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Murugan SS, Hur W, Son SE, Lee HB, Ha CH, Lee SJ, Cheon SH, Kim DH, Jeon SM, Choi DY, Venkatesan J, Seong GH. The therapeutic efficacy of silver loaded rhenium disulfide nanoparticles as a photothermal agent for cancer eradication. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 250:112831. [PMID: 38134574 DOI: 10.1016/j.jphotobiol.2023.112831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/26/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023]
Abstract
Cancer is a life-threatening disease when it is diagnosed at a late stage or treatment procedures fail. Inhibiting cancer cells in the tumor environment is a significant challenge for anticancer therapy. The photothermal effects of nanomaterials are being studied as a new cancer treatment. In this work, rhenium disulfide (ReS2) nanosheets were made by liquid exfoliation with gum arabic (GA) and coated with silver nanoparticles (AgNPs) to produce reactive oxygen species that destroy cancer cells. The synthesized AgNP-GA-ReS2 NPs were characterized using UV, DLS, SEM, TEM, and photothermal studies. According to the DLS findings, the NPs were about 216 nm in size and had a zeta potential of 76 mV. The TEM and SEM analyses revealed that the GA-ReS2 formed single-layered nanosheets on which the AgNPs were distributed. The photothermal effects of the AgNP-GA-ReS2 NPs at 50 μg/mL were tested with an 808 nm laser at 1.2 W cm-2, and they reached 55.8 °C after 5 min of laser irradiation. MBA-MB-231 cells were used to test the cytotoxicity of the newly designed AgNP-GA-ReS2 NPs with and without laser irradiation for 5 min. At 50 μg/mL, the AgNP-GA-ReS2 showed cytotoxicity, which was confirmed with calcein and EtBr staining. The DCFH-DA and flow cytometry analyses demonstrated that AgNP-GA-ReS2 nanosheets under NIR irradiation generated ROS with high anticancer activity, in addition to the photothermal effects.
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Affiliation(s)
- Sesha Subramanian Murugan
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea; Biomaterials Research Laboratory, Yenepoya Research Centre, Yenepoya Deemed to be University, Deralakatte, Mangaluru 575018, India
| | - Won Hur
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Seong Eun Son
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Han Been Lee
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Chang Hyeon Ha
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Su Jeong Lee
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Se Hwa Cheon
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Do Hyeon Kim
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Sung Min Jeon
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Da Young Choi
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea
| | - Jayachandran Venkatesan
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea; Biomaterials Research Laboratory, Yenepoya Research Centre, Yenepoya Deemed to be University, Deralakatte, Mangaluru 575018, India.
| | - Gi Hun Seong
- Department of Bionano Engineering, Center for Bionano Intelligence Education and Research, Hanyang University, Ansan 426-791, South Korea.
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Fadhel MM, Hamzah AE, Abd Aziz N, Dzulkefly Zan MS, Arsad N. Passively Q-switching an all polarization-maintaining erbium-doped fiber laser with a rhenium disulfide (ReS 2) saturable absorber. Heliyon 2023; 9:e20678. [PMID: 37860525 PMCID: PMC10582505 DOI: 10.1016/j.heliyon.2023.e20678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/04/2023] [Accepted: 10/04/2023] [Indexed: 10/21/2023] Open
Abstract
This study demonstrates a linearly polarized Er-doped fiber laser system featuring an all-polarization-maintaining (all-PM) architecture. Short pulses were generated by Q-switching operation based on drop-casting rhenium disulfide (ReS2) saturable absorber (SA) onto a fiber connector placed inside the laser cavity. The Q-switching operation of the laser was able to self-start at a low (23 mW) threshold power of the pump and without the need to use a polarization controller. The proposed laser was able to produce stable pulses with a center wavelength and 3-dB bandwidth of 1558.4 nm and 0.13 nm, respectively. The shortest pulse duration measured (2.8 μs) was achieved at a repetition rate of 37.6 kHz while the highest average output power and pulse energy were 2.2 mW and 76.5 nJ, respectively. Furthermore, as the cavity of the laser was designed to be all-PM the laser that it produced was linearly polarized and had a degree of polarization (DOP) at the level of 94.5 % and 40 dB polarization extinction ratio (PER). Therefore, the proposed laser is a suitable light source for optical applications in environments that are complex.
