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Jing Y, Liang K, Muir NS, Zhou H, Li Z, Palasz JM, Sorbie J, Wang C, Cushing SK, Kubiak CP, Sofer Z, Li S, Xiong W. Ultrafast Formation of Charge Transfer Trions at Molecular-Functionalized 2D MoS 2 Interfaces. Angew Chem Int Ed Engl 2024:e202405123. [PMID: 38714495 DOI: 10.1002/anie.202405123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/10/2024]
Abstract
In this work, we investigate trion dynamics occurring at the heterojunction between organometallic molecules and a monolayer transition metal dichalcogenide (TMD) with transient electronic sum frequency generation (tr-ESFG) spectroscopy. By pumping at 2.4 eV with laser pulses, we have observed an ultrafast hole transfer, succeeded by the emergence of charge-transfer trions. This observation is facilitated by the cancellation of ground state bleach and stimulated emission signals due to their opposite phases, making tr-ESFG especially sensitive to the trion formation dynamics. The presence of charge-transfer trion at molecular functionalized TMD monolayers suggests the potential for engineering the local electronic structures and dynamics of specific locations on TMDs and offers a potential for transferring unique electronic attributes of TMD to the molecular layers.
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Affiliation(s)
- Yuancheng Jing
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Kangkai Liang
- Material Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, MC 0418, La Jolla, California, 92093-0418, United States
| | - Nicole S Muir
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Hao Zhou
- Material Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, MC 0418, La Jolla, California, 92093-0418, United States
| | - Zhehao Li
- Material Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, MC 0418, La Jolla, California, 92093-0418, United States
| | - Joseph M Palasz
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Jonathan Sorbie
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Chenglai Wang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Scott K Cushing
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd, MC 127-72, Pasadena, California, 91125, United States
| | - Clifford P Kubiak
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
| | - Zdeněk Sofer
- Department of Inorganic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Shaowei Li
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
- Material Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, MC 0418, La Jolla, California, 92093-0418, United States
| | - Wei Xiong
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California, 92093-0358, United States
- Material Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, MC 0418, La Jolla, California, 92093-0418, United States
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Goswami T, Yadav DK, Bhatt H, Kaur G, Ghosh HN. Temperature dependent charge carrier dynamics in 2D ternary Cu2MoS4 nanoflakes: An effect of electron-phonon coupling. J Chem Phys 2023; 159:174705. [PMID: 37921251 DOI: 10.1063/5.0165985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 10/09/2023] [Indexed: 11/04/2023] Open
Abstract
Two-dimensional transition metal chalcogenides (2D TMCs) like MoS2, WS2 etc., have established significant dominance in the field of nanoscience and nanotechnology, owing to their unique properties like strong light-matter interaction, high carrier mobility, large photo-responsivity etc. Despite the widespread utilization of these binary TMCs, their potential in the advancement of the optoelectronic research is limited due to the constraints in band tuning and charge carrier lifetime. To overcome these limitations, ternary transition metal chalcogenides have emerged as promising alternatives. Although, the optical properties of these materials have never been explored properly. Herein, we have investigated one such promising member of this group, Cu2MoS4 (CMS) using both steady state and time-resolved spectroscopic techniques. The material exhibits a broad range of visible light absorption, peaking at 576 nm. Photoluminescence spectroscopy confirmed the presence of both band gap emission and trap state-mediated emissions. Transient absorption spectroscopy unraveled the excited state charge carrier dynamics of CMS in sub-ps timescale, upon irradiation of visible light. We found significant influence of the trap mediated recombination, while Auger process being dominant at high charge density. We extended our study in a wide temperature range (5-300 K), which reveals the impact of electron-phonon coupling strength on the band gap and charge carrier dynamics of this material. This detailed study would draw more attention toward the unexplored optical properties of ternary 2D chalcogenides and will open new avenues for the construction of 2D material-based optical devices.
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Affiliation(s)
- Tanmay Goswami
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Dharmendra Kumar Yadav
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Himanshu Bhatt
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Gurpreet Kaur
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Hirendra N Ghosh
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Odisha 752050, India
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Kaur A, Goswami T, Babu KJ, Ghosh HN. Ultrafast Hole Migration at the p-n Heterojunction of One-Dimensional SnS Nanorods and Zero-Dimensional CdS Quantum Dots. J Phys Chem Lett 2023; 14:7483-7489. [PMID: 37579185 DOI: 10.1021/acs.jpclett.3c01395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
The p-n heterojunctions fabricated from one-dimensional (1D) p-type tin sulfide nanorods (SnS NRs) decorated with n-type zero-dimensional (0D) cadmium sulfide quantum dots (CdS QDs) have gained significant research attention in energy storage devices. Herein, we have successfully synthesized a 1D/0D SnS@CdS heterostructure (HS) using a hot injection method. Structural and morphological studies clearly suggest that CdS QDs are uniformly anchored on the surface of SnS NRs, resulting in intimate contact between two components. The photoluminescence (PL) study revealed the transfer of photoexcited holes from CdS QDs to SnS NRs, which was further confirmed by transient absorption (TA) studies. TA measurements demonstrate the hole transfer from the valence band of CdS QDs to SnS NRs and delocalization of electrons between the conduction band of SnS NRs and CdS QDs in SnS@CdS HS, resulting in efficient charge separation across the p-n heterojunction. These findings will open up a new paradigm for improving the efficiency of optoelectronic devices.
