Mixed-dimensional van der Waals heterojunction-enhanced Raman scattering

Li, Mingze; Wei, Yunjia; Fan, Xingce; Li, Guoqun; Qi, Hao; Qiu, Teng

doi:10.1007/s12274-021-3537-2

Cited by 20 publications

(20 citation statements)

References 45 publications

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“…45 Panels c and d of Figure 5 depict the intensity ratios between the b 2 mode at 612 cm −1 and the a 1 mode at 1362 cm −1 (I bd 2 /I ad 1 ) for the samples with and without an Al 2 O 3 coating layer, respectively. 46 One can see that the intensity ratio remains approximately unchanged during the experiment when the Al 2 O 3 coating layer is applied (Figure 5d). The result is in agreement with our prediction that the peak intensities of the a 1 and b 2 modes should increase and decrease in equal proportions when the electromagnetic mechanism plays the dominant role in SERS enhancement.…”

Section: T H Imentioning

confidence: 85%

“…It is clear that the SERS intensities of the recorded modes decreased significantly in the first 2 h and almost recovered to the initial intensities (pristine samples) after 72 h. These Raman modes can be divided into two categories: the totally symmetric vibration mode a 1 , which does not respond to the charge exchanges between plasmonic metals and the adsorbed molecules, and non-totally symmetric vibration mode b 2 , which is sensitive to charge transfer . Panels c and d of Figure depict the intensity ratios between the b 2 mode at 612 cm –1 and the a 1 mode at 1362 cm –1 ( I b 2 / I a 1 ) for the samples with and without an Al 2 O 3 coating layer, respectively . One can see that the intensity ratio remains approximately unchanged during the experiment when the Al 2 O 3 coating layer is applied (Figure d).…”

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confidence: 96%

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Electromagnetic Mechanisms or Chemical Mechanisms? Role of Interfacial Charge Transfer in the Plasmonic Metal/Semiconductor Heterojunction

Tang

Fan

Yao

et al. 2022

J. Phys. Chem. Lett.

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The plasmonic metal/semiconductor heterojunction provides a unique paradigm for manipulating light to improve the efficiency of plasmonic materials. Previous studies suggest that the improvement originates from the enhanced carrier exchanges between the plasmonic component of the heterojunction and molecules. This viewpoint, known as the chemical mechanism, is reasonable but insufficient, because the construction of the heterojunction will lead to a charge redistribution in the plasmonic component and cause changes in its physical characteristics. Herein, we will try to clarify that these changes are decisive factors in specific applications by investigating the surface-enhanced Raman scattering (SERS) behavior of a typical Ag/TiO 2 heterojunction. We observed significant changes in SERS spectra by modulating the band alignment of the heterojunction in a loop. Identical trends in SERS spectra were observed despite the fact that the charge transfer from the heterojunction to molecules was blocked, suggesting that the major SERS enhancement originates from electromagnetic mechanisms rather than chemical ones.

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Section: T H Imentioning

confidence: 85%

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confidence: 96%

Electromagnetic Mechanisms or Chemical Mechanisms? Role of Interfacial Charge Transfer in the Plasmonic Metal/Semiconductor Heterojunction

Tang

Fan

Yao

et al. 2022

J. Phys. Chem. Lett.

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“…Therefore, it is of great significance to use vdWHs to improve the sensitivity of SPR sensors and to design new sensors [ 16 , 17 , 18 ]. In fact, recent reports on sensitive SPR detection technology based on vdWHs have confirmed this assumption [ 19 , 20 ]. Therefore, we introduced vdWHs to increase detection sensitivity, which is expected to broaden the application of SPR sensors in quantitative analysis.…”

Section: Introductionmentioning

confidence: 89%

Design and Simulation of a Ratiometric SPR Sensor Based on a 2D van der Waals Heterojunction for Refractive Index Measurement

