THE ELECTRONIC STRUCTURE AT ORGANIC–2D MATERIAL HETEROINTERFACES

2021 ◽  
pp. 2140003
Author(s):  
YU LI HUANG ◽  
ANDREW THYE SHEN WEE
Keyword(s):  
Charge Transfer ◽  
Electronic Structures ◽  
Transition Metal Dichalcogenides ◽  
2D Material ◽  
Physical Mechanisms ◽  
Wide Range ◽  
Fundamental Understanding ◽  
Potential Applications ◽  
Metal Dichalcogenides ◽  
Interfacial Charge

Organic–2D material heterostructures have attracted intensive research interest due to their intriguing properties, with a wide range of potential applications in multifunctional flexible electronic and optoelectronic devices. Central to the realization of such devices is a fundamental understanding of the electronic structures at organic–2D material heterointerfaces. The energy level alignment (ELA) at the interface is of paramount importance because it determines the charge transfer barriers between the two materials in contact. In this paper, we discuss the physical mechanisms determining the ELAs, with special attention on interfacial charge transfer at the heterostructures. We review the current understanding of electronic properties at the heterointerfaces formed by the integration of organics with graphene and 2D transition metal dichalcogenides (TMDs), and conclude with a perspective on the future development of organic–2D material heterostructure.

scholarly journals Long-lived charge separation following pump-wavelength–dependent ultrafast charge transfer in graphene/WS2 heterostructures

2021 ◽  
Vol 7 (9) ◽  
pp. eabd9061
Author(s):  
Shuai Fu ◽  
Indy du Fossé ◽  
Xiaoyu Jia ◽  
Jingyin Xu ◽  
Xiaoqing Yu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Transition Metal Dichalcogenides ◽  
Thermionic Emission ◽  
Great Promise ◽  
Metal Dichalcogenides ◽  
Ultrafast Charge Transfer ◽  
Device Operation ◽  
Interfacial Charge

Van der Waals heterostructures consisting of graphene and transition metal dichalcogenides have shown great promise for optoelectronic applications. However, an in-depth understanding of the critical processes for device operation, namely, interfacial charge transfer (CT) and recombination, has so far remained elusive. Here, we investigate these processes in graphene-WS2 heterostructures by complementarily probing the ultrafast terahertz photoconductivity in graphene and the transient absorption dynamics in WS2 following photoexcitation. We observe that separated charges in the heterostructure following CT live extremely long: beyond 1 ns, in contrast to ~1 ps charge separation reported in previous studies. This leads to efficient photogating of graphene. Furthermore, for the CT process across graphene-WS2 interfaces, we find that it occurs via photo-thermionic emission for sub-A-exciton excitations and direct hole transfer from WS2 to the valence band of graphene for above-A-exciton excitations. These findings provide insights to further optimize the performance of optoelectronic devices, in particular photodetection.

scholarly journals Interface Engineering for Perovskite Solar Cells Based on 2D-Materials: A Physics Point of View

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5843
Author(s):  
Rosaria Verduci ◽  
Antonio Agresti ◽  
Valentino Romano ◽  
Giovanna D’Angelo
Keyword(s):  
Solar Cells ◽  
Transition Metal ◽  
2D Materials ◽  
Low Cost ◽  
Transition Metal Dichalcogenides ◽  
Perovskite Solar Cells ◽  
Precursor Solution ◽  
Point Of View ◽  
Physical Mechanisms ◽  
Metal Dichalcogenides

