Modulating the Optoelectronic Properties of MoS₂ by Highly Oriented Dipole-Generating Monolayers

Abstract

The noncovalent functionalization of two-dimensional materials (2DMs) with bespoke organic molecules is of central importance for future nanoscale electronic devices. Of particular interest is the incorporation of molecular functionalities that can modulate the physicochemical properties of the 2DMs via noninvasive external stimuli. In this study, we present the reversible modulation of the photoluminescence, spectroscopic properties (Raman), and charge transport characteristics of molybdenum disulfide (MoS2)-based devices via photoisomerization of a self-assembled monolayer of azobenzene-modified triazatriangulene molecules. The observed (opto)­electronic modulations are explained by the n-type doping of the MoS2 lattice induced by the photoisomerization of the highly ordered azobenzene monolayer. This novel behavior could have profound effects on future composite 2DM-based (opto)­electronics.

Bright excitonic multiplexing mediated by dark exciton transition in two-dimensional TMDCs at room temperature

“…Considering that the dark transition prompts the population of the A d -excitonic state, the relation to the observed B-emission feature can be explained by several excitonic interaction routs, which occur on a faster timescale than the A d -lifetime, 30 such as intravalley excitonic exchange, 24 intervalley momentum-forbidden excitonic interaction 33 and the formation of charged excitons. 41–44 The latter, however, can be excluded due to the lack of alteration in the B-signal under gate bias (see ESI† note 2); while an interplay between the neutral and charged excitons can be observed for the A-exciton regime. Additionally, the population of the A b - seems to increase by the application of positive voltage with no apparent change of the B-emission, indicating a less effective bright-to-bright intravalley excitonic exchange.…”

Edge-Based Two-Dimensional α-In2Se3–MoS2 Ferroelectric Field Effect Device

“…The same PL characteristics are also obtained following 10 min after gate voltage withdrawal indicating the potential for efficient PL emission switching and memorization (Figure 6c and Figure S4a). Similar PL variations were observed in MoS 2 -based field effect devices 59 and in ferroelectric lithium niobate (LiNbO 3 )based MoSe 2 heterostructures. 60 In addition, a slight redshift of the A-exciton is observed at positive applied back gate potential and is attributed to the increase in negatively charged Trion concentration.…”

First-principles investigation of in-plane anisotropies in XYTe4 monolayers with X = Hf, Zr, Ti and Y = Si, Ge

“…Compared with bulk materials, 2D materials such as transition metal dichalcogenides (TMDs), [2][3][4] boron-nitride (BN) 5,6 and black phosphorus (BP) 7,8 possess excellent electronic, mechanical and transport properties, which make them promising for various electronic 9,10 and optoelectronic applications. 11,12 Recently, 2D ternary compounds have gradually attracted widespread attention because of their distinctive structures and exotic properties, [13][14][15][16][17] which originate from the stoichiometric variation and synergistic effect in contrast to the 2D unitary and binary counterparts. [18][19][20][21] Janus MXY (M = Mo or W, X/Y = S, Se, or Te) structures are reported with large out-of-plane piezoelectricity owing to the atoms with different electronegativity values within the layers, 13,22 which is not found in intrinsic TMD materials.…”

“…Compared with bulk materials, 2D materials such as transition metal dichalcogenides (TMDs), 2–4 boron-nitride (BN) 5,6 and black phosphorus (BP) 7,8 possess excellent electronic, mechanical and transport properties, which make them promising for various electronic 9,10 and optoelectronic applications. 11,12…”