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Topological insulators are a new class of quantum materials that are characterized by robust topological surface states (TSSs) inside the bulk insulating gap, which hold great potential for applications in quantum information and spintronics as well as thermoelectrics. One major obstacle is the relatively small size of the bulk bandgap, which is typically around 0.3eV for the known topological insulator materials (ref. and references therein). Here we demonstrate through ab initio calculations that a known superconductor BaBiO sub(3) (BBO) with a T sub(c) of nearly 30K (refs , ) emerges as a topological insulator in the electron-doped region. BBO exhibits a large topological energy gap of 0.7eV, inside which a Dirac type of TSSs exists. As the first oxide topological insulator, BBO is naturally stable against surface oxidization and degradation, distinct from chalcogenide topological insulators. An extra advantage of BBO lies in its ability to serve as an interface between TSSs and superconductors to realize Majorana fermions for future applications in quantum computation.

Infrared detection technology plays an important role in remote sensing, imaging, monitoring, and other fields. So far, most infrared photodetectors are based on InGaAs and HgCdTe materials, which are limited by high fabrication costs, complex production processes, and poor compatibility with silicon-based readout integrated circuits. This hinders the wider application of infrared detection technology. Therefore, reducing the cost of high-performance photodetectors is a research focus. Colloidal quantum dot photodetectors have the advantages of solution processing, low cost, and good compatibility with silicon-based substrates. In this paper, we summarize the recent development of infrared photodetectors based on mainstream lead chalcogenide colloidal quantum dots.

Two-dimensional (2D) materials with multiphase, multielement crystals such as transition metal chalcogenides (TMCs) (based on V, Cr, Mn, Fe, Cd, Pt and Pd) and transition metal phosphorous chalcogenides (TMPCs) offer a unique platform to explore novel physical phenomena. However, the synthesis of a single-phase/single-composition crystal of these 2D materials via chemical vapour deposition is still challenging. Here we unravel a competitive-chemical-reaction-based growth mechanism to manipulate the nucleation and growth rate. Based on the growth mechanism, 67 types of TMCs and TMPCs with a defined phase, controllable structure and tunable component can be realized. The ferromagnetism and superconductivity in FeXy can be tuned by the y value, such as superconductivity observed in FeX and ferromagnetism in FeS2 monolayers, demonstrating the high quality of as-grown 2D materials. This work paves the way for the multidisciplinary exploration of 2D TMPCs and TMCs with unique properties.A competitive-chemical-reaction-based growth mechanism by controlling the kinetic parameters can easily realize the growth of transition metal chalcogenides and transition metal phosphorous chalcogenides with different compositions and phases.

In this work, the optical bandgap variations of the chalcogenide glass Ge15Se70Te5Sb10 in bulk, thin film, and nanocolloid form were explored. The bulk glass was synthesized through a conventional melt quenching method, while the thin film was produced by thermal evaporation, and the nanocolloid was obtained through solution-processed techniques. Optical bandgap measurements for each form, performed via UV-VIS-NIR spectroscopy, revealed a notable blue shift in the bandgap when transitioning from bulk to film and then to nanocolloid. The shift in optical band gap with dimensionality of the material underscores the tunable nature of the bandgap in chalcogenide glasses, presenting potential applications in photonic devices.

Supercapacitors revealing excellent power density have arisen as the most promising candidates for supporting the major developments in energy storage devices. Supercapacitor attracts many emerging mobile devices for addressing energy storage and harvesting issues. The supercapacitor is similar to a conventional capacitor. Moreover, many researchers studied the improvement of energy and power density so that they can be applied extensively. The electrochemical performance of supercapacitor depends on various factors like electrode materials, electrolyte, and the range of voltage used. Most researchers mainly focused on the development of new electrode materials which yield better performance for the application of supercapacitors. This review work summarizes the introduction of supercapacitors and the recent advanced development of a variety of electrode materials in supercapacitors and production methods. In particular, transition metal chalcogenide–based electrode materials are focused here. Also, this review précises the improvement of the electrochemical performance of supercapacitor by incorporating or doping highly active materials like MWCNT, graphene, CNT, reduced graphene oxide, metal-based compounds, and polymers. The enhancement of specific capacity by altering the morphology and developing electrode with new morphological structures is deeply discussed in this review. Recently, trimetallic chalcogenides and its composites are emerged as new promising electrode materials which deliver large specific capacitance with excellent cycling stability and rate performance have also been reported here.

