Potential modulations in flatland: near-infrared sensitization of MoS2 phototransistors by a solvatochromic dye directly tethered to sulfur vacancies

Dalgleish, Simon; Reissig, Louisa; Shuku, Yoshiaki; Ligorio, Giovanni; Awaga, Kunio; List‐Kratochvil, Emil J. W.

doi:10.1038/s41598-019-53186-2

Cited by 14 publications

(11 citation statements)

References 32 publications

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“…Hence, without surprise, TMDs have attracted significant scientific interest as promising materials in electronic, optical, and catalytic applications, such as in photovoltaics, lithium-ion batteries, photo/electrocatalysis, transistors, sensors, and memory devices. [21][22][23][24][25][26][27][28] Generally, there are two basic approaches for manufacturing TMD nanosheets, namely, bottom-up and top-down. The bottomup approach refers to synthetic procedures in which simple units chemically assemble into larger structures.…”

Section: Doi: 101002/aesr202200097mentioning

confidence: 99%

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Stangel

Nikoli

Tagmatarchis

2022

Adv Energy and Sustain Res

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Transition metal dichalcogenides (TMDs) are materials with the generalized formula MX 2 , where M refers to a transition metal from groups 4-7 of the periodic table and X is a chalcogen atom such as S, Se, or Te. [1] The metal cation is bonded to four chalcogenide anions in a honeycomb lattice. This structure forms a three-atom thick layer, where the metals are sandwiched between the chalcogens. Markedly, the chalcogens do not have high reactivity due to chemical saturation by bonding to the transition metal atoms. These three-atom thick layers are held together with multiple van der Waals forces. [2] However, they can be easily exfoliated by splitting these weak interlayer interactions upon use of a variety of techniques, forming 2D nanosheets with extraordinary physical and chemical properties. In addition, TMDs exist in different lattice structures, which influence the materials' electronic character. Monolayer TMDs have a trigonal prismatic phase (2H phase), that belongs to the D 3h symmetry group and corresponds to a trigonal prismatic coordination for the metal atoms, or an octahedral phase (1T phase), that belongs to the D 3d symmetry group and corresponds to an octahedral coordination of the metal atoms. [3,4] The 1T phase is metastable and tends to convert to the thermodynamically stable 2H phase at room temperature via intralayer atomic gliding. [5] The realization of TMD monolayers leads to the confinement of charge carriers in 2D. Thus, due to quantum confinement effects, the transition from indirect bandgap at bulk TMDs, to direct bandgap at few layers and monolayers, occurs, [6] leading to enhanced photoluminescence. [7] Consequently, this is a straightforward approach for tuning the material's photophysical properties. In addition to the aforementioned strategy for obtaining and manipulating the electronic characteristics of TMDs, tuning the materials' properties can be further achieved through doping methods [8] or heterojunctions creation. [9][10][11] However, due to their atomically thin layers' nature, it becomes impossible to dope TMDs using common techniques that are widely used in semiconductors. [12] In contrast, chemical exfoliation and processing have the advantage of simultaneous modification of the electronic nature of TMDs [13] and in parallel offer the benefit of enhancing dispersibility, allowing surface modification. [14,15] Thus, another way to manipulate the electronic properties of TMDs is by edge or surface functionalization, especially upon incorporation of photoactive molecular species. The latter is a process that has recently emerged for TMDs and considering the advancement already brought in graphene, by the development of numerous functional graphene-based hybrid materials performing in energy conversion schemes under illumination, it certainly deserves further boost. [16][17][18][19] Moreover, among various approaches and

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Section: Doi: 101002/aesr202200097mentioning

confidence: 99%

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Stangel

Nikoli

Tagmatarchis

2022

Adv Energy and Sustain Res

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Section: Introductionmentioning

confidence: 99%

“…Ultrafast (<150 fs) CT has been observed in such configurations, and these were employed in hybrid photodetectors, where the absorption of light in the organic layer was shown to enhance and spectrally extend the photoresponse. [7][8][9][10][11] Despite the above mentioned strong light-matter interaction, ML-TMDCs generally suffer from comparably low photoluminescence (PL) yield at room temperature. Besides meticulous reduction of structural defects in the monolayer, the combination with organic molecules can also provide a solution here.…”