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Affiliation(s)
- Mahmoud Muhanad Fadhel
- Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Abdulwahhab Essa Hamzah
- Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Norazreen Abd Aziz
- Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Mohd Saiful Dzulkefly Zan
- Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Norhana Arsad
- Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
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Schiettecatte P, Singh S, Zhou P, Hens Z. The Dynamic Interaction of Surfactants with Colloidal Molybdenum Disulfide Nanosheets Calls for Thermodynamic Stabilization by Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:6568-6579. [PMID: 37095622 DOI: 10.1021/acs.langmuir.3c00546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Top-down liquid-phase exfoliation (LPE) and bottom-up hot-injection synthesis are scalable methods to produce colloids of two-dimensional (2D) van der Waals (vdW) solids. Generally thought off as two entirely different fields, we show that similar stabilization mechanisms apply to colloids of molybdenum disulfide (MoS2) produced by both methods. By screening the colloidal stability of MoS2 produced in a hot-injection synthesis in a wide range of solvents, we observe that colloidal stability can be understood based on solution thermodynamics, wherein matching the solubility parameter of solvent and nanomaterial maximizes colloidal stability. Identical to MoS2 produced through LPE, optimal solvents to disperse MoS2 produced from the bottom-up have similar solubility parameters of ≈22 MPa1/2 and include aromatic solvents with polar functionalities, such as o-dichlorobenzene, and polar aprotic solvents, such as N,N-dimethylformamide. We further complemented our findings by nuclear magnetic resonance (NMR) spectrscopy, highlighting that organic surfactants, such as oleylamine and oleic acid, have a minimal affinity toward the nanocrystal surface and engage in a highly dynamic adsorption/desorption equilibrium. We thus conclude that hot injection yields MoS2 colloids with comparable surfaces as those produced by LPE. These similarities might offer the prospect of using established procedures developed for LPE nanomaterials to postprocess colloidally synthesized dispersions of 2D colloids as processable inks.
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Affiliation(s)
- Pieter Schiettecatte
- Physics and Chemistry of Nanostructures, Ghent University, Ghent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Ghent 9000, Belgium
| | - Shalini Singh
- Department of Chemical Sciences, Unviersity of Limerick, Limerick V94T9PX, Ireland
| | - Pengshang Zhou
- Physics and Chemistry of Nanostructures, Ghent University, Ghent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Ghent 9000, Belgium
- Jiangnan University, Wuxi 214122, China
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, Ghent 9000, Belgium
- Center for Nano and Biophotonics, Ghent University, Ghent 9000, Belgium
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Giri A, Park G, Jeong U. Layer-Structured Anisotropic Metal Chalcogenides: Recent Advances in Synthesis, Modulation, and Applications. Chem Rev 2023; 123:3329-3442. [PMID: 36719999 PMCID: PMC10103142 DOI: 10.1021/acs.chemrev.2c00455] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The unique electronic and catalytic properties emerging from low symmetry anisotropic (1D and 2D) metal chalcogenides (MCs) have generated tremendous interest for use in next generation electronics, optoelectronics, electrochemical energy storage devices, and chemical sensing devices. Despite many proof-of-concept demonstrations so far, the full potential of anisotropic chalcogenides has yet to be investigated. This article provides a comprehensive overview of the recent progress made in the synthesis, mechanistic understanding, property modulation strategies, and applications of the anisotropic chalcogenides. It begins with an introduction to the basic crystal structures, and then the unique physical and chemical properties of 1D and 2D MCs. Controlled synthetic routes for anisotropic MC crystals are summarized with example advances in the solution-phase synthesis, vapor-phase synthesis, and exfoliation. Several important approaches to modulate dimensions, phases, compositions, defects, and heterostructures of anisotropic MCs are discussed. Recent significant advances in applications are highlighted for electronics, optoelectronic devices, catalysts, batteries, supercapacitors, sensing platforms, and thermoelectric devices. The article ends with prospects for future opportunities and challenges to be addressed in the academic research and practical engineering of anisotropic MCs.