HighlightsUnique “Janus” interfacial assemble strategy of 2D MXene nanosheets was proposed firstly.Ternary heterostructure consisting of high capacity transitional metal chalcogenide, high conductive 2D MXene and N rich fungal carbonaceous matrix was achieved for larger radius Na/K ions storages.The highly accessible surfaces and interfaces of the strongly coupled 2D based ternary heterostructures provide superb surficial pseudocapacitive storages for both Na and K ions with low energy barriers was verified.Combining with the advantages of two-dimensional (2D) nanomaterials, MXenes have shown great potential in next generation rechargeable batteries. Similar with other 2D materials, MXenes generally suffer severe self-agglomeration, low capacity, and unsatisfied durability, particularly for larger sodium/potassium ions, compromising their practical values. In this work, a novel ternary heterostructure self-assembled from transition metal selenides (MSe, M = Cu, Ni, and Co), MXene nanosheets and N-rich carbonaceous nanoribbons (CNRibs) with ultrafast ion transport properties is designed for sluggish sodium-ion (SIB) and potassium-ion (PIB) batteries. Benefiting from the diverse chemical characteristics, the positively charged MSe anchored onto the electronegative hydroxy (–OH) functionalized MXene surfaces through electrostatic adsorption, while the fungal-derived CNRibs bonded with the other side of MXene through amino bridging and hydrogen bonds. This unique MXene-based heterostructure prevents the restacking of 2D materials, increases the intrinsic conductivity, and most importantly, provides ultrafast interfacial ion transport pathways and extra surficial and interfacial storage sites, and thus, boosts the high-rate storage performances in SIB and PIB applications. Both the quantitatively kinetic analysis and the density functional theory (DFT) calculations revealed that the interfacial ion transport is several orders higher than that of the pristine MXenes, which delivered much enhanced Na+ (536.3 mAh g−1@ 0.1 A g−1) and K+ (305.6 mAh g−1@ 1.0 A g−1 ) storage capabilities and excellent long-term cycling stability. Therefore, this work provides new insights into 2D materials engineering and low-cost, but kinetically sluggish post-Li batteries.

Owing to stable spatial framework and large electrochemical interface, self-supported transition metal chalcogenides have been actively explored in renewable energy fields, especially in oxygen evolution reaction (OER). Here, we review the research progress of self-supported transition metal chalcogenides (including sulfides, selenides, and tellurides) for the OER in recent years. The basic principle and evaluation parameters of OER are first introduced, and then the preparation methods of transition metal chalcogenides on various self-supporting substrates (including Ni foam (NF), carbon cloth (CC), carbon fiber paper (CFP), metal mesh/plate, etc.) are systematically summarized. Subsequently, advanced optimization strategies (including interface and defect engineering, heteroatom doping, edge engineering, surface morphology engineering, and construction of heterostructure) are introduced in detail to improve the inherent catalytic activity of self-supported electrocatalysts. Finally, the challenges and prospects of developing more promising self-supported chalcogenide electrocatalysts are proposed.

Glass microresonators with whispering gallery modes (WGMs) have a lot of diversified applications, including applications for sensing based on thermo-optical effects. Chalcogenide glass microresonators have a noticeably higher temperature sensitivity compared to silica ones, but only a few works have been devoted to the study of their thermo-optical properties. We present experimental and theoretical studies of thermo-optical effects in microspheres made of an As2S3 chalcogenide glass fiber. We investigated the steady-state and transient temperature distributions caused by heating due to the partial thermalization of the pump power and found the corresponding wavelength shifts of the WGMs. The experimental measurements of the thermal response time, thermo-optical shifts of the WGMs, and heat power sensitivity in microspheres with diameters of 80–380 µm are in a good agreement with the theoretically predicted dependences. The calculated temperature sensitivity of 42 pm/K does not depend on diameter for microspheres made of commercially available chalcogenide fiber, which may play an important role in the development of temperature sensors.

A sandwich-type sensitive voltammetric immunosensor for breast cancer biomarker human epidermal growth factor receptor 2 (HER2) detection was prepared. The electrochemical immunosensor was developed based on gold nanoparticles decorated copper-organic framework (AuNPs/Cu-MOF) and quaternary chalcogenide with platinum-doped graphitic carbon nitride (g-C 3 N 4 ). Cu 2 ZnSnS 4 nanoparticle (CZTS NP) quaternary chalcogenide with platinum (Pt)-doped g-C 3 N 4 composite (Pt/g-C 3 N 4 ) was tagged as CZTS NPs/Pt/g-C 3 N 4 . AuNPs/Cu-MOF composite was successfully synthesized by amidation reaction between AuNPs functionalized with amino group and Cu-MOFs containing carboxylic acid. After the conjugations of primer HER2 antibody and antigen HER2 protein to AuNPs/Cu-MOF as sensor platform, CZTS NPs/Pt/g-C 3 N 4 composite was prepared by one-pot hydrothermal method. After immune reaction of 30 min, the prepared HER2 immunosensor was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The developed immunosensor showed high sensitivity with a detection limit of 3.00 fg mL −1 . Additional properties of the voltammetric immunosensor are high selectivity, stability, reproducibility, and reusability. Graphical abstract