PL enhancement of MoS2 by Au nanoparticles

Abstract

Molybdenum disulphide (MoS2), a layered quasi-two dimensional (2D) chalcogenide material, is a subject of intense research because of its electronic, optical, mechanical and physicochemical properties. Since the monolayer MoS2 is a direct-gap seminconductor, it is widely used in the field of light-emitting area. However, its photoluminescence (PL) efficiency is very low due to excessive doping in monolayer MoS2 and rich non-radiative centers. In this letter, we reportits synthesis using the gold nanoparticles which have a resonance absorption peak around 514 nm. The gold nanoparticles are dispersed on the surface of the MoS2 samples by means of spin-coating. Then, we measure the photoluminescence (PL) of the monolayer, bilayer and multilayer samples before and after the spin-coating, and find a great enhancement in the PL intensity of the monolayer sample. Also the PL intensities of bi-layer and multiple layer MoS2 samples are slightly enhanced. Our work shows that gold nanoparticles may impose an obvious p-doping effect to the monolayer and bi-layer MoS2 samples to enhance the PL, and a surface plasmon polariton effect of the gold nanoparticles is also a positive factor for the enhancement.

Plasmonic hot-electron assisted phase transformation in 2D-MoS2 for the hydrogen evolution reaction: current status and future prospects

“…128–130 Efficient electron transfer from metal nanoparticles to 2H-MoS 2 requires the formation of an interface between metal and MoS 2 . For fabrication of metals (Au, Ag, transient metals, metal alloys)/2H-MoS 2 hybrids, various synthesis techniques have been reported such as spin coating, 131 drop casting, 132 PAA template assisted electrodeposition, 133 intercalation of plasmonic metals, 134 doping of metals, 135 self-assembly of metal nanoparticles on the MoS 2 surface, 136 femtosecond pulse irritation synthesis, 137 and chemical integration of metal nanoparticles with MoS 2 . 138…”

Second harmonic generation of metal nanoparticles under tightly focused illumination

“…Under the electric dipolar approximation, SHG can only be observed at the surface of metal nanoparticles, which is usually described by a sheet of nonlinear polarization induced by the excitation field at the fundamental frequency. The surface nonlinear polarization can be expressed as [21] 𝑃 (𝑟 s , 2ω) = 𝜒 s : 𝐸(𝑟 s , ω)𝐸(𝑟 s , ω)δ (𝑟 s − h(𝑟 s )), (3) where 𝜒 (2) s is the surface second-order susceptibility tensor, h(𝑟 s ) denotes the surface of the spherical particle, which implies that there is a surface dipole sheet because the symmetry of the bulk is broken at the surface of the particle. The surface is assumed to be locally flat.…”

“…Owing to the outstanding localized surface plasmon (LSP) resonance [1] leading to field localization and enhancement, metal nanoparticles can exhibit unique optical properties and have received great interest in the last decade. [2] Due to various applications, such as subwavelength emitters in highresolution microscopy, [3] particle sizing, [4] and optical indicators for diagnostic purposes in medicine and biology, [5] metal nanoparticles are very necessary to thoroughly understand the interaction of focused beam with metal nanoparticles, especially after the incident beam is tightly focused by a high numerical aperture (NA) objective. Recently metal nanoparticles with various materials and shapes excited by highly focused beams have been investigated.…”

Preparation and the Photoluminescence Properties of Er³⁺-Doped MoS₂ Thin Films

“…The Er: MoS 2 film (sample 4) shown in Fig.2(b) is a large fluctuation film, and its average thickness is about 50 nm. For the same fabricate conditions, the thickness of the Er: MoS 2 film increases remarkably resulting from the catalytic action of Er 3+[9,10]. And rough surface benefits the absorption and emission of light.…”