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Affiliation(s)
- Arshdeep Kaur
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306, India
| | - Tanmay Goswami
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306, India
| | | | - Hirendra N Ghosh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Wang ZM, Yao CB, Wang LY, Wang X, Jiang CH, Yin HT. Charge Mobility and Strain Engineering in Two-Step MS-Grown MoS 2/Seed Layer Heterointerface and Photo-Excitation Mechanism. ACS APPLIED MATERIALS & INTERFACES 2023; 15:17364-17376. [PMID: 36973948 DOI: 10.1021/acsami.3c00706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) materials have potential application and wide development prospects in photoelectron and spintronic devices. However, the properties of different growth conditions are challenging to study in the future. This, in turn, hinders further research into 2D materials and the manufacture of high-quality devices. A comprehensive understanding of the ultrafast laser spectroscopy and dynamics that take into account the substrate-transition metal dichalcogenide (TMD) interaction is lacking. Here, the strain effect is elucidated by systematically investigating the interfacial interaction between different substrates and MoS2. The strain and interface engineering of MoS2/seeds layer heterointerface and light-matter coupling are discussed in the Raman and photoluminescence spectra. The dramatic enhanced PL originates from the phase transition of MoS2 on different substrates and electron-hole pairs dissociated by exciton screening effect. Finite-difference time-domain simulation confirmed that the electric field, magnetic field, and polarization field of the heterojunction system changed after the strain was applied. In addition, based on the dependence of physical parameters of MoS2, the relative numerical changes of physical parameters of MoS2 films on different substrates as well as the photoelectric transfer, strain, and charge doping levels on the surface or interface will provide a direction for optimizing the selection of various devices.
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Affiliation(s)
- Ze-Miao Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Cheng-Bao Yao
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Li-Yuan Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Xue Wang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Cai-Hong Jiang
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
| | - Hai-Tao Yin
- Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, Heilongjiang Province, China
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Kaur A, Goswami T, Babu KJ, Shukla A, Bhatt H, Ghosh HN. Efficient Hot Electron Transfer and Extended Separation of Charge Carriers at the 1P Hot State in Sb 2Se 3/CdSe p-n Heterojunction. J Phys Chem Lett 2022; 13:11354-11362. [PMID: 36454185 DOI: 10.1021/acs.jpclett.2c03308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Utilization of hot carriers is very crucial in improving the efficiency of solar energy devices. In this work, we have fabricated an Sb2Se3/CdSe p-n heterojunction via a cation exchange method and investigated the possibility of hot electron transfer and relaxation pathways through ultrafast spectroscopy. The enhanced intensity of the CdSe hot excitonic (1P) bleach in the heterostructure system confirmed the hot electron transfer from Sb2Se3 to CdSe. Both the 1S and 1P signals are dynamically very slow in the heterosystem, validating this charge migration phenomenon. Interestingly, recovery of the 1P signal is much slower than that of 1S. This is very unusual as 1S is the lowest-energy state. This observation indicates the strength of hot electron transfer in this unique heterojunction, which helps in increasing the carrier lifetime in the hot state. Extended separation of charge carriers and enhanced hot carrier lifetime would be extremely helpful in extracting carriers and boost the performance of optoelectronic devices.
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Affiliation(s)
- Arshdeep Kaur
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
| | - Tanmay Goswami
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
| | - K Justice Babu
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
| | - Ayushi Shukla
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
| | - Himanshu Bhatt
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab 140306,India
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085,India
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Suleman M, Lee S, Kim M, Nguyen VH, Riaz M, Nasir N, Kumar S, Park HM, Jung J, Seo Y. NaCl-Assisted Temperature-Dependent Controllable Growth of Large-Area MoS 2 Crystals Using Confined-Space CVD. ACS OMEGA 2022; 7:30074-30086. [PMID: 36061644 PMCID: PMC9434612 DOI: 10.1021/acsomega.2c03108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Due to its semiconducting nature, controlled growth of large-area chemical vapor deposition (CVD)-grown two-dimensional (2D) molybdenum disulfide (MoS2) has a lot of potential applications in photodetectors, sensors, and optoelectronics. Yet the controllable, large-area, and cost-effective growth of highly crystalline MoS2 remains a challenge. Confined-space CVD is a very promising method for the growth of highly crystalline MoS2 in a controlled manner. Herein, we report the large-scale growth of MoS2 with different morphologies using NaCl as a seeding promoter for confined-space CVD. Changes in the morphologies of MoS2 are reported by variation in the amount of seeding promoter, precursor ratio, and the growth temperature. Furthermore, the properties of the grown MoS2 are analyzed using optical microscopy, scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM). The electrical properties of the CVD-grown MoS2 show promising performance from fabricated field-effect transistors. This work provides new insight into the growth of large-area MoS2 and opens the way for its various optoelectronic and electronic applications.
