Engineering metal oxide semiconductor nanostructures for enhanced charge transfer: fundamentals and emerging SERS applications

Samriti,; Rajput, Vishal; Gupta, Raju Kumar; Prakash, Jai

doi:10.1039/d1tc04886d

Cited by 108 publications

(67 citation statements)

References 94 publications

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“…In semiconductors, electrons could make a jump from the VB to the CB but not with the same ease as they do in conductors, since the gap between the VB and CB is larger in the case of semiconductors. 12 Spectrophotometric techniques are used to find the energy bandgap in semiconductors. The energy bandgap was assessed from the intercept of the linear portion of the individual curve for various annealing temperatures through the h ν on the x- axis.…”

Section: Introductionmentioning

confidence: 99%

“…The variation of (α h ν) 2 with h ν is plotted for a metal oxide nanoparticle annealed at different temperatures and different doping concentrations. In semiconductors, electrons could make a jump from the VB to the CB but not with the same ease as they do in conductors, since the gap between the VB and CB is larger in the case of semiconductors . Spectrophotometric techniques are used to find the energy bandgap in semiconductors.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Sulfur Doping and Temperature on the Energy Bandgap of ZnO Nanoparticles and Their Antibacterial Activities

Aga

Efa²,

Beyene

2022

ACS Omega

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Metal oxide nanoparticles (MO-NPs) are presently an area of intense scientific research, attributable to their wide variety of potential applications in biomedical, optical, and electronic fields. MO-NPs such as zinc oxide nanoparticles (ZnO-NPs) and others have a very high surface-area-to-volume ratio and are excellent catalysts. MO-NPs could also cause unexpected effects in living cells because their sizes are similar to important biological molecules, or parts of them, or because they could pass through barriers that block the passage of larger particles. However, undoped MO-NPs like ZnO-NPs are chemically pure, have a higher optical bandgap energy, exhibit electron–hole recombination, lack visible light absorption, and have poor antibacterial activities. To overcome these drawbacks and further outspread the use of ZnO-NPs in nanomedicine, doping seems to represent a promising solution. In this paper, the effects of temperature and sulfur doping concentration on the bandgap energy of ZnO nanoparticles are investigated. Characterizations of the synthesized ZnO-NPs using zinc acetate dihydrate as a precursor by a sol–gel method were done by using X-ray diffraction, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. A comparative study was carried out to investigate the antibacterial activity of ZnO nanoparticles prepared at different temperatures and different concentrations of sulfur-doped ZnO nanoparticles against Staphylococcus aureus bacteria. Experimental results showed that the bandgap energy decreased from 3.34 to 3.27 eV and from 3.06 to 2.98 eV with increasing temperature and doping concentration. The antibacterial activity of doped ZnO nanoparticles was also tested and was found to be much better than that of bare ZnO nanoparticles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Sulfur Doping and Temperature on the Energy Bandgap of ZnO Nanoparticles and Their Antibacterial Activities

Aga

Efa²,

Beyene

2022

ACS Omega

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“…Surface-enhanced Raman scattering (SERS) can conspicuously enhance the signal intensity of Raman scattering when the analyte is adsorbed onto a SERS-active substrate, which has been widely researched in the fields of food analysis, biomedicine, and analytical chemistry. , The giant enhancement in sensitivity originates from the synergistic effect of the electromagnetic mechanism (EM) and chemical mechanism (CM). The EM is mainly attributed to the localized surface plasmon resonance (LSPR) and is generally agreed to be the largest part of the enhancement of the Raman signal, whereas the CM arises from the charge transfer between the SERS-active material and the adsorbed molecule and its enhancement degree is much lower than that of plasmon resonance . To obtain better chemical enhancement, 2D materials, such as graphene oxide (GO), have been used to combine with noble metals as the SERS substrate.…”

Section: Introductionmentioning

confidence: 99%

Ag Nanoparticle-Decorated Graphene Oxide Coatings on the Inner Walls of Optofluidic Capillaries for Real-Time Trace SERS Detection

Han

Fang

Sun

et al. 2022

ACS Appl. Nano Mater.

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Surface-enhanced Raman scattering (SERS) is a rapid and nondestructive spectroscopic method for trace detection. The enhancement based on both electromagnetic and chemical mechanism requires the molecules to be in close contact with the SERS-active material. Therefore, it is difficult to detect trace amounts of molecules in liquid directly. In this paper, graphene oxide (GO) and Ag nanoparticles (AgNPs) are uniformly modified on the inner wall of the capillary. GO can provide chemical enhancement by adsorbing the analyte onto its flat surface and producing efficient charge transfer resonance with the analyte. AgNPs can provide strong localized surface plasmon resonance for electromagnetic enhancement, while capillary can shorten the molecular enrichment time and provide long light–analyte interaction length. The synergism of GO, AgNPs, and capillary makes the optofluidic platform have the ability of ultrasensitive and real-time detection. The detection limit of Rhodamine 6G and thiram is as low as 10–12 and 10–10 M, respectively, and the enhancement factor is as high as 0.9 × 1010 and 108, which indicates that the SERS-active capillaries have great potentials in real-time ultratrace detection of water environment pollutants.

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“…Meanwhile, chemical SERS enhancement contributes up to the order of 10 5 attributed to the charge transfer (CT) between molecular orbitals of the SERS substrate and target species. 36,[42][43][44] For more details of SERS mechanisms and various dependent factors, the readers are advised to go through the literature. 22,40 Ion implantation/ irradiation has a unique tendency to produce such plasmonic NPs embedded within a few nanometers inside the surface of various materials with an opportunity to tailor their shape, size, and interparticle distance and modify the dielectric constant of the medium to enhance their SERS properties.…”

Section: Plasmonic and Sersmentioning

confidence: 99%

Ion beam nanoengineering of surfaces for molecular detection using surface enhanced Raman scattering

Prakash

Sharma

Wijesundera

et al. 2022

Mol. Syst. Des. Eng.

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Engineering metal oxide semiconductor nanostructures for enhanced charge transfer: fundamentals and emerging SERS applications

Abstract: Fundamentals of doping engineering strategies of metal oxide semiconductors and various charge transfer processes for emerging SERS applications are discussed.

Cited by 108 publications

References 94 publications

Effects of Sulfur Doping and Temperature on the Energy Bandgap of ZnO Nanoparticles and Their Antibacterial Activities

Effects of Sulfur Doping and Temperature on the Energy Bandgap of ZnO Nanoparticles and Their Antibacterial Activities

Ag Nanoparticle-Decorated Graphene Oxide Coatings on the Inner Walls of Optofluidic Capillaries for Real-Time Trace SERS Detection

Ion beam nanoengineering of surfaces for molecular detection using surface enhanced Raman scattering

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