Section: Introductionmentioning

confidence: 99%

Type‐I Energy Level Alignment at the PTCDA—Monolayer MoS₂ Interface Promotes Resonance Energy Transfer and Luminescence Enhancement

et al. 2021

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Van der Waals heterostructures consisting of 2D semiconductors and conjugated molecules are of increasing interest because of the prospect of a synergistic enhancement of (opto)electronic properties. In particular, perylenetetracarboxylic dianhydride (PTCDA) on monolayer (ML)‐MoS2 has been identified as promising candidate and a staggered type‐II energy level alignment and excited state interfacial charge transfer have been proposed. In contrast, it is here found with inverse and direct angle resolved photoelectron spectroscopy that PTCDA/ML‐MoS2 supported by insulating sapphire exhibits a straddling type‐I level alignment, with PTCDA having the wider energy gap. Photoluminescence (PL) and sub‐picosecond transient absorption measurements reveal that resonance energy transfer, i.e., electron–hole pair (exciton) transfer, from PTCDA to ML‐MoS2 occurs on a sub‐picosecond time scale. This gives rise to an enhanced PL yield from ML‐MoS2 in the heterostructure and an according overall modulation of the photoresponse. These results underpin the importance of a precise knowledge of the interfacial electronic structure in order to understand excited state dynamics and to devise reliable design strategies for optimized optoelectronic functionality in van der Waals heterostructures.

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“…[4,5] Resulting single layer areas are mostly limited by the parent crystal areas, approaching a near unity exfoliation yield, which allows for large-scale single layers in action. [3,[9][10][11] The interaction is noncovalent in nature and is highly dependent on the condition of the gold surface, where even slight contamination diminishes the exfoliation yield. [5] Recently, interfacial strain has been recognized as additional critical factor for the success of gold-mediated exfoliation, promoting the exfoliation of a single layer by disrupting the interlayer stacking.…”

mentioning

confidence: 99%

Low Temperature Heating of Silver‐Mediated Exfoliation of MoS₂

Heyl

Grützmacher

Rühl

et al. 2022

Adv Materials Inter

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The need for high‐quality large‐scale monolayers of layered materials pushes the development of scalable gold‐mediated exfoliations. Gold proves to be a suitable adhesive for exfoliation of several 2D materials. However, the extension to other noble metals remains underwhelming as gold outperforms all previously studied metals by a large margin. This is attributed to compromised stability against oxidation and surface contamination of less noble metals, leading to nonideal interfaces for exfoliation. The closest competitor to gold is silver, where gold still leads by a factor 100 regarding exfoliated layer size. In this work, a silver‐mediated exfoliation process performing on par with gold is presented. The combination of freshly cleaved silver surfaces with a low‐temperature annealing is found to be crucial. The exfoliation yield shows a dependence with annealing temperature, leading to loss in exfoliation performance for higher temperature. Raman studies indicate inhomogeneous strain for the MoS2/Ag interface at these temperatures, which hints at the competing factors of thermal activation versus oxidation of silver. Finally, a transfer process is implemented to promote silver to a fully functional exfoliation substrate. Ultimately, heating up exfoliations tips the strict balance between interfacial interactions and surface contaminations toward robust high monolayer yield exfoliation as demonstrated for silver.

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Potential modulations in flatland: near-infrared sensitization of MoS2 phototransistors by a solvatochromic dye directly tethered to sulfur vacancies

Cited by 14 publications

References 32 publications

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Type‐I Energy Level Alignment at the PTCDA—Monolayer MoS₂ Interface Promotes Resonance Energy Transfer and Luminescence Enhancement

Low Temperature Heating of Silver‐Mediated Exfoliation of MoS₂

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Potential modulations in flatland: near-infrared sensitization of MoS2 phototransistors by a solvatochromic dye directly tethered to sulfur vacancies

Cited by 14 publications

References 32 publications

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Transition Metal Dichalcogenides Interfacing Photoactive Molecular Components for Managing Energy Conversion Processes

Type‐I Energy Level Alignment at the PTCDA—Monolayer MoS2 Interface Promotes Resonance Energy Transfer and Luminescence Enhancement

Low Temperature Heating of Silver‐Mediated Exfoliation of MoS2

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Type‐I Energy Level Alignment at the PTCDA—Monolayer MoS₂ Interface Promotes Resonance Energy Transfer and Luminescence Enhancement

Low Temperature Heating of Silver‐Mediated Exfoliation of MoS₂