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Abhijith T, E S, Suthar R, Sharma P, Thomas S, Karak S. Understanding the linear and nonlinear optical responses of few-layer exfoliated MoS 2and WS 2nanoflakes: experimental and simulation studies. NANOTECHNOLOGY 2022; 33:435702. [PMID: 35850090 DOI: 10.1088/1361-6528/ac81d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Understanding the linear and nonlinear optical (NLO) responses of two-dimensional nanomaterials is essential to effectively utilize them in various optoelectronic applications. Here, few-layer MoS2and WS2nanoflakes with lateral size less than 200 nm were prepared by liquid-phase exfoliation, and their linear and NLO responses were studied simultaneously using experimental measurements and theoretical simulations. Finite-difference time-domain (FDTD) simulations confirmed the redshift in the excitonic transitions when the thickness was increased above 10 nm indicating the layer-number dependent bandgap of nanoflakes. WS2nanoflakes exhibited around 5 times higher absorption to scattering cross-section ratio than MoS2nanoflakes at various wavelengths. Open aperture Z scan analysis of both the MoS2and WS2nanoflakes using 532 nm nanosecond laser pulses reveals strong nonlinear absorption activity with effective nonlinear absorption coefficient (βeff) of 120 cm GW-1and 180 cm GW-1, respectively, which was attributed to the combined contributions of ground, singlet excited and triplet excited state absorption. FDTD simulation results also showed the signature of strong absorption density of few layer nanoflakes which may be account for their excellent NLO characteristics. Optical limiting threshold values of MoS2and WS2nanoflakes were obtained as ∼1.96 J cm-2and 0.88 J cm-2, respectively, which are better than many of the reported values. Intensity dependent switching from saturable absorption (SA) to reverse SA was also observed for MoS2nanoflakes when the laser intensity increased from 0.14 to 0.27 GW cm-2. The present study provides valuable information to improve the selection of two-dimensional nanomaterials for the design of highly efficient linear and nonlinear optoelectronic devices.
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Affiliation(s)
- T Abhijith
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Shiju E
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Rakesh Suthar
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Punit Sharma
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sheenu Thomas
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Supravat Karak
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
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Kwon S, Jeong DY, Hong C, Oh S, Song J, Choi SH, Kim KK, Yoon S, Choi T, Yee K, Kim J, You Y, Kim D. Exciton Transfer at Heterointerfaces of MoS 2 Monolayers and Fluorescent Molecular Aggregates. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201875. [PMID: 35712754 PMCID: PMC9376849 DOI: 10.1002/advs.202201875] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Integration of distinct materials to form heterostructures enables the proposal of new functional devices based on emergent physical phenomena beyond the properties of the constituent materials. The optical responses and electrical transport characteristics of heterostructures depend on the charge and exciton transfer (CT and ET) at the interfaces, determined by the interfacial energy level alignment. In this work, heterostructures consisting of aggregates of fluorescent molecules (DY1) and 2D semiconductor MoS2 monolayers are fabricated. Photoluminescence spectra of DY1/MoS2 show quenching of the DY1 emission and enhancement of the MoS2 emission, indicating a strong electronic interaction between these two materials. Nanoscopic mappings of the light-induced contact potential difference changes rule out the CT process at the interface. Using femtosecond transient absorption spectroscopy, the rapid interfacial ET process from DY1 aggregates to MoS2 and a fourfold extension of the exciton lifetime in MoS2 are elucidated. These results suggest that the integration of 2D inorganic semiconductors with fluorescent molecules can provide versatile approaches to engineer the physical characteristics of materials for both fundamental studies and novel optoelectronic device applications.
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Affiliation(s)
- Soyeong Kwon
- Department of PhysicsEwha Womans UniversitySeoul03760Korea
| | - Dong Yeun Jeong
- Division of Chemical Engineering and Materials Scienceand Graduate Program for System Health Science and EngineeringEwha Womans UniversitySeoul03760Korea
| | - Chengyun Hong
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Korea
| | - Saejin Oh
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Korea
| | - Jungeun Song
- Department of PhysicsEwha Womans UniversitySeoul03760Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Korea
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Korea
| | - Seokhyun Yoon
- Department of PhysicsEwha Womans UniversitySeoul03760Korea
| | - Taeyoung Choi
- Department of PhysicsEwha Womans UniversitySeoul03760Korea
| | - Ki‐Ju Yee
- Department of PhysicsChungnam National UniversityDaejeon34134Korea
| | - Ji‐Hee Kim
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Korea
| | - Youngmin You
- Division of Chemical Engineering and Materials Scienceand Graduate Program for System Health Science and EngineeringEwha Womans UniversitySeoul03760Korea
| | - Dong‐Wook Kim
- Department of PhysicsEwha Womans UniversitySeoul03760Korea
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Yan F, Liao CK, Mahmoud MA, Bach SB. Electron Doping of Semiconducting MoS 2 Nanosheets by Silver or Gold Nanoclusters. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4378-4388. [PMID: 35353515 DOI: 10.1021/acs.langmuir.2c00120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Semiconducting two-dimensional (2D) materials have potential applications as ultrathin optoelectronic materials. Therefore, being able to precisely modulate the band gap is useful to improving their applicability. Electron doping of the semiconducting materials is one of the successful techniques used to modulate their band gap. Silver nanoclusters (AgNCs) or gold nanoclusters (AuNCs) a few nanometers in size can generate a high density of highly energetic hot electrons with relatively long lifetimes when photoexcited. The optical band gap of 2D MoS2 nanosheets shows different responses when integrated with different amounts of AgNCs or AuNCs due to the electron doping effect. Introducing a small amount of the nanoclusters to the surface of a MoS2 nanosheet lowered its optical band gap. Further reduction of the optical band gap of MoS2 is obtained upon tripling the amount of integrated nanoclusters. Conversely, the optical band gap of MoS2 was increased when integrated with 5 times the concentration of AuNCs and AgNCs. The optical band gap of the MoS2 nanosheets was significantly increased when integrated with an even higher concentration of AuNCs or AgNCs. The magnitude of the shift of the optical band gap of MoS2 induced by AgNCs is higher than that induced by AuNCs because the energy of LUMO of the AgNCs is higher than that of the AuNCs.
