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Walke P, Kaupmees R, Grossberg-Kuusk M, Krustok J. Unusual Defect-Related Room-Temperature Emission from WS 2 Monolayers Synthesized through a Potassium-Based Precursor. ACS OMEGA 2023; 8:37958-37970. [PMID: 37867715 PMCID: PMC10586178 DOI: 10.1021/acsomega.3c03476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 08/29/2023] [Indexed: 10/24/2023]
Abstract
Alkali-metal-based synthesis of transition metal dichalcogenide (TMD) monolayers is an established strategy for both ultralarge lateral growth and promoting the metastable 1T phase. However, whether this can also lead to modified optical properties is underexplored, with reported photoluminescence (PL) spectra from semiconducting systems showing little difference from more traditional syntheses. Here, we show that the growth of WS2 monolayers from a potassium-salt precursor can lead to a pronounced low-energy emission in the PL spectrum. This is seen 200-300 meV below the A exciton and can dominate the signal at room temperature. The emission is spatially heterogeneous, and its presence is attributed to defects in the layer due to sublinear intensity power dependence, a noticeable aging effect, and insensitivity to washing in water and acetone. Interestingly, statistical analysis links the band to an increase in the width of the A1g Raman band. The emission can be controlled by altering when hydrogen is introduced into the growth process. This work demonstrates intrinsic and intense defect-related emission at room temperature and establishes further opportunities for tuning TMD properties through alkali-metal precursors.
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Affiliation(s)
- Peter Walke
- Department of Materials and
Environmental Technology, Tallinn University
of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Reelika Kaupmees
- Department of Materials and
Environmental Technology, Tallinn University
of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Maarja Grossberg-Kuusk
- Department of Materials and
Environmental Technology, Tallinn University
of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Jüri Krustok
- Department of Materials and
Environmental Technology, Tallinn University
of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
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Zou J, Zhu R, Wang J, Meng H, Wang Z, Chen H, Weng YX. Coherent Phonon-Mediated Many-Body Interaction in Monolayer WSe 2. J Phys Chem Lett 2023; 14:4657-4665. [PMID: 37167104 DOI: 10.1021/acs.jpclett.3c00870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Due to the strong Coulomb interaction, the optical and electrical properties of two-dimensional transition metal dichalcogenides (TMDCs) are greatly determined by the emergence of many-body complexes such as excitons or trions. To fully realize the potential functionalities of these atomically thin materials, a comprehensive understanding of their many-body interaction mechanism is essential. Here, using the advanced femtosecond two-dimensional electronic spectroscopy technique combined with broadband transient absorption spectroscopy, a strong electron-exciton coupling effect in monolayer WSe2 following the ultrafast photoexcitation is revealed. We demonstrate that such many-body complexes can be generated effectively through the band-edge optical excitation, with a ∼1.5 ps stabilization process. The coherent optical phonon plays a dominant role in this electron-exciton interaction, and the coherence of the electron (exciton)-phonon coupling can last for ∼4.5 ps. This finding offers new insight into the formation mechanism of photoinduced many-body complexes in TMDCs.
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Affiliation(s)
- Jiading Zou
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruidan Zhu
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiayu Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanting Meng
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yu-Xiang Weng
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Yu Y, Fan X, Liu S, Yao L. Competition mechanism of exciton decay channels in the stacked multilayer tungsten sulfide. OPTICS EXPRESS 2023; 31:9350-9361. [PMID: 37157507 DOI: 10.1364/oe.484524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The competition mechanism of exciton decay channels in the multilayer TMDs remains poorly understood. Here, the exciton dynamics in the stacked WS2 was studied. The exciton decay processes are divided into the fast and slow decay processes, which are dominated by the exciton-exciton annihilation (EEA) and defect-assisted recombination (DAR), respectively. The lifetime of EEA is on the order of hundreds of femtoseconds (400∼1100 fs). It is decreased initially, followed by an increase with adding layer thickness, which can be attributed to the competition between phonon-assisted effect and defect effect. The lifetime of DAR is on the timescale of hundreds of picoseconds (200∼800 ps), which is determined by the defect density especially in a high injected carrier density.
