Добірка наукової літератури з теми "Te Nanowire (TeNW)"

Ultrathin Te nanowire (NW) and Au nanosheet (NS) was assembled as two-dimensional macroscale films. The AuNS–Ag₂TeNW–AuNS device is applicable to wearable resistive switching device due to their paper-like flexibility.

Large scale and highly ordered thermoelectric BixTe1-x (0.4 ≤ x ≤ 0.7) nanowire arrays were successfully fabricated by cathodic electrolysis into porous anodic alumina membrane (AAM) templates in aqueous solution. The structure of the nanowires was characterized by X-ray diffraction and selected-area electron diffraction (SAED). Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results show that the nanowires are smooth and uniform with the diameters of about 50 nm and lengths up to tens of micrometers. Energy dispersive spectroscopy (EDS) was used to check the exact stoichiometry of as-prepared samples. The results reveal that the atomic ratio between Bi and Te can be modulated effectively by controlling the concentration of the electrolyte solution. The synthesis of high quality BixTe1-x nanowires with controllable x is significant for optimizing the thermoelectric performance.

Large-area randomly-oriented silicon nanowires (SiNWs) were synthesized using Au-coated p-type Si (100) substrates via the solid-liquid-solid (SLS) process under different growth conditions. Microstructural studies on the NWs produced showed that straight crystalline nanowires of large aspect ratios were generally obtained at a growth temperature of 1000°C along with some worm-like amorphous structures. Large-area vertically aligned silicon nanowire (SiNW) arrays on p-type (001) Si substrates were also synthesized in an aqueous solution containing AgNO3 and HF by self-selective electroless etching. Diameters of the SiNWs produced from both methods varied from 50 nm to 350 nm and their lengths generally extended from several to approximately a few tens of µm depending on the growth conditions used. Te-Si and Bi2Te3-Si core-shell structures were subsequently obtained via galvanic displacement of SiNWs in acidic HF electrolytes containing HTeO2+ and Bi3+/HTeO2+ ions. The reactions were basically a nanoelectrochemical process due to the difference in redox potentials between the materials. The modified SiNWs of core-shell structures had roughened surface morphologies and, therefore, higher surface-to-bulk ratios compared to unmodified SiNWs. They should have potential applications in sensors, photovoltaic and thermoelectric nanodevices. Microstructural studies on the SiNWs and core-shell structures produced are presented using various microscopy, diffraction and probe-based techniques for characterization.

A single step surfactant-assisted hydrothermal route has been developed for the synthesis of zigzag silver telluride nanowires with diameter of 50–60 nm and length of several tens of micrometers. Silver nitrate (AgNO3) and sodium tellurite (Na2TeO3), are the precursors and polyvinylpyrrolidone (PVP) is used as surfactant in the presence of the reducing agent, that is, hydrazine hydrate (N2H4·H2O). In addition to the zigzag nanowires a facile hydrothermal reduction-carbonization route is proposed for the preparation of uniform core-shell Ag2Te/C nanowires. In case of Ag2Te/C synthesis process the same precursors are employed for Ag and Te along with the ethylene glycol used as reducing agent and glucose as the carbonizing agent. Morphological and compositional properties of the prepared products are analyzed with the help of scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy, respectively. The detailed formation mechanism of the zigzag morphology and reduction-carbonization growth mechanism for core-shell nanowires are illustrated on the bases of experimental results.

Advances in the technology of wearable electronic devices have necessitated much research to meet their requirements, such as stretchability, sustainability, and maintenance-free functioning. In this study, we developed an ultrathin all-fiber triboelectric nanogenerator (TENG)-based electronic skin (TE-skin) with high stretchability, using electrospinning and spraying, whereby the silver nanowire (Ag NW) electrode layer is deposited between two electrospinning thermoplastic polyurethane (TPU) fibrous layers. Due to its extraordinary stretchability and prominent Ag NW conductive networks, the TE-skin exhibits a high sensitivity of 0.1539 kPa−1 in terms of pressure, superior mechanical property with a low-resistance electrode of 257.3 Ω at a strain of 150%, great deformation recovery ability, and exceptional working stability with no obvious fluctuation in electrical output before and after stretching. Based on the outstanding performances of the TE-skin, an intelligent electronic glove was fabricated to detect multifarious hand gestures. Moreover, the TE-skin has the potential to record human motion for real-time physiological signal monitoring, which provides promising applications in the fields of flexible robots, human-machine interaction, and multidimensional sports monitoring in next-generation electronics.

Au-GaAs metal-semiconductor composite microstructures have been prepared by an anisotropic etching of n-GaAs (100) wafers doped with Te (1016 to 1017 cm-3) with subsequent photostimulated chemical deposition of noble metal (Au) on formed semiconductor quasigratings. The microrelief topology of GaAs surface is controlled by the anisotropic etching conditions. Au metal was deposited on the structured GaAs surface as randomly placed nanoparticles of various shape and size and/or nanowires on the top of the hills of formed semiconductor microstructure. As the number of Au nanoparticles increases, they tend to localize on the ledges of the GaAs microrelief forming a system of approximately parallel nanowires. Obtained periodic structures with submicron to microns periods without Au nanoparticles and with deposited nanoparticles have been studied by means of scanning electron microscopy, optical spectroscopy (photoluminescence spectroscopy at room temperature), and photoelectric measurements. The decrease of the relative intensity of main photoluminescence band for samples with Au nanostructures compared to ones without nanoparticles deposition and simultaniously changes of the shape of photocurrent spectra of Au-GaAs microstructures have been observed. Such correlation in behaviour of measured spectra make formed Au-GaA metal-semiconductor microstructures perspective for the application in plasmonic photovoltaics.