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Affiliation(s)
- Fangzhi Yan
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Chih-Kai Liao
- Department of Biomedical Engineering & Chemical Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Mahmoud A Mahmoud
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
- Department of Biomedical Engineering & Chemical Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Stephan B Bach
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
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Spontaneous formation of gold nanoparticles on MoS2 nanosheets and its impact on solution-processed optoelectronic devices. iScience 2022; 25:104120. [PMID: 35391825 PMCID: PMC8980758 DOI: 10.1016/j.isci.2022.104120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/28/2022] [Accepted: 03/16/2022] [Indexed: 11/24/2022] Open
Abstract
Understanding size-dependent properties of 2D materials is crucial for their optimized performance when incorporated through solution routes. In this work, the chemical nature of MoS2 as a function of nanosheet size is investigated through the spontaneous reduction of chloroauric acid. Microscopy studies suggest higher gold nanoparticle decoration density in smaller nanosheet sizes, resulting from higher extent of reduction. Further corroboration through surface-enhanced Raman scattering using the gold-decorated MoS2 nanosheets as substrates exhibited an enhancement factor of 1.55 × 106 for smaller nanosheets which is 7-fold higher as compared to larger nanosheets. These plasmonic-semiconductor hybrids are utilized for photodetection, where decoration is found to impact the photoresponse of smaller nanosheets the most, and is optimized to achieve responsivity of 367.5 mAW-1 and response times of ∼17 ms. The simplistic modification via solution routes and its impact on optoelectronic properties provides an enabling platform for 2D materials-based applications. Reducing agent-free Au nanoparticle decoration on aqueously dispersed 2H-MoS2. Control on Au nanoparticle decoration density through nanosheet size-selection. SERS as a probe for determining the decoration density along with microscopy. Enhanced photodetection by spontaneous modification with Au on MoS2 films.
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Hsiao FH, Chung CC, Chiang CH, Feng WN, Tzeng WY, Lin HM, Tu CM, Wu HL, Wang YH, Woon WY, Chen HC, Chen CH, Lo CY, Lai MH, Chang YM, Lu LS, Chang WH, Chen CW, Luo CW. Using Exciton/Trion Dynamics to Spatially Monitor the Catalytic Activities of MoS 2 during the Hydrogen Evolution Reaction. ACS NANO 2022; 16:4298-4307. [PMID: 35254822 DOI: 10.1021/acsnano.1c10380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The adsorption and desorption of electrolyte ions strongly modulates the carrier density or carrier type on the surface of monolayer-MoS2 catalyst during the hydrogen evolution reaction (HER). The buildup of electrolyte ions onto the surface of monolayer MoS2 during the HER may also result in the formation of excitons and trions, similar to those observed in gate-controlled field-effect transistor devices. Using the distinct carrier relaxation dynamics of excitons and trions of monolayer MoS2 as sensitive descriptors, an in situ microcell-based scanning time-resolved liquid cell microscope is set up to simultaneously measure the bias-dependent exciton/trion dynamics and spatially map the catalytic activity of monolayer MoS2 during the HER. This operando probing technique used to monitor the interplay between exciton/trion dynamics and electrocatalytic activity for two-dimensional transition metal dichalcogenides provides an excellent platform to investigate the local carrier behaviors at the atomic layer/liquid electrolyte interfaces during electrocatalytic reaction.
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Affiliation(s)
- Fu-He Hsiao
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Cheng-Chu Chung
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Chun-Hao Chiang
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Neng Feng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wen-Yen Tzeng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Hung-Min Lin
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Chien-Ming Tu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Heng-Liang Wu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Han Wang
- Department of Physics, National Central University, Taoyuan 32001, Taiwan
- Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
| | - Wei-Yen Woon
- Department of Physics, National Central University, Taoyuan 32001, Taiwan
- Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
| | - Hsiao-Chien Chen
- Center for Reliability Science and Technologies, Chang Gung University, Taoyuan 33302, Taiwan
- Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Linkou, Taoyuan 333, Taiwan
| | - Ching-Hsiang Chen
- Sustainable Energy Development Center, National Taiwan University of Science and Technology, Taipei 106335, Taiwan
| | - Chao-Yuan Lo
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei 10617, Taiwan
| | - Man-Hong Lai
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Ming Chang
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei 10617, Taiwan
| | - Li-Syuan Lu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wen-Hao Chang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), Ministry of Science and Technology, Taipei 10622, Taiwan
| | - Chun-Wei Chen
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei 10617, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), Ministry of Science and Technology, Taipei 10622, Taiwan
| | - Chih-Wei Luo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), Ministry of Science and Technology, Taipei 10622, Taiwan
- Institute of Physics and Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
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12
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Thomas A, Jinesh KB. Excitons and Trions in MoS 2 Quantum Dots: The Influence of the Dispersing Medium. ACS OMEGA 2022; 7:6531-6538. [PMID: 35252649 PMCID: PMC8892661 DOI: 10.1021/acsomega.1c05432] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Single-layer MoS2 has been reported to exhibit strong excitonic and trionic signatures in its photoluminescence (PL) spectra. Here, we report that the emission spectra of MoS2 QDs strongly depend on the dielectric constant of the solvent and the relative difference in the electronegativity between the solvent and QDs. Due to the difference in electronegativity, electrons are either added to the QD or withdrawn from it. Consequently, depending upon the dielectric permittivity and the electronegativity of the surrounding medium, the signature peaks of excitons and trions exhibit a significant change in the PL spectra of MoS2 QDs. Our findings are helpful to understand the effect of the surrounding environment on the optical properties of QDs and the importance of the selection of solvent since MoS2 QDs are potential candidates for valleytronics applications.