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Markeev PA, Najafidehaghani E, Samu GF, Sarosi K, Kalkan SB, Gan Z, George A, Reisner V, Mogyorosi K, Chikan V, Nickel B, Turchanin A, de Jong MP. Exciton Dynamics in MoS 2-Pentacene and WSe 2-Pentacene Heterojunctions. ACS NANO 2022; 16:16668-16676. [PMID: 36178781 PMCID: PMC9620401 DOI: 10.1021/acsnano.2c06144] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
We measured the exciton dynamics in van der Waals heterojunctions of transition metal dichalcogenides (TMDCs) and organic semiconductors (OSs). TMDCs and OSs are semiconducting materials with rich and highly diverse optical and electronic properties. Their heterostructures, exhibiting van der Waals bonding at their interfaces, can be utilized in the field of optoelectronics and photovoltaics. Two types of heterojunctions, MoS2-pentacene and WSe2-pentacene, were prepared by layer transfer of 20 nm pentacene thin films as well as MoS2 and WSe2 monolayer crystals onto Au surfaces. The samples were studied by means of transient absorption spectroscopy in the reflectance mode. We found that A-exciton decay by hole transfer from MoS2 to pentacene occurs with a characteristic time of 21 ± 3 ps. This is slow compared to previously reported hole transfer times of 6.7 ps in MoS2-pentacene junctions formed by vapor deposition of pentacene molecules onto MoS2 on SiO2. The B-exciton decay in WSe2 shows faster hole transfer rates for WSe2-pentacene heterojunctions, with a characteristic time of 7 ± 1 ps. The A-exciton in WSe2 also decays faster due to the presence of a pentacene overlayer; however, fitting the decay traces did not allow for the unambiguous assignment of the associated decay time. Our work provides important insights into excitonic dynamics in the growing field of TMDC-OS heterojunctions.
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Affiliation(s)
- Pavel A. Markeev
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AEEnschede, The Netherlands
| | - Emad Najafidehaghani
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Gergely F. Samu
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Krisztina Sarosi
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Sirri Batuhan Kalkan
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Ziyang Gan
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Antony George
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Veronika Reisner
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Karoly Mogyorosi
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Viktor Chikan
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
- Department
of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas66506-0401, United States
| | - Bert Nickel
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Andrey Turchanin
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Michel P. de Jong
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AEEnschede, The Netherlands
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Contreras D, Yuson JM, Eroglu ZE, Bahrami P, Hadad Zavareh HS, Boulesbaa A. Ultrafast electron transfer at the interface of gold nanoparticles and methylene blue molecular adsorbates. Phys Chem Chem Phys 2022; 24:17271-17278. [PMID: 35797725 DOI: 10.1039/d2cp02568j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Due to their unique property of possessing localized surface plasmon resonance (LSPR), metal nanoparticles (MNPs) have drastically impacted many applications. For instance, local field enhancement through LSPRs and plasmonic hot electron transfer are known to enhance the efficiency of MNP-based photoreactions. Here, we report on the ultrafast electron transfer from gold nanoparticles (Au-NPs) to methylene blue (MB) molecular adsorbate using femtosecond pump-probe and steady-state absorption and emission spectroscopy techniques. Although the energy band alignment of the interface allows both dipole-dipole Förster resonance energy transfer (FRET) and charge transfer, because the MB emission intensity at the Au-NPs/MB nanocomposite decreased by a factor of ∼3.6, the FRET process was ruled out. Selective excitation of LSPRs at the Au-NPs/MB nanocomposite sample in pump-probe experiments led to the formation of the MB ground-state depletion and a positive induced absorption at wavelengths shorter than ∼500 nm, which was attributed to the shoulder of the MB- anion absorption. Furthermore, despite the fact that the concentration of Au-NPs in the nanocomposite sample is the same as that in the Au-NPs solution, the initial intensity of the LSPR depletion signal was about six times weaker than that in the Au-NPs sample. These observations suggest that electron transfer from excited Au-NPs to MB adsorbates took place on a time-scale that is shorter than the ∼50 fs experimental temporal resolution.
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Affiliation(s)
- Dillon Contreras
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
| | - Joie M Yuson
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
| | - Zeynep E Eroglu
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
| | - Pouya Bahrami
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
| | - Hoda Sadeghi Hadad Zavareh
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
| | - Abdelaziz Boulesbaa
- Department of Chemistry & Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, 91330 CA, USA.
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