-dimensional (2D) semimetal material, molybdenum carbide (Mo2C) film, is prepared via a chemical vapor deposition (CVD) method, and the origin of SERS is investigated for the first time. The detection limits of the prepared Mo2C films for crystal violet (CV) and rhodamine 6G (R6G) molecules are low at 10-6 M and 10-8 M, respectively. Our detailed theoretical analysis, based on density functional theory and the finite element method, demonstrates that the enhancement of the 2D Mo2C film is indeed CM in nature rather than the EM effects. Besides, the basic doping strategies are proposed to further optimize the SERS sensitivity of Mo2C for Fermi level regulation. We believe this work will provide a helpful guide for developing a highly sensitive semimetal SERS substrate.

Journal ArticleDOI
TL;DR: In this paper , an anti-swelling anion exchange ionomer (AEI) was proposed to optimize the local environment for promoting industrial-current-density CO2-to-C2+ electroreduction.
Abstract: CO2 electroreduction to high-energy-density C2+ products is highly attractive, whereas the C2+ selectivity under industrial current densities is still unsatisfying. Here, an anti-swelling anion exchange ionomer (AEI) was first proposed to optimize the local environment for promoting industrial-current-density CO2-to-C2+ electroreduction. Taking the anti-swelling AEI-modified oxide-derived Cu nanosheets as an example, in situ Raman spectroscopy and contact angle measurements revealed that the OH--accumulated -N(CH3)3+ groups and anti-swelling backbone of AEI could synergistically regulate the local pH level and water content. In situ Fourier-transform infrared spectroscopy and theoretical calculations demonstrated that the higher local pH value could lower the energy barrier for the rate-limiting COCO* hydrogenated to COCOH* from 0.08 to 0.04 eV, thereby boosting the generation of C2+ products. Owing to the anti-swelling backbone, the optimized water content of 3.5% could suppress the competing H2 evolution and hence facilitate the proton-electron transfer step for C2+ production. As a result, the anti-swelling AEI-modified oxide-derived Cu nanosheets achieved a C2+ Faradaic efficiency of 85.1% at a current density up to 800 mA cm-2 with a half-cell power conversion efficiency exceeding 50%, outperforming most reported powder catalysts.

Journal ArticleDOI
TL;DR: In this paper, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage, which guarantees structural robustness and accelerates ions/electrons transportation.

Book ChapterDOI
Xiang Wang1, Guo-Kun Liu1, Ren Hu1, Maofeng Cao1, Sen Yan1, Yi-Fan Bao1, Bin Ren1 
01 Jan 2022
TL;DR: In this article, the authors guide the reader through the principles of SERS, including the electromagnetic field enhancement and chemical enhancement, with emphasis on the surface plasmon resonance effect.
Abstract: Surface-enhanced Raman spectroscopy (SERS) has manifested its power in clinical applications, benefitted from the ability to provide fingerprint information even down to single-molecule level. In this chapter, we will guide you through the principles of SERS, including the electromagnetic field enhancement and chemical enhancement, with emphasis on the surface plasmon resonance effect. Some practical issues, such as spectral analysis and selection of SERS substrates, will also be briefed from the mechanistic understanding. The main purpose of this chapter is to provide you the necessary background to understand the literatures and start your own journey of applying SERS for clinical diagnosis.

Journal ArticleDOI
TL;DR: In this paper , the authors used Raman spectroscopy and machine learning techniques to simplify and accelerate the process used to distinguish normal from breast cancer cells and classify breast cancer subtypes.

Journal ArticleDOI
TL;DR: In this article , N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage, which guarantees structural robustness and accelerates ions/electrons transportation.

Journal ArticleDOI
TL;DR: In this paper , a novel Al/Nd co-doping method of Ba 4 Nd 9.33 + z/3 Ti 18− z Al 4 z /3 O 54 (BNT-A, 0 ⩽ z ⌽ 2) was proposed to improve the dielectric properties through structural and defect modulation.
Abstract: Abstract Low-loss tungsten-bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation (5G) communication technology. In this work, a novel Al/Nd co-doping method of Ba 4 Nd 9.33 Ti 18 O 54 (BNT) ceramics with a chemical formula of Ba 4 Nd 9.33+ z /3 Ti 18− z Al z O 54 (BNT-AN, 0 ⩽ z ⩽ 2) was proposed to improve the dielectric properties through structural and defect modulation. Together with Al-doped ceramics (Ba 4 Nd 9.33 Ti 18− z Al 4 z /3 O 54 , BNT-A, 0 ⩽ z ⩽ 2) for comparison, the ceramics were prepared by a solid state method. It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping. As the doping amount z increased, the relative dielectric constant ( ε r ) and the temperature coefficient of resonant frequency ( τ f ) of the ceramics decreased, and the Q×f values of the ceramics obviously increased when z ⩽ 1.5. Excellent microwave dielectric properties of ε r = 72.2, Q×f = 16,480 GHz, and τ f = +14.3 ppm/°C were achieved in BNT-AN ceramics with z = 1.25. Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics. It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies ( $${\rm{V}}_{\rm{O}}^{ \cdot \cdot }$$ V O ), demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.

Journal ArticleDOI
TL;DR: In this paper , a series of Mn4+-activated double perovskite Gd2ZnTiO6 phosphors were prepared to develop novel, bifunctional sensors of temperature and pressure.