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13
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Goswami T, Bhatt H, Yadav DK, Saha R, Babu KJ, Ghosh HN. Probing ultrafast hot charge carrier migration in MoS 2 embedded CdS nanorods. J Chem Phys 2022; 156:034704. [PMID: 35065550 DOI: 10.1063/5.0074155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Efficient utilization of hot charge carriers is of utmost benefit for a semiconductor-based optoelectronic device. Herein, a one-dimensional (1D)/two-dimensional (2D) heterojunction was fabricated in the form of CdS/MoS2 nanorod/nanosheet composite and migration of hot charge carriers was being investigated with the help of transient absorption (TA) spectroscopy. The band alignment was such that both the electrons and holes in the CdS region tend to migrate into the MoS2 region following photoexcitation. The composite system is composed of optical signatures of both CdS and MoS2, with the dominance of CdS nanorods. In addition, the TA signal of MoS2 is substantially enhanced in the heterosystem at the cost of the diminished CdS signal, confirming the migration of charge carrier population from CdS to MoS2. This migration phenomenon was dominated by the hot carrier transfer. The hot carriers in the high energy states of CdS are preferentially migrated into the MoS2 states rather than being cooled to the band edge. The hot carrier transfer time for a 400 nm pump excitation was calculated to be 0.21 ps. This is much faster than the band edge electron transfer process, occurring at 2.0 ps time scale. We found that these migration processes are very much dependent on the applied pump photon energy. Higher energy pump photons are more efficient in the hot carrier transfer process and place these hot carriers in the higher energy states of MoS2, further extending charge carrier separation. This detailed spectroscopic investigation would help in the fabrication of better 1D/2D heterojunctions and advance the optoelectronic field.
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Affiliation(s)
- Tanmay Goswami
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Himanshu Bhatt
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Dharmendra Kumar Yadav
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Ramchandra Saha
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - K Justice Babu
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Mohali, Punjab 140306, India
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14
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Goswami T, Bhatt H, Yadav DK, Ghosh HN. Interfacing g-C 3N 4 Nanosheets with CdS Nanorods for Enhanced Photocatalytic Hydrogen Evolution: An Ultrafast Investigation. J Phys Chem B 2022; 126:572-580. [PMID: 34994569 DOI: 10.1021/acs.jpcb.1c10336] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Effective separation of electron-hole and utilization of hot charge carriers are known to be the most important factors influencing the activity of a good photocatalyst. Herein, we developed a 1D/2D heterojunction in the composite of CdS nanorod and g-C3N4 (CN) nanosheets. These two form a quasi-type-II junction at the heterointerface. The photoexcited electrons are supposed to be transferred from CN to CdS, as observed from the enhanced photoluminescence of CdS. Transient studies revealed an absolute dominance of CdS exciton formation even in the composite system, although the dynamics were substantially modified in the presence of CN. The rise time of CdS band edge excitons were increased in the composite material, owing to the migration of hot electrons from CN to CdS. The hot electron transfer time was found to be ∼0.5 ps (rate constant ∼1.98 ps-1). The excitons decay in a much slower manner than that of the pristine CdS, confirming enhanced electron population in CdS. This migration of charge carriers was found to be immensely dependent on the applied excitation photon energy. Efficient migration of charge carriers leads to enhanced photocatalytic activity in the composite and an increased evolution of H2 evolution rate was witnessed. This detailed spectroscopic study toward the mechanistic pathway of the catalytic activity of an 1D/2D heterocomposite would be immensely helpful in fabricating many other effective heterojunctions which will advance the catalysis research.
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Affiliation(s)
- Tanmay Goswami
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Himanshu Bhatt
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Dharmendra Kumar Yadav
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India.,Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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15
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Ghosh HNATH, Goswami T, Bhatt H, Yadav DK. Atomically Thin 2D Photocatalysts for Boosted H2 Production from the perspective of Transient Absorption Spectroscopy. Phys Chem Chem Phys 2022; 24:19121-19143. [DOI: 10.1039/d2cp02148j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Excited state photophysical processes play the most important role in deciding the efficiency of any photonic applications like solar light driven H2 evolution, which is considered to be the next...
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16
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Bhatt H, Goswami T, Yadav DK, Ghorai N, Shukla A, Kaur G, Kaur A, Ghosh HN. Ultrafast Hot Electron Transfer and Trap-State Mediated Charge Carrier Separation toward Enhanced Photocatalytic Activity in g-C 3N 4/ZnIn 2S 4 Heterostructure. J Phys Chem Lett 2021; 12:11865-11872. [PMID: 34874742 DOI: 10.1021/acs.jpclett.1c03356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Comprehensive understanding of charge carrier dynamics in the heterostructure based photocatalytic materials will strengthen their candidature as future solar energy harvesting resources. Here, in this work, the g-C3N4(CN)/ZnIn2S4 (ZIS) heterostructure was successfully synthesized and a direct spectroscopic correlation was established between excited-state charge carrier dynamics and enhanced photocatalytic activity using ultrafast transient absorption (TA) spectroscopy. TA analysis demonstrated the dominance of hot electron transfer over the band edge one. The photogenerated hot electrons migrated from the high-energy excitonic states of CN toward ZIS in the subpicosecond time scale. Broad-band (UV to NIR) ultrafast transient pump-probe spectroscopy revealed the collective effect of hot electron transfer as well as trap-state mediated electron delocalization in the enhanced photocatalytic H2 evolution. This work reveals the role of photogenerated carriers in the photocatalytic performance of the CN/ZIS heterostructure and would create a new avenue toward the advancement of CN based heterostructure in photocatalytic devices.