Realizing high-throughput, low-cost perovskite solar cell (PSC) manufacturing is highly sought-after in photovoltaic research in recent years. PSCs can be fabricated using inexpensive and scalable solution-deposition methods, such as slot-die coating, blade coating, or spray coating, that can be performed in open air or under inert gas conditions and are compatible with high-throughput, roll-to-roll (R2R) manufacturing. To fully achieve R2R manufacturing of PSCs, it is important to also consider the flexible transparent electrode (TE). PET/ITO is a commonly used substrate for making flexible PSCs. When optimizing transparent conducting materials, there is a tradeoff between sheet resistance (Rsh) and optical transparency. PET/ITO substrates with high Rsh have high transparency and smoother ITO surfaces, compared to PET/ITO substrates with low Rsh, which have low transparency and higher surface roughness, indicating thicker ITO films. ITO is brittle and tends to crack under mechanical stress or bending, which is further exacerbated when using a thicker ITO layer. It is desired to have a thin ITO film with low Rsh, high optical transparency, and smooth surface roughness. Because commercial PET/ITO substrates are made with slow (~1 m/min) vacuum deposition processes, they tend to be expensive. Therefore, it would be advantageous to develop a high-throughput, R2R compatible, solution-deposition approach for fabricating the TE on PET substrates. To achieve this, two key processes must be developed: A solution-deposition process that enables uniform coating of the TE on PET and a post-deposition annealing process that is compatible with the low-temperature PET and high speed of R2R manufacturing. While various solution-deposition processes, such as those listed above, can achieve the desired web speed of > 30 m/min, there is still a need to improve the post-deposition annealing step. One promising post-deposition processing technique is intense-pulsed-light processing, also known as photonic curing. Photonic curing delivers short (0.01 – 100 ms) pulses of broadband (200 – 1500 nm) light from a xenon flash lamp to the samples. Any materials in the sample stack that absorb light will convert the impinging light pulse into heat within the sample, which drives changes in the sample (calcination, phase change, crystallization, etc.). Photonic curing has three main advantages over thermal annealing: 1. Faster processing speed (milliseconds or seconds). 2. Compatibility with plastic substrates. 3. Smaller physical footprint and less wasted energy. Since the light pulses are on for a short time, the intensity can be high while the total energy delivered to the sample is low. During the photonic curing process, the absorbed light causes the TE precursor film to selectively and quickly (microseconds – milliseconds) heat up, while the PET substrate underneath heats up less and slower (seconds). Because the thin film is a few orders-of-magnitude thinner than the PET substrate, the heat generated and transferred from the thin film does not cause significant substrate heating. This allows high-temperature processing in the top layers of the sample stack, while keeping the bottom plastic substrate temperature low. In this work, a hybrid TE material is fabricated on PET substrates using photonic curing. The hybrid TE material contains a layer of silver nanowires (AgNWs) and a layer of metal-oxide (ITO, IZO, etc.). The AgNWs increase the light absorbed by the film during the photonic curing process, which leads to higher processing temperatures, possibly improving the conversion of the metal-oxide layer. The AgNWs also enhance the electrical conductivity of the final TE layer after photonic curing. A AgNW and metal-oxide bilayer is formed by spin coating each solution onto the PET substrate sequentially followed by a single photonic curing process. We use average optical transmittance (Tavg) from 400 to 700 nm and average Rsh to evaluate the TE performance. The following photonic curing parameters are varied to optimize Tavg (maximize) and Rsh (minimize): Pulse voltage, pulse envelope, number of micro-pulses, duty cycle, number of pulses, and pulse repetition rate. Preliminarily, we also observe a significant impact on the TE properties by the volume of AgNW deposited during the spin coating deposition step. Using dispense volumes of 80 µL and 20 µL, we achieve samples with Tavg = 73%, Rsh = 19 Ω/sq, and roughness = 9 nm, and Tavg = 83%, Rsh = 58 Ω/sq, and roughness = 5.6 nm, respectively, after photonic curing. Fig. 1 a-d shows SEM, AFM, sample schematic, and AFM line-cuts of the photonic cured hybrid TE sample, respectively. Figure 1

Enhancing the reversibility of Li is crucial for extending the cycle life of Li‐limited anode‐free lithium–sulfur (Li–S) batteries. Incorporating tellurium (Te) in the system has proven to be highly effective by its reaction with polysulfides and forming a passivating interfacial layer on Li surface, which reduces the Li‐ion diffusion barrier. However, due to the poor utilization of Te, a significant amount of Te is required to improve cell cycling performance. To address this, nanowire‐structured Te (TeNW) is synthesized via a hydrothermal method and applied to Li2S‐based anode‐free cells to minimize the Te content in the system while extending the cell cycle life. Coating TeNW onto the separator greatly enhances Te utilization and demonstrates a significant cycle life improvement (38% retention over 300 cycles) with only 4 wt% TeNW content relative to the active material. The versatility of TeNW is further demonstrated by utilizing them with carbon nanotubes as the anode substrate. The exceptional performance of TeNW is attributed to the high‐surface‐area nanostructure and excellent conductive network, facilitating efficient electron transfer during cell cycling. These advantageous properties position TeNW as a promising material to enhance the cycle life of Li‐limited Li–S batteries.