Zhou

Zhang

et al. 2023

Nanomaterials

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Surface plasmon resonance (SPR) sensors have been widely applied in many fields because of their advantages of working in real time and high sensitivity. However, because the spectrum of an SPR sensor is easily affected by the smoothness of the metal surface, this type of sensor has obvious disadvantages in the application of quantitative detection. We designed an SPR refractive index sensor for molecular detection that has the advantage of quantifiability. A ratio spectral quantitative analysis method was established based on the two coherent dips of the SPR spectrum formed by the strong coupling effect between the surface plasmon polaritons and the excitons of the J-aggregate molecule 5,6-dichloro-2–[3–[5,6-dichloro-1-ethyl-3–(4-sulfobutyl)–2-benzimidazoline subunit] propenyl]–3-ethyl-1–(4-sulfobutyl) benzimidazole hydroxide inner salt (TDBC). The introduced MoS2/graphene van der Waals heterojunction produced an effective charge transfer to the Ag film, resulting in significant electric field enhancement at the sensing interface and further improving the detection sensitivity of the sensor. The simulation results showed that for 43 nm Ag film, for example, the ratiometric SPR sensor with the Ag film structure can obtain 16.12 RIU-1 sensing sensitivity, applied to the detection of gas molecules, while the SPR sensor with single-layer graphene and three layers of MoS2 heterostructures can obtain 50.68 RIU-1 sensing sensitivity. The addition of van der Waals heterostructures can significantly improve sensing performance by 215%.

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“…The SERS activity of noble-metal-free materials is mainly derived from the charge transfer (CT) between the material and the adsorbed molecule, namely the chemical mechanism (CM). , Compared with noble metal materials, noble-metal-free materials possess more plentiful physical and chemical properties, providing enormous possibilities for the optimization of SERS performances. In recent years, researchers have prepared a series of novel noble-metal-free SERS materials with excellent performances through optimizing the morphology, , stoichiometric ratio, , crystallinity, , and crystal orientation of non-noble metal materials, such as metal oxides, − transition metal dichalcogenides, , metal organic frameworks, , organic semiconductors, , etc. However, these enhancement strategies tend to focus on regulating the physical and chemical properties of noble-metal-free materials, while ignoring the improvement of SERS performances by molecular enrichment.…”

Section: Introductionmentioning

confidence: 99%

Flexible Two-Dimensional Vanadium Carbide MXene-Based Membranes with Ultra-Rapid Molecular Enrichment for Surface-Enhanced Raman Scattering

Lan

Fan

et al. 2022

ACS Appl. Mater. Interfaces

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MXene materials have attracted broad interest in surface-enhanced Raman scattering (SERS) applications by virtue of their abundant surface terminations and excellent photoelectric properties. Herein, we propose to design highly sensitive MXene-based SERS membranes by integrating a 2D downsizing strategy with molecular enrichment approaches. Two types of 2D vanadium carbide (V 4 C 3 and V 2 C) MXenes are demonstrated for ultrasensitive SERS sensing, and corresponding SERS mechanisms including the effect of 2D vanadium carbide thickness on their electron density states and interfacial photoinduced charge transfer resonance were discussed. A 2D downsizing strategy authorizes nonplasmonic SERS detection with a sensitivity of 1 × 10 −7 M. Moreover, the performance can be further upgraded by vacuum-assisted filtration, which enables an ultrarapid molecular enrichment (within 2 min), ultrahigh molecular removal rate (over 95%), and improved sensitivity (5 × 10 −9 M). This work may shed light on the MXene-based materials as an innovative platform for nonplasmonic SERS detection.

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Mixed-dimensional van der Waals heterojunction-enhanced Raman scattering

Cited by 20 publications

References 45 publications

Electromagnetic Mechanisms or Chemical Mechanisms? Role of Interfacial Charge Transfer in the Plasmonic Metal/Semiconductor Heterojunction

Electromagnetic Mechanisms or Chemical Mechanisms? Role of Interfacial Charge Transfer in the Plasmonic Metal/Semiconductor Heterojunction

Design and Simulation of a Ratiometric SPR Sensor Based on a 2D van der Waals Heterojunction for Refractive Index Measurement

Flexible Two-Dimensional Vanadium Carbide MXene-Based Membranes with Ultra-Rapid Molecular Enrichment for Surface-Enhanced Raman Scattering

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