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Affiliation(s)
- Himanshu Bhatt
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Tanmay Goswami
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Dharmendra Kumar Yadav
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Nandan Ghorai
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Ayushi Shukla
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Gurpreet Kaur
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Arshdeep Kaur
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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17
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Kaur A, Goswami T, Rondiya SR, Jadhav YA, Babu KJ, Shukla A, Yadav DK, Ghosh HN. Enhanced Charge Carrier Separation and Improved Biexciton Yield at the p-n Junction of SnSe/CdSe Heterostructures: A Detailed Electrochemical and Ultrafast Spectroscopic Investigation. J Phys Chem Lett 2021; 12:10958-10968. [PMID: 34738822 DOI: 10.1021/acs.jpclett.1c02946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Tin chalcogenides (SnX, X = S, Se)-based heterostructures (HSs) are promising materials for the construction of low-cost optoelectronic devices. Here, we report the synthesis of a SnSe/CdSe HS using the controlled cation exchange reaction. The (400) plane of SnSe and the (111) plane of CdSe confirm the formation of an interface between SnSe and CdSe. The Type I band alignment is estimated for the SnSe/CdSe HS with a small conduction band offset (CBO) of 0.72 eV through cyclic voltammetry measurements. Transient absorption (TA) studies demonstrate a drastic enhancement of the CdSe biexciton signal that points toward the hot carrier transfer from SnSe to CdSe in a short time scale. The fast growth and recovery of CdSe bleach in the presence of SnSe indicate charge transfer back to SnSe. The observed delocalization of carriers in these two systems is crucial for an optoelectronic device. Our findings provide new insights into the fabrication of cost-effective photovoltaic devices based on SnSe-based heterostructures.
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Affiliation(s)
- Arshdeep Kaur
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
| | - Tanmay Goswami
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
| | - Sachin R Rondiya
- School of Energy Studies, Savitribai Phule Pune University, Pune411007, India
| | - Yogesh A Jadhav
- School of Energy Studies, Savitribai Phule Pune University, Pune411007, India
| | - K Justice Babu
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
| | - Ayushi Shukla
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
| | - Dharmendra Kumar Yadav
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, SAS Nagar, Sector 81, Mohali, Punjab140306, India
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai400085, India
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18
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Seravalli L, Bosi M, Fiorenza P, Panasci SE, Orsi D, Rotunno E, Cristofolini L, Rossi F, Giannazzo F, Fabbri F. Gold nanoparticle assisted synthesis of MoS 2 monolayers by chemical vapor deposition. NANOSCALE ADVANCES 2021; 3:4826-4833. [PMID: 36134320 PMCID: PMC9418562 DOI: 10.1039/d1na00367d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/30/2021] [Indexed: 06/16/2023]
Abstract
The use of metal nanoparticles is an established paradigm for the synthesis of semiconducting one-dimensional nanostructures. In this work we study their effect on the synthesis of two-dimensional semiconducting materials, by using gold nanoparticles for chemical vapor deposition growth of two-dimensional molybdenum disulfide (MoS2). In comparison with the standard method, the employment of gold nanoparticles allows us to obtain large monolayer MoS2 flakes, up to 20 μm in lateral size, even if they are affected by the localized overgrowth of MoS2 bilayer and trilayer islands. Important modifications of the optical and electronic properties of MoS2 triangular domains are reported, where the photoluminescence intensity of the A exciton is strongly quenched and a shift to a positive threshold voltage in back-gated field effect transistors is observed. These results indicate that the use of gold nanoparticles influences the flake growth and properties, indicating a method for possible localized synthesis of two-dimensional materials, improving the lateral size of monolayers and modifying their properties.