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Affiliation(s)
- Anupam Giri
- Department of Chemistry, Faculty of Science, University of Allahabad, Prayagraj, UP-211002, India
| | - Gyeongbae Park
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Cheongam-Ro 77, Nam-Gu, Pohang, Gyeongbuk790-784, Korea.,Functional Materials and Components R&D Group, Korea Institute of Industrial Technology, Gwahakdanji-ro 137-41, Sacheon-myeon, Gangneung, Gangwon-do25440, Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Cheongam-Ro 77, Nam-Gu, Pohang, Gyeongbuk790-784, Korea
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5
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Schiettecatte P, Hens Z, Geiregat P. A roadmap to decipher ultrafast photophysics in two-dimensional nanomaterials. J Chem Phys 2023; 158:014202. [PMID: 36610952 DOI: 10.1063/5.0134962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Atomically thin two-dimensional (2D) semiconductors are extensively investigated for optoelectronic applications that require strong light-matter interactions. In view of such applications, it is essential to understand how (photo)excitation alters the non-linear optical response of these materials under high carrier density conditions. Broadband transient absorption (TA) spectroscopy is by now a widely used tool to study the semiconductor physics in such highly excited systems. However, the complex interplay between different many-body interactions in 2D materials produces highly congested spectral information and an ensuing non-trivial non-linear photo-response, thereby masking the desired intrinsic photophysics. Herein, we outline a concise roadmap for analyzing such congested datasets based on examples of TA analysis of various 2D materials. In particular, we emphasize the synergy between an initial qualitative understanding of the transient photo-response based on line shapes and their derivatives and a consequent quantitative spectral deconvolution backed by such insights.
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Affiliation(s)
- Pieter Schiettecatte
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
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6
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Pan Z, Liu W, Yu L, Xie Z, Sun Q, Zhao P, Chen D, Fang W, Liu B. Resonance-Induced Reduction of Interfacial Tension of Water-Methane and Improvement of Methane Solubility in Water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13594-13601. [PMID: 36299165 DOI: 10.1021/acs.langmuir.2c02392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Molecular dynamics simulations were performed to study the effect of the periodic oscillating electric field on the interface between water and methane. We propose a new strategy that utilizes oscillating electric fields to reduce the interfacial tension (IFT) between water and methane and increase the solubility of methane in water simultaneously. These are attributed to the hydrogen bond resonance induced by an electric field with a frequency close to the natural frequency of the hydrogen bond. The resonance breaks the hydrogen bond network among water molecules to the maximum, which destroys the hydration shell and reduces the cohesive action of water, thus resulting in the decrease of IFT and the increase of methane solubility. As the frequency of the electric field is close to the optimum resonant frequency of hydrogen bonds, IFT decreases from 56.43 to 5.66 mN/m; water and methane are miscible because the solubility parameter of water reduces from 47.63 to 2.85 MPa1/2, which is close to that of methane (3.43 MPa1/2). Our results provide a new idea for reducing the water-gas IFT and improving the solubility of insoluble gas in water and theoretical guidance in the fields of natural gas exploitation, hydrate generation, and nanobubble nucleation.
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Affiliation(s)
- Zhiming Pan
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Wenyu Liu
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Leyang Yu
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Zhiyang Xie
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Qing Sun
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Peihe Zhao
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Dongmeng Chen
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Wenjing Fang
- College of Science, China University of Petroleum (East China), Qingdao266580, China
| | - Bing Liu
- College of Science, China University of Petroleum (East China), Qingdao266580, China
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7
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Zhang Y, Wang Y, Guo C, Wang Y. Molybdenum Carbide-Based Photocatalysts: Synthesis, Functionalization, and Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:12739-12756. [PMID: 36245364 DOI: 10.1021/acs.langmuir.2c01887] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
As an effective non-noble, molybdenum carbide (MoxC: MoC or Mo2C) has attracted extensive attention and is regarded as a promising research area in the near future owing to its good biocompatibility, high stability, band gap adjustability, rich valence states, and excellent catalytic activity. This Perspective summarizes the recent progress and achievements for the molybdenum carbide-based catalysts. First, the crystal and band structures of molybdenum carbides are generally presented. Second, various modifying strategies for molybdenum carbides are outlined to enhance the photocatalytic performance, including doping engineering, vacancy engineering, morphology and structure engineering, and the establishment of molybdenum carbide-based composite catalysts. Finally, potential applications in the photocatalysis area of molybdenum carbide-based photocatalyst are generalized. Future development trends and perspective for this promising material are also discussed.
