Surface evolution of Janus Cu-Ag nanoparticles: Influence of atom arrangements and interface structures

2020 ◽  
Vol 13 (07) ◽  
pp. 2050037
Author(s):  
Mengfan Liang ◽  
Ziyi Xiong ◽  
Yongmao Hu ◽  
Yingli Liu ◽  
Tao Shen ◽  
...  

In this paper, the effect of the atom ratio and interface structure on the surface evolution of Janus Cu–Ag Nanoparticles (NPs) were studied by molecular dynamics (MDs) simulation during sintering process. The results show that Cu/Ag alloys tend to form the Cu-core@Ag-shell NPs with stable configuration in the case of excessive Ag. However, the different arrangements of atoms and interface lead to Janus Cu–Ag NPs exhibiting unique coalescence during the contact stage of sintering process, and the interface with Cu/Ag two-type atoms is more likely to diffuse. Moreover, the systems gradually change from separate NPs to a uniform Cu/Ag alloy as the temperature rising, meanwhile the shrinkage ratio of the Janus Cu–Ag NPs is stable at 80%.

Author(s):  
M.J. Witcomb ◽  
U. Dahmen ◽  
K.H. Westmacott

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.


2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Shiqiang Zhou ◽  
Mingpeng Chen ◽  
Qingjie Lu ◽  
Yumin Zhang ◽  
Jin Zhang ◽  
...  

AbstractFormaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity.


2021 ◽  
Author(s):  
Biraj Shougaijam ◽  
Salam Surjit Singh

Abstract In this work, vertically aligned TiO 2 -Nanowires (TiO 2 -NWs) and Ag Nanoparticles assisted TiO 2 Nanowires (TAT-NWs) were deposited on glass and flexible PET substrates using the Glancing Angle Deposition (GLAD) technique. The morphology and structural analysis of the samples manifest the successful deposition of vertically aligned TiO 2 -NWs and TAT-NWs. The HR-TEM image of TiO 2 -NWs shows the polycrystalline nature. Further, the XRD result confirms the polycrystalline nature of both the TiO 2 -NWs and TAT-NWs samples. Besides, the HR-TEM image confirms the presence of small crystal grains of Ag Nanoparticles (Ag-NPs) at the mid of the annealed TAT-NWs. It is evident from the Selective Area Electron Diffraction (SAED) analysis of the TiO 2 -NWs and annealed TAT-NWs that the crystallinity of TiO 2 present in the annealed TAT-NWs improves after annealing. The absorption spectrum analysis of TAT-NWs deposited on glass substrate shows enhance absorption peak in the visible region with a maximum peak at ~463 nm wavelength compare to the TiO 2 -NWs, which may be attributed to the Surface Plasmon Resonance (SPR) effect of Ag-NPs. Further, it is interesting to observe that the TAT-NWs deposited on PET substrate show further absorption enhancement in the UV and visible region. In addition, the Photoluminescence analysis reveals that the bandgap of the TiO 2 -NWs is ~3.12 eV, which supports the bandgap extracted from the Tauc plot. Therefore, the proposed method of fabricating TAT-NWs on glass and flexible ITO coated PET substrate using the GLAD technique may be applicable for developing novel photoanode for Dye-sensitized Solar Cells (DSSCs) and other optoelectronic applications.


2016 ◽  
Vol 847 ◽  
pp. 194-199
Author(s):  
Jin Dan Zhang ◽  
Mei Yu ◽  
Jian Hua Liu ◽  
Song Mei Li ◽  
Yan Bing Meng

Under the photoirradiation, DNA works as both template and reducing agent to drive the formation of metallic nanomaterials. In this study the plasmid DNA with different base pairs was applied as biotemplate to synthesize Ag nanoparticles (NPs) by using photoirradiation approach. The evolution of DNA dimension changed during the synthesis process, and their effect on the morphology of the synthesized Ag NPs was studied by UV-Vis spectra, FT-IR spectra, Raman spectra, AFM, and TEM. It is found that the plasmid DNA shrinked twice during the synthesis, the first time happened when the Ag (I) cations neutralized the negative charge along the DNA chain, and the second time happened when plasmid DNA reduced Ag (I) induced by the ultraviolet C (254 nm) irradiation. The size of the synthesized Ag NPs showed approximately linear relationship with the dimension of plasmid DNA scaffolds under this photo-induce condition. The compaction degree of the plasmid DNA during the Ag formation was shown by the slope of the linear relationship.


