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Author

De Zhang

Other affiliations: China Jiliang University
Bio: De Zhang is an academic researcher from Huazhong Agricultural University. The author has contributed to research in topics: Medicine & Chemistry. The author has an hindex of 8, co-authored 27 publications receiving 170 citations. Previous affiliations of De Zhang include China Jiliang University.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a flower-shaped silver nanoparticle was used as a substrate to investigate the SERS effect of pesticide molecules under different treatment conditions, and it was demonstrated that the optimum pH values for test conditions are in the range of 6.66-11.11 due to the auxiliary of H + ions and undestroyed complete functional groups of ethion.
Abstract: In this paper, the flower-shaped silver nanoparticle was used as substrate to investigate the SERS effect of pesticide molecules under different treatment conditions. Due to the variation of molecular structure and molecular interactions with pH value and solvent type, the combination mode of molecules and metal surface and electron transfer also changes, resulting in different SERS effects with a certain regularity. It was demonstrated that the optimum pH values for test conditions are in the range of 6.66–11.11 due to the auxiliary of H + ions and undestroyed complete functional groups of ethion. Meanwhile, the ethion in the acetone was the best in the three solvents (ultrapure water, absolute ethanol and acetone). Under optimal conditions, ethion can be detected with a minimum detectable concentration of 10 −10 M. The regression model obtained through principal component analysis (PCA) can be used for rapid and precise detection of the concentration of ethion, suggesting the importance of condition optimization for SERS test. Therefore, the solvent environment can be effectively improved to promote non-resonance enhancement of chemical bonding between adsorbate and metal substrate and resonance enhancement of light-induced charge transfer in molecular-metal system by excitation light. The solvent environment has significant effect on the SERS sensor from chemical enhancement.

48 citations

Journal ArticleDOI
TL;DR: A facile reduction method to modulate oxygen vacancy concentrations in oxide SERS substrates is provided and can be widely used in semiconductor oxide materials for its chemical enhancement capacity can be promoted by artificial oxygen vacancy.
Abstract: Recently, more and more attention has been given to a semiconductor oxide-based surface-enhanced Raman spectroscopy substrate for its great stability and biocompatibility. However, its poor SERS sensitivity limits the applications of semiconductor oxide SERS substrates. In this paper, we provide a facile reduction method to modulate oxygen vacancy concentrations in oxide SERS substrates. Using MoO2 as an example, the resonance coupling as well as charge transfer between the semiconductor oxide SERS substrate and the target molecules were promoted for the reason of artificial oxygen vacancy embodied in the Raman signals being improved. By using the TEM, SEM, and XPS measurements, we confirmed that we successfully prepared defective MoO2- x with a polycrystalline surface. MoO2- x modulated oxygen vacancy treated with 6 wt % Li shows a very high detection sensitivity of 10-8 M (4.79 ug/L) for R6G, and the intensity of the Raman signal was highly enhanced. Because of the existence of defective energy levels, resonance coupling, as well as charge transfer between semiconductor and molecules, was obviously promoted. More importantly, the method of modulating oxygen vacancy can be widely used in semiconductor oxide materials for its chemical enhancement capacity can be promoted by artificial oxygen vacancy.

40 citations

Journal ArticleDOI
TL;DR: This paper proposed a concept of "bridge" substances acting as an interconnect function role to achieve a binding model (object-binder-metal (OBM)) and developed a droplet concentration method to enhance Raman signals.

27 citations

Journal ArticleDOI
TL;DR: A dexterous and facile way for fabrication of CuO SERS-active substrates with low cost and high performance, quite promising in detection of chemically hazardous substances and pesticide residue is provided.
Abstract: Simple and traditional hydrothermal fabrication of a novel balsam pear-shaped CuO with high SERS enhancement is presented. XRD (X-ray diffraction), SEM (scanning electronic microscopy), TEM (transmission electron microscope), HRTEM (high-resolution transmission electron microscope), UV-Vis, and Raman are adopted to ensure that this balsam pear-shaped CuO with dense nanoparticle protuberance is successfully prepared. The LOD of this CuO SERS substrate is 4.79 μg L−1 with R6G as molecular probe. By using DFT (density functional theory) calculation and FDTD (finite difference time domainmethod) simulation, both EM (electromagnetic enhancement) and CM (chemical enhancement) mechanisms are investigated, and the results show that these two-enhancement mechanisms can coexist in this balsam pear-shaped CuO. Finally, the prepared substrate has been applied for the determination of trace levels of paraquat in solution , and results show that its LOD for paraquat is 275 μg L−1 (optimum Raman band: 1646 cm−1 Raman shift), which is better than the government standard in China. A dexterous and facile way for fabrication of CuO SERS-active substrates with low cost and high performance, quite promising in detection of chemically hazardous substances and pesticide residue is provided.

