Coupled 2D Semiconductor–Molecular Excitons with Enhanced Raman Scattering

Muccianti, Christine; Zachritz, Sara L.; Garlant, Angel; Eads, Calley N.; Badada, Bekele; Alfrey, Adam; Köehler, Michael; Mandrus, David; Binder, R.; LeRoy, Brian J.; Monti, Oliver L. A.; Schaibley, John

doi:10.1021/acs.jpcc.0c06544

Cited by 6 publications

(5 citation statements)

References 56 publications

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“…Because of the quantum confinement and surface effects, low-dimensional materials may exhibit extraordinary electronic, optical, thermal, and chemical properties and have great potential in the application of electronics, optoelectronics, and spintronics. − Since the discovery of graphene in 2004, the mechanical exfoliation technique has been widely applied to a variety of van der Waals (vdW) materials to obtain high-quality two-dimensional (2D) materials, for example, hexagonal boron nitride, transition metal dichalcogenides, and black phosphorus. Meanwhile, the preparation of one-dimensional (1D) materials is usually limited to the bottom-up approach, including techniques such as physical vapor deposition, , chemical vapor deposition, , and molecular beam epitaxy. , The mechanical exfoliation method is, in principle, applicable to vdW materials consisting of 1D chains for the preparation of 1D materials, but few reports have addressed this issue to date …”

Section: Introductionmentioning

confidence: 99%

Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

et al. 2021

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Mechanical exfoliation is of great potential in the preparation of two-dimensional (2D) materials such as graphene and transition metal dichalcogenides, offering new opportunities for exploring extraordinary electronic, optic, optoelectronic, and spintronic properties of low-dimensional materials. However, the extension of the exfoliation method from 2D van der Waals materials to one-dimensional (1D) materials has rarely been reported. Here, we show that the 1D α-Bi 4 Br 4 nanobelts can be prepared by direct exfoliation of single crystals, as characterized by optical microscopy, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and Raman spectroscopy. Electrical transportation measurements indicate that the nanobelts maintain the intrinsic semiconducting properties of the bulk. Remarkably, the nanobelts can bear a very high current density up to 10 6 Acm −2 at room temperature, much higher than that of most semiconducting nanowires reported so far and comparable with that of Cu or Ag. This behavior is attributed to their 1D topological edge states. Our work demonstrates that mechanical exfoliation is an effective way to prepare high-quality α-Bi 4 Br 4 nanobelts for the investigation of fundamental topological physics and the development of high-performance electronic devices.

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Section: Introductionmentioning

confidence: 99%

Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

et al. 2021

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“…For both PBI‐R1 and PBI‐R2, a large apparent increase PL intensity can be seen at 2.1 eV, seen more clearly at higher incident intensities (Figure S3a, Supporting Information) at the expected position of the MoS 2 B exciton. This feature originates from the 0→1 transition of the PBI molecule at 2.12 eV [ 23 ] which was confirmed by measuring free PBI on the surrounding substrate which gave the same peak shape and position (Figure S3a, Supporting Information).…”

Section: Resultsmentioning

confidence: 61%

“…The modes at 1301, 1383, and 1587 cm −1 are assigned to the ring‐breathing, Kekule and asymmetric modes of the polyaromatic perylene core [ 22 ] and emerge due to resonant exciton‐phonon coupling and CT between the perylene molecules and the TMD. [ 14,23 ] The spectrum of PBI‐R1 also shows additional modes at 235 and 290 cm −1 , highlighted in red in Figure 1d, which are assigned to the MoS 2 LA(M) mode and a PBI A g mode originating from the perylene core, [ 24 ] respectively. The presence of the LA(M) mode indicates disorder‐induced scattering [ 25 ] where perylene molecules are expected to hybridize with MoS 2 layers at this symmetry point.…”

Section: Resultsmentioning

confidence: 99%

“…The 290 cm −1 A g perylene mode observed in Figure 1d has a reduced intensity in PBI‐R1, as to be expected for this Raman enhancement mechanism, away from resonance with the perylene absorption. [ 23 ] PBI‐R2 shows the presence of this mode under these conditions, indicating higher levels of intermolecular interaction (Figure S1, Supporting Information). [ 35 ] These observations demonstrate the presence of two distinct orientations of the PBI molecules on the MoS 2 surface in the PBI‐R1 and PBI‐R2 regions.…”