The last decade has witnessed the advance of metal halide perovskites as a promising low-cost and efficient class of light harvesters used in solar cells (SCs). Remarkably, the efficiency of lab-scale perovskite solar cells (PSCs) reached a power conversion efficiency of 25.5% in just ~10 years of research, rivalling the current record of 26.1% for Si-based PVs. To further boost the performances of PSCs, the use of 2D materials (such as graphene, transition metal dichalcogenides and transition metal carbides, nitrides and carbonitrides) has been proposed, thanks to their remarkable optoelectronic properties (that can be tuned with proper chemical composition engineering) and chemical stability. In particular, 2D materials have been demonstrated as promising candidates for (i) accelerating hot carrier transfer across the interfaces between the perovskite and the charge extraction layers; (ii) improving the crystallization of the perovskite layers (when used as additives in the precursor solution); (iii) favoring electronic bands alignment through tuning of the work function. In this mini-review, we discuss the physical mechanisms underlying the increased efficiency of 2D material-based PSCs, focusing on the three aforementioned effects.

Intriguing electronic structures and optical properties of two-dimensional van der Waals heterostructures of Zr2CT2 (T = O, F) with MoSe2 and WSe2

2018 ◽  
Vol 6 (11) ◽  
pp. 2830-2839 ◽  
Author(s):  
Gul Rehman ◽  
S. A. Khan ◽  
B. Amin ◽  
Iftikhar Ahmad ◽  
Li-Yong Gan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Material Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Van Der Waals Heterostructures ◽  
Metal Dichalcogenides

Based on (hybrid) first-principles calculations, material properties (structural, electronic, vibrational, optical, and photocatalytic) of van der Waals heterostructures and their corresponding monolayers (transition metal dichalcogenides and MXenes) are investigated.

Strong coupling in two-dimensional materials-based nanostructures: a review

2022 ◽  
Author(s):  
Ye Ming Qing ◽  
Yongze Ren ◽  
Dangyuan Lei ◽  
Hui Feng Ma ◽  
Tie Jun Cui
Keyword(s):  
Strong Coupling ◽  
Coupling Effect ◽  
Transition Metal Dichalcogenides ◽  
Hybrid Nanostructures ◽  
Two Dimensional ◽  
Strong Light ◽  
Two Dimensional Materials ◽  
Potential Applications ◽  
Metal Dichalcogenides ◽  
Emission Behavior

Abstract Strong interaction between electromagnetic radiation and matter leads to the formation of hybrid light-matter states, making the absorption and emission behavior different from those of the uncoupled states. Strong coupling effect results in the famous Rabi splitting and the emergence of new polaritonic eigenmodes, exhibiting spectral anticrossing behavior and unique energy-transfer properties. In recent years, there has been a rapidly increasing number of works focusing on strong coupling between nanostructures and two-dimensional materials (2DMs), because of the exceptional properties and applications they demonstrate. Here, we review the significant recent advances and important developments of strong light-matter interactions in 2DMs-based nanostructures. We adopt the coupled oscillator model to describe the strong coupling and give an overview of various hybrid nanostructures to realize this regime, including graphene-based nanostructures, black phosphorus-based nanostructures, transition-metal dichalcogenides-based nanostructures, etc. In addition, we discuss potential applications that can benefit from these effects and conclude our review with a perspective on the future of this rapidly emerging field.

Tailorable multifunctionalities in ultrathin 2D Bi-based layered supercell structures

Nanoscale ◽  
2021 ◽  
Author(s):  
Zihao He ◽  
Xingyao Gao ◽  
Di Zhang ◽  
Ping Lu ◽  
Xuejing Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Ferromagnetic Behavior ◽  
Two Dimensional ◽  
Next Generation ◽  
Layered Oxide ◽  
Nanoelectronic Devices ◽  
Potential Applications ◽  
Metal Dichalcogenides

Two-dimensional (2D) materials with robust ferromagnetic behavior have attracted great interest because of their potential applications in next-generation nanoelectronic devices. Aside from graphene and transition metal dichalcogenides, Bi-based layered oxide...

scholarly journals Prediction of the structural and electronic properties of MoxTi1−xS2 monolayers via first principle simulations

