Plasmon-Induced Energy Transfer and Photoluminescence Manipulation in MoS₂ with a Different Number of Layers

Abstract

Monolayer or few-layer molybdenum disulfide (MoS 2 ) with intriguing physical properties enables a wide range of applications such as photocatalysis and photodetection. The controllable light−matter interaction in MoS 2 nanoflakes with different numbers of layers is critical for developing new optoelectronic functionalities. Recently, plasmonic nanostructures have been used to obtain strong near-field enhancement for the effective photoluminescence (PL) manipulation of MoS 2 . However, it is still unclear whether the PL manipulation is dominated by electron injection processes or the strong field induced Purcell effect so far. Here, we investigate the PL manipulation of MoS 2 nanoflakes with different numbers of layers using Au nanoparticles with different aggregate states. Combining the measured PL and scattering spectra, the Kelvin probe force microscopy images at the single-particle level, and the numerical simulations, we figure out how the electron injection and strong field enhancement contribute to the PL manipulation and why PL quenching occurs in few-layer flakes but PL enhancement occurs in thicker flakes. These findings would give us a greater understanding of the interaction between two-dimensional materials and plasmonic nanostructures.

Photoluminescence enhancement of monolayer MoS2 using plasmonic gallium nanoparticles

“…This approach has been the most