Section: Resultsmentioning

confidence: 99%

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Orientation Dependent Interlayer Coupling in Organic–Inorganic Heterostructures

Bartlam,

Saigal,

Heiserer

et al. 2024

Adv Funct Materials

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Organic–inorganic 2D heterostructures combine the high optical absorption of organic molecules with exciton‐dominated optical properties in layered transition metal dichalcogenides (TMDs) such as MoS2. Critical to the interaction and the optical response in such hybrid systems is the electronic band alignment at the interface between the two species. Here, the coupling of monolayers of perylene derivatives is investigated with bilayer MoS2. In particular, variation in the perylene orientation on the MoS2 surface is identified using Raman spectroscopy and scanning probe microscopy. Low‐temperature optical spectroscopy reveals orientation‐dependent interlayer exciton formation. Furthermore, power‐dependent photoluminescence measurements provide insight into the modified interlayer charge transfer in these heterostructures. A saturation of interlayer states is found under high excitation power when the perylene molecules are in a perpendicular orientation to the surface that leads to electron accumulation in the MoS2, whereas parallel alignment of the perylene molecules leads to enhanced populations of organic–inorganic interlayer excitons. This work provides insights into the optimization of organic–inorganic heterostructures, with particular relevance to applications for optoelectronic and excitonic devices.

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“…The main signal amplifiers developed for SERS tags are based on inorganic metal nanoparticles. Nevertheless, more recently, alternative materials such as graphene [ 84 ] and semi-conducting transition metal dichalcogenide substrates [ 85 , 86 ] have been explored and show promising results as highly active SERS substrates.…”

Section: The Building Blocks Of Sers-tagsmentioning

confidence: 99%

Microfluidic SERS devices: brightening the future of bioanalysis

et al. 2022

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A new avenue has opened up for applications of surface-enhanced Raman spectroscopy (SERS) in the biomedical field, mainly due to the striking advantages offered by SERS tags. SERS tags provide indirect identification of analytes with rich and highly specific spectral fingerprint information, high sensitivity, and outstanding multiplexing potential, making them very useful in in vitro and in vivo assays. The recent and innovative advances in nanomaterial science, novel Raman reporters, and emerging bioconjugation protocols have helped develop ultra-bright SERS tags as powerful tools for multiplex SERS-based detection and diagnosis applications. Nevertheless, to translate SERS platforms to real-world problems, some challenges, especially for clinical applications, must be addressed. This review presents the current understanding of the factors influencing the quality of SERS tags and the strategies commonly employed to improve not only spectral quality but the specificity and reproducibility of the interaction of the analyte with the target ligand. It further explores some of the most common approaches which have emerged for coupling SERS with microfluidic technologies, for biomedical applications. The importance of understanding microfluidic production and characterisation to yield excellent device quality while ensuring high throughput production are emphasised and explored, after which, the challenges and approaches developed to fulfil the potential that SERS-based microfluidics have to offer are described.

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Coupled 2D Semiconductor–Molecular Excitons with Enhanced Raman Scattering

Cited by 6 publications

References 56 publications

Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

Orientation Dependent Interlayer Coupling in Organic–Inorganic Heterostructures

Microfluidic SERS devices: brightening the future of bioanalysis

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Coupled 2D Semiconductor–Molecular Excitons with Enhanced Raman Scattering

Cited by 6 publications

References 56 publications

Ultralong Single-Crystal α-Bi4Br4 Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

Ultralong Single-Crystal α-Bi4Br4 Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

Orientation Dependent Interlayer Coupling in Organic–Inorganic Heterostructures

Microfluidic SERS devices: brightening the future of bioanalysis

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Product

Resources

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Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation

Ultralong Single-Crystal α-Bi₄Br₄ Nanobelts with a High Current-Carrying Capacity by Mechanical Exfoliation