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Affiliation(s)
- L Seravalli
- Institute for Materials for Electronics and Magnetism (IMEM-CNR) Parco Area delle Scienze 37/a 43124 Parma Italy
| | - M Bosi
- Institute for Materials for Electronics and Magnetism (IMEM-CNR) Parco Area delle Scienze 37/a 43124 Parma Italy
| | - P Fiorenza
- Institute for Microelectronics and Microsystems (CNR-IMM) Z. I. VIII Strada 5 95121 Catania Italy
| | - S E Panasci
- Institute for Microelectronics and Microsystems (CNR-IMM) Z. I. VIII Strada 5 95121 Catania Italy
| | - D Orsi
- Department of Mathematical, Physical and Computer Sciences, University of Parma Parco Area delle Scienze 7/a 43124 Parma Italy
| | - E Rotunno
- Istituto Nanoscienze-CNR via G Campi 213/a 41125 Modena Italy
| | - L Cristofolini
- Department of Mathematical, Physical and Computer Sciences, University of Parma Parco Area delle Scienze 7/a 43124 Parma Italy
| | - F Rossi
- Institute for Materials for Electronics and Magnetism (IMEM-CNR) Parco Area delle Scienze 37/a 43124 Parma Italy
| | - F Giannazzo
- Institute for Microelectronics and Microsystems (CNR-IMM) Z. I. VIII Strada 5 95121 Catania Italy
| | - F Fabbri
- NEST, Istituto Nanoscienze - CNR, Scuola Normale Superiore Piazza San Silvestro 12 56127 Pisa Italy
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19
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Goswami T, Bhatt H, Babu KJ, Kaur G, Ghorai N, Ghosh HN. Ultrafast Insights into High Energy (C and D) Excitons in Few Layer WS 2. J Phys Chem Lett 2021; 12:6526-6534. [PMID: 34242025 DOI: 10.1021/acs.jpclett.1c01627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High energy (C and D) excitons possess extraordinary influence over the optical properties of atomically thin transition metal dichalcogenides (TMDCs), and the comprehensive understanding of these would play a pivotal role in advancing research on 2D optoelectronics. Herein, we employed transient absorption spectroscopy to monitor the underlying photophysical processes involved with different excitonic features in few layer WS2, modeled as a TMDC representative. We observed a strong intervalley coupling across the momentum space and proposed the most plausible relaxation pathway for different excitons in few layer scenario. C and D exciton dynamics were significantly slower as compared to canonical A and B excitons, as a consequence of the indirect Λ-Γ relaxation in C and D and direct K-K combination in A and B. Most importantly, all four excitons emerge in the system and influence each other irrespective of the incident photon energy, which would be extremely impactful in fabricating wide range photonic devices.
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Affiliation(s)
- Tanmay Goswami
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Himanshu Bhatt
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - K Justice Babu
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Gurpreet Kaur
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Nandan Ghorai
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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20
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Das S, Wang Y, Dai Y, Li S, Sun Z. Ultrafast transient sub-bandgap absorption of monolayer MoS 2. LIGHT, SCIENCE & APPLICATIONS 2021; 10:27. [PMID: 33514690 PMCID: PMC7846580 DOI: 10.1038/s41377-021-00462-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/21/2020] [Accepted: 12/30/2020] [Indexed: 05/23/2023]
Abstract
The light-matter interaction in materials is of remarkable interest for various photonic and optoelectronic applications, which is intrinsically determined by the bandgap of the materials involved. To extend the applications beyond the bandgap limit, it is of great significance to study the light-matter interaction below the material bandgap. Here, we report the ultrafast transient absorption of monolayer molybdenum disulfide in its sub-bandgap region from ~0.86 µm to 1.4 µm. Even though this spectral range is below the bandgap, we observe a significant absorbance enhancement up to ~4.2% in the monolayer molybdenum disulfide (comparable to its absorption within the bandgap region) due to pump-induced absorption by the excited carrier states. The different rise times of the transient absorption at different wavelengths indicate the various contributions of the different carrier states (i.e., real carrier states in the short-wavelength region of ~<1 µm, and exciton states in the long wavelength region of ~>1 µm). Our results elucidate the fundamental understanding regarding the optical properties, excited carrier states, and carrier dynamics in the technologically important near-infrared region, which potentially leads to various photonic and optoelectronic applications (e.g., excited-state-based photodetectors and modulators) of two-dimensional materials and their heterostructures beyond their intrinsic bandgap limitations.
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Affiliation(s)
- Susobhan Das
- Department of Electronics and Nanoengineering, Aalto University, 02150, Espoo, Finland.
| | - Yadong Wang
- Department of Electronics and Nanoengineering, Aalto University, 02150, Espoo, Finland
| | - Yunyun Dai
- Department of Electronics and Nanoengineering, Aalto University, 02150, Espoo, Finland
| | - Shisheng Li
- International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Zhipei Sun
- Department of Electronics and Nanoengineering, Aalto University, 02150, Espoo, Finland.
- QTF Centre of Excellence, Department of Applied Physics, Aalto University, Espoo, Finland.
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21
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Xu C, Yong HW, He J, Long R, Cadore AR, Paradisanos I, Ott AK, Soavi G, Tongay S, Cerullo G, Ferrari AC, Prezhdo OV, Loh ZH. Weak Distance Dependence of Hot-Electron-Transfer Rates at the Interface between Monolayer MoS 2 and Gold. ACS NANO 2021; 15:819-828. [PMID: 33347267 DOI: 10.1021/acsnano.0c07350] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electron transport across the transition-metal dichalcogenide (TMD)/metal interface plays an important role in determining the performance of TMD-based optoelectronic devices. However, the robustness of this process against structural heterogeneities remains unexplored, to the best of our knowledge. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and atomic force microscopy to investigate the spatially resolved hot-electron-transfer dynamics at the monolayer (1L) MoS2/Au interface. A spatially heterogeneous distribution of 1L-MoS2/Au gap distances, along with the sub-80 nm spatial- and sub-60 fs temporal resolution of TR-PEEM, permits the simultaneous measurement of electron-transfer rates across a range of 1L-MoS2/Au distances. These decay exponentially as a function of distance, with an attenuation coefficient β ∼ 0.06 ± 0.01 Å-1, comparable to molecular wires. Ab initio simulations suggest that surface plasmon-like states mediate hot-electron-transfer, hence accounting for its weak distance dependence. The weak distance dependence of the interfacial hot-electron-transfer rate indicates that this process is insensitive to distance fluctuations at the TMD/metal interface, thus motivating further exploration of optoelectronic devices based on hot carriers.