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Affiliation(s)
- Yifan Zhang
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
| | - Yan Wang
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
| | - Chaofei Guo
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
| | - Yong Wang
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
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8
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Rao VJ, Qi H, Berger FJ, Grieger S, Kaiser U, Backes C, Zaumseil J. Liquid Phase Exfoliation of Rubrene Single Crystals into Nanorods and Nanobelts. ACS NANO 2021; 15:20466-20477. [PMID: 34813291 DOI: 10.1021/acsnano.1c08965] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Liquid phase exfoliation (LPE) is a popular method to create dispersions of two-dimensional nanosheets from layered inorganic van der Waals crystals. Here, it is applied to orthorhombic and triclinic single crystals of the organic semiconductor rubrene with only noncovalent interactions (mainly π-π) between the molecules. Distinct nanorods and nanobelts of rubrene are formed, stabilized against aggregation in aqueous sodium cholate solution, and isolated by liquid cascade centrifugation. Selected-area electron diffraction and Raman spectroscopy confirm the crystallinity of the rubrene nanorods and nanobelts while the optical properties (absorbance, photoluminescence) of the dispersions are similar to rubrene solutions due to their randomized orientations. The formation of these stable crystalline rubrene nanostructures with only a few molecular layers by LPE confirms that noncovalent interactions in molecular crystals can be strong enough to enable mechanical exfoliation similar to inorganic layered materials.
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Affiliation(s)
- Vaishnavi J Rao
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Haoyuan Qi
- Central Facility of Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
- Center for Advancing Electronics Dresden & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
| | - Felix J Berger
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Sebastian Grieger
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Ute Kaiser
- Central Facility of Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
| | - Claudia Backes
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Jana Zaumseil
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
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9
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Maiti S, Poonia D, Schiettecatte P, Hens Z, Geiregat P, Kinge S, Siebbeles LD. Generating Triplets in Organic Semiconductor Tetracene upon Photoexcitation of Transition Metal Dichalcogenide ReS 2. J Phys Chem Lett 2021; 12:5256-5260. [PMID: 34048249 PMCID: PMC8201445 DOI: 10.1021/acs.jpclett.1c01411] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We studied the dynamics of transfer of photoexcited electronic states in a bilayer of the two-dimensional transition metal dichalcogenide ReS2 and tetracene, with the aim to produce triplets in the latter. This material combination was used as the band gap of ReS2 (1.5 eV) is slightly larger than the triplet energy of tetracene (1.25 eV). Using time-resolved optical absorption spectroscopy, transfer of photoexcited states from ReS2 to triplet states in tetracene was found to occur within 5 ps with an efficiency near 38%. This result opens up new possibilities for heterostructure design of two-dimensional materials with suitable organics to produce long-lived triplets. Triplets are of interest as sensitizers in a wide variety of applications including optoelectronics, photovoltaics, photocatalysis, and photon upconversion.
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Affiliation(s)
- Sourav Maiti
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Deepika Poonia
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Pieter Schiettecatte
- Physics
and Chemistry of Nanostructures, Ghent University, Ghent, Belgium
- Center
for Nano and Biophotonics, Ghent University, Ghent, Belgium
| | - Zeger Hens
- Physics
and Chemistry of Nanostructures, Ghent University, Ghent, Belgium
- Center
for Nano and Biophotonics, Ghent University, Ghent, Belgium
| | - Pieter Geiregat
- Physics
and Chemistry of Nanostructures, Ghent University, Ghent, Belgium
- Center
for Nano and Biophotonics, Ghent University, Ghent, Belgium
| | - Sachin Kinge
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
- Toyota
Motor Europe, Materials Research & Development, Hoge Wei 33, B-1913 Zaventem, Belgium
| | - Laurens D.A. Siebbeles
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
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Ott S, Lakmann M, Backes C. Impact of Pretreatment of the Bulk Starting Material on the Efficiency of Liquid Phase Exfoliation of WS 2. NANOMATERIALS 2021; 11:nano11051072. [PMID: 33921953 PMCID: PMC8143503 DOI: 10.3390/nano11051072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
Liquid phase exfoliation (LPE) is widely used to produce colloidal dispersions of nanomaterials, in particular two-dimensional nanosheets. The degree of exfoliation, i.e., the length to thickness aspect ratio was shown to be intrinsically limited by the ratio of in-plane to out-of-plane binding strength. In this work, we investigate whether simple pretreatment of the starting material can be used to change the in-plane to out-of-plane binding strength through mild intercalation to improve the sample quality in sonication-assisted LPE. Five different pretreatment conditions of WS2 were tested and the dispersions size-selected through centrifugation. From optical spectroscopy (extinction, Raman, photoluminescence), information on nanosheet dimension (average lateral size, layer number, monolayer size) and optical quality (relative photoluminescence quantum yield) was extracted. We find that the pretreatment has a minor impact on the length/thickness aspect ratio, but that photoluminescence quantum yield can be increased in particular using mild sonication conditions. We attribute this to the successful exfoliation of nanosheets with a lower degree of basal plane defectiveness. This work emphasizes the complexity of the exfoliation process and suggests that the role of defects has to be considered for a comprehensive picture.
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