2020 ◽  
Vol 10 ◽  
pp. 184798042095509
Author(s):  
Ankit Kumar Verma ◽  
Federico Raffone ◽  
Giancarlo Cicero
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Transition Metal Dichalcogenides ◽  
Stable Phase ◽  
Two Dimensional ◽  
Electron Hole ◽  
Effective Electron ◽  
Wide Range ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides have gained great attention because of their peculiar physical properties that make them interesting for a wide range of applications. Lately, alloying between different transition metal dichalcogenides has been proposed as an approach to control two-dimensional phase stability and to obtain compounds with tailored characteristics. In this theoretical study, we predict the phase diagram and the electronic properties of Mo xTi1− xS2 at varying stoichiometry and show how the material is metallic, when titanium is the predominant species, while it behaves as a p-doped semiconductor, when approaching pure MoS2 composition. Correspondingly, the thermodynamically most stable phase switches from the tetragonal to the hexagonal one. Further, we present an example which shows how the proposed alloys can be used to obtain new vertical two-dimensional heterostructures achieving effective electron/hole separation.

scholarly journals Self-similar transport, spin polarization and thermoelectricity in complex silicene structures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. Rodríguez-González ◽  
L. M. Gaggero-Sager ◽  
I. Rodríguez-Vargas
Keyword(s):  
Physical Properties ◽  
Spin Polarization ◽  
Structural Parameters ◽  
Transition Metal Dichalcogenides ◽  
Monolayer Graphene ◽  
Complex Geometries ◽  
2D Material ◽  
Metal Dichalcogenides ◽  
Self Similar ◽  
Mott Formula

Abstract 2D materials open the possibility to study Dirac electrons in complex self-similar geometries. The two-dimensional nature of materials like graphene, silicene, phosphorene and transition-metal dichalcogenides allow the nanostructuration of complex geometries through metallic electrodes, interacting substrates, strain, etc. So far, the only 2D material that presents physical properties that directly reflect the characteristics of the complex geometries is monolayer graphene. In the present work, we show that silicene nanostructured in complex fashion also displays self-similar characteristics in physical properties. In particular, we find self-similar patterns in the conductance, spin polarization and thermoelectricity of Cantor-like silicene structures. These complex structures are generated by modulating electrostatically the silicene local bandgap in Cantor-like fashion along the structure. The charge carriers are described quantum relativistically by means of a Dirac-like Hamiltonian. The transfer matrix method, the Landauer–Büttiker formalism and the Cutler–Mott formula are used to obtain the transmission, transport and thermoelectric properties. We numerically derive scaling rules that connect appropriately the self-similar conductance, spin polarization and Seebeck coefficient patterns. The scaling rules are related to the structural parameters that define the Cantor-like structure such as the generation and length of the system as well as the height of the potential barriers. As far as we know this is the first time that a 2D material beyond monolayer graphene shows self-similar quantum transport as well as that transport related properties like spin polarization and thermoelectricity manifest self-similarity.

scholarly journals An emerging Janus MoSeTe material for potential applications in optoelectronic devices

2019 ◽  
Vol 7 (39) ◽  
pp. 12312-12320 ◽  
Author(s):  
Xiaoyong Yang ◽  
Deobrat Singh ◽  
Zhitong Xu ◽  
Ziwei Wang ◽  
Rajeev Ahuja
Keyword(s):  
First Principles ◽  
Transition Metal Dichalcogenides ◽  
Chemical Properties ◽  
Detailed Comparison ◽  
Physical And Chemical Properties ◽  
First Principles Calculations ◽  
Potential Applications ◽  
Metal Dichalcogenides ◽  
Physical And Chemical ◽  
And Chemical Properties

Motivated by the extraordinary physical and chemical properties of Janus transition-metal dichalcogenides (TMDs) due to the change of the crystal field originating from their asymmetry structures, the electronic and optical properties of the MoSeTe monolayer in 2H and 1T phases are systematically studied by first-principles calculations, and a detailed comparison with the parental MoSe2 and MoTe2 monolayer is made.

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