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Affiliation(s)
- Ce Xu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Hui Wen Yong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jinlu He
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Ioannis Paradisanos
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Anna K Ott
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
- Institute for Solid State Physics, Abbe Center of Photonics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano Italy
- IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Optical Fibre Technology, The Photonics Institute, Nanyang Technological University, Singapore 639798, Singapore
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22
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Sarkar AS, Konidakis I, Demeridou I, Serpetzoglou E, Kioseoglou G, Stratakis E. Robust B-exciton emission at room temperature in few-layers of MoS 2:Ag nanoheterojunctions embedded into a glass matrix. Sci Rep 2020; 10:15697. [PMID: 32973224 PMCID: PMC7518262 DOI: 10.1038/s41598-020-72899-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/28/2020] [Indexed: 01/30/2023] Open
Abstract
Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS2) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications. Although significant effort has been devoted towards enhancing or manipulating the excitonic emission in MoS2 monolayers, the excitonic emission in few-layers MoS2 has been largely unexplored. Here, we put forward a novel nano-heterojunction system, prepared with a non-lithographic process, to enhance and control such emission. It is based on the incorporation of few-layers MoS2 into a plasmonic silver metaphosphate glass (AgPO3) matrix. It is shown that, apart from the enhancement of the emission of both A- and B-excitons, the B-excitonic emission dominates the PL intensity. In particular, we observe an almost six-fold enhancement of the B-exciton emission, compared to control MoS2 samples. This enhanced PL at room temperature is attributed to an enhanced exciton-plasmon coupling and it is supported by ultrafast time-resolved spectroscopy that reveals plasmon-enhanced electron transfer that takes place in Ag nanoparticles-MoS2 nanoheterojunctions. Our results provide a great avenue to tailor the emission properties of few-layers MoS2, which could find application in emerging valleytronic devices working with B excitons.
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Affiliation(s)
- Abdus Salam Sarkar
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece.
| | - Ioannis Konidakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece
| | - Ioanna Demeridou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece
- Physics Department, University of Crete, 710 03, Heraklion, Crete, Greece
| | - Efthymis Serpetzoglou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece
- Physics Department, University of Crete, 710 03, Heraklion, Crete, Greece
| | - George Kioseoglou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece
- Department of Materials Science and Technology, University of Crete, 710 03, Heraklion, Crete, Greece
| | - Emmanuel Stratakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, 700 13, Heraklion, Crete, Greece.
- Physics Department, University of Crete, 710 03, Heraklion, Crete, Greece.
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23
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Zimmermann JE, Li B, Hone JC, Höfer U, Mette G. Second-harmonic imaging microscopy for time-resolved investigations of transition metal dichalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:485901. [PMID: 32716316 DOI: 10.1088/1361-648x/aba946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Two-dimensional transition metal dichalcogenides (TMD) have shown promise for various applications in optoelectronics and so-called valleytronics. Their operation and performance strongly depend on the stacking of individual layers. Here, optical second-harmonic generation in imaging mode is shown to be a versatile tool for systematic time-resolved investigations of TMD monolayers and heterostructures in consideration of the material's structure. Large sample areas can be probed without the need of any mapping or scanning. By means of polarization dependent measurements, the crystalline orientation of monolayers or the stacking angles of heterostructures can be evaluated for the whole field of view. Pump-probe experiments then allow to correlate observed transient changes of the second-harmonic response with the underlying structure. The corresponding time-resolution is virtually limited by the pulse duration of the used laser. As an example, polarization dependent and time-resolved measurements on mono- and multilayer MoS2flakes grown on a SiO2/ Si(001) substrate are presented.
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Affiliation(s)
- J E Zimmermann
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - B Li
- Department of Mechanical Engineering, Columbia University, New York 10027, United States of America
| | - J C Hone
- Department of Mechanical Engineering, Columbia University, New York 10027, United States of America
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
| | - G Mette
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany
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Shukla A, Kaur G, Babu KJ, Ghorai N, Goswami T, Kaur A, Ghosh HN. Effect of Confinement on the Exciton and Biexciton Dynamics in Perovskite 2D-Nanosheets and 3D-Nanocrystals. J Phys Chem Lett 2020; 11:6344-6352. [PMID: 32663017 DOI: 10.1021/acs.jpclett.0c01853] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The performance of the high-end optoelectronic devices is essentially influenced by the intrinsic relaxation mechanisms pursued by the hot carriers. Therefore, the key toward achieving progression in such fields lies in developing a complete understanding of the involved carrier cooling dynamics. In this work, an endeavor has been made to highlight the difference in the cooling mechanisms in 2D CsPbBr3 nanosheets (NSs) and their 3D counterpart nanocrystals (NCs) with the aid of femtosecond broad-band pump-probe spectroscopy, varying the excitation energies. The exciton and biexciton dynamics in both systems are found to be retarded upon increasing the excitation energy. However, in contrast to 3D NCs, carrier cooling is found to be faster in the 2D system, regardless of the excitation energy used, attributing this to less efficient charge screening by Fröhlich interaction in low-dielectric medium. A similar trend is replicated in the biexciton formation rate since the formation is also found to be faster in NSs compared to NCs.
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Affiliation(s)
- Ayushi Shukla
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - Gurpreet Kaur
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - K Justice Babu
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - Nandan Ghorai
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - Tanmay Goswami
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - Arshdeep Kaur
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
| | - Hirendra N Ghosh
- Institute of Nano Science and Technology, Mohali, Punjab 160062, India
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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