2019 ◽  
Vol 55 (74) ◽  
pp. 11045-11048 ◽  
Author(s):  
Tingting Zhou ◽  
Ziyu Qin ◽  
Xiaoxia Wang ◽  
Congyi Wu ◽  
Xing Tang ◽  
...  

Ag NPs are encapsulated into ZIF-71 serving as an adjustable molecular sieving layer to hydrogen and acetone.


RSC Advances ◽  
2015 ◽  
Vol 5 (50) ◽  
pp. 40135-40140
Author(s):  
Jianwei Jiang ◽  
In Seok Hong ◽  
Habeebullah Thajudeen ◽  
Ying Lu ◽  
Sang-Ho Kim ◽  
...  

The dispersion stability of Ag NPs could be greatly enhanced by mixing n-alkylcarboxylic acid surfactants with two different chain lengths.


2013 ◽  
Vol 760-762 ◽  
pp. 801-805 ◽  
Author(s):  
Chao Yue Deng ◽  
Gu Ling Zhang ◽  
Bin Zou ◽  
Hong Long Shi ◽  
Yu Jie Liang ◽  
...  

We used a simple low-temperature hydrothermal approach to synthesize Ag nanoparticles (NPs) and demonstrated their efficiency as organic molecule detectors in surface enhanced Raman Scattering (SERS). Using finite difference time domain simulation, we described an investigation on the distribution of electric fields amplitude of the neighboring Ag NPs. The enhanced electric field is confined at the interparticle gaps and the enhancement factor can be further increased with reducing the spacing between the NPs. The theoretical simulation demonstrated good consistency with the experimental measurement results, which predicts an electric fields amplitude enhancement of 115 at the center of NPs gap and an electromagnetic SERS enhancement of 108. The evidence of clear correlations between SERS enhancement and morphology distribution offer a route to develop more effective SERS substrates.


2015 ◽  
Vol 3 (6) ◽  
pp. 1319-1324 ◽  
Author(s):  
Sihui Li ◽  
Wenhua Li ◽  
Qian Liu ◽  
Hedi Wei ◽  
Enquan Jin ◽  
...  

The efficiency of PSCs has been greatly improved by spin-coating monodisperse Ag NPs on ITO substrates.


2017 ◽  
Vol 897 ◽  
pp. 634-637
Author(s):  
Yi Wei ◽  
Ahmed Fadil ◽  
Hai Yan Ou

Silver (Ag) nanoparticles (NPs) were deposited on the surface of bulk Nitrogen-Boron co-doped 6H silicon carbide (SiC), and the Ag NPs were observed to induce localized surface plasmons (LSP) resonances on the SiC substrate, which was expected to improve the internal quantum efficiency (IQE) of the emissions of the donor-acceptor pairs of the SiC substrate. Room-temperature measurements of photoluminescence (PL), transmittance and time-resolved photoluminescence (TRPL) were applied to characterize the LSP resonances. Through the finite-difference time-domain (FDTD) simulation of the LSP resonance of an Ag nanoparticle on the SiC substrate, it is predicted that when the diameter of the cross section on the xy plane of the Ag nanoparticle is greater than 225 nm, the LSP starts to enhance the PL intensity. With implementation of a 3rd order exponential decay fitting model to the TRPL results, it is found that the average minority carrier lifetime of the SiC substrate decreased.


RSC Advances ◽  
2015 ◽  
Vol 5 (74) ◽  
pp. 59895-59902 ◽  
Author(s):  
Hyun-Young Kim ◽  
Jung Sang Suh

We developed a panchromatic quasi-monolayer of Ag NPs and applied this technique to fabricate DSSCs.


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