25 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a surface-enhanced Raman scattering (SERS) substrate with a high sensitivity and rapid response, which has been widely used in various fields, but it is still a challenge to prepare SERS substrates with...
Abstract: Surface-enhanced Raman scattering (SERS), owing to its high sensitivity and rapid response, has been widely used in various fields. However, it is still a challenge to prepare SERS substrates with ...

24 citations


Cited by
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Journal ArticleDOI
TL;DR: This comprehensive and critical review of coumarin-based small-molecule fluorescent chemosensors during the period of 2012-2018 may facilitate the development of more powerful fluorescent chemOSensors for broad and exciting applications in the future.
Abstract: Coumarins are a very large family of compounds containing the unique 2H-chromen-2-one motif, as it is known according to IUPAC nomenclature. Coumarin derivatives are widely found in nature, especially in plants and are constituents of several essential oils. Up to now, thousands of coumarin derivatives have been isolated from nature or produced by chemists. More recently, the coumarin platform has been widely adopted in the design of small-molecule fluorescent chemosensors because of its excellent biocompatibility, strong and stable fluorescence emission, and good structural flexibility. This scaffold has found wide applications in the development of fluorescent chemosensors in the fields of molecular recognition, molecular imaging, bioorganic chemistry, analytical chemistry, materials chemistry, as well as in the biology and medical science communities. This review focuses on the important progress of coumarin-based small-molecule fluorescent chemosensors during the period of 2012-2018. This comprehensive and critical review may facilitate the development of more powerful fluorescent chemosensors for broad and exciting applications in the future.

668 citations

Journal Article
TL;DR: In this paper, the authors performed experimental studies of droplet breakup in microfluidic T-junctions in a range of capillary numbers lying between 4×10−4 and 2 ×10−1 and for two viscosity ratios of the fluids forming the dispersed and continuous phases.
Abstract: We perform experimental studies of droplet breakup in microfluidic T-junctions in a range of capillary numbers lying between 4×10−4 and 2×10−1 and for two viscosity ratios of the fluids forming the dispersed and continuous phases. The present paper extends the range of capillary numbers explored by previous investigators by two orders of magnitude. We single out two different regimes of breakup. In a first regime, a gap exists between the droplet and the wall before breakup occurs. In this case, the breakup process agrees well with the analytical theory of Leshansky and Pismen [Phys. Fluids 21, 023303 (2009)]. In a second regime, droplets keep obstructing the T-junction before breakup. Using physical arguments, we introduce a critical droplet extension for describing the breakup process in this case.

122 citations

Journal ArticleDOI
Shan Cong1, Xiaohong Liu1, Yuxiao Jiang1, Wei Zhang1, Zhigang Zhao1 
TL;DR: This short review introduces the basic concepts underlying the SERS enhancements, the most recent semiconducting substrates that use novel manipulation strategies, and the extended applications of these versatile substrates.
Abstract: Surface enhanced Raman scattering (SERS) is a fingerprint spectral technique whose performance is highly dependent on the physicochemical properties of the substrate materials. In addition to the traditional plasmonic metal substrates that feature prominent electromagnetic enhancements, boosted SERS activities have been reported recently for various categories of non-metal materials, including graphene, MXenes, transition-metal chalcogens/oxides, and conjugated organic molecules. Although the structural compositions of these semiconducting substrates vary, chemical enhancements induced by interfacial charge transfer are often the major contributors to the overall SERS behavior, which is distinct from that of the traditional SERS based on plasmonic metals. Regarding charge-transfer-induced SERS enhancements, this short review introduces the basic concepts underlying the SERS enhancements, the most recent semiconducting substrates that use novel manipulation strategies, and the extended applications of these versatile substrates.

114 citations

Journal ArticleDOI
22 Apr 2021-Talanta
TL;DR: In this article, the authors provide an overview of recent advances and new trends in optical and electrochemical non-enzymatic (bio)sensors for the detection of pesticides by focusing on antibody, aptamer and molecularly imprinted polymer (MIP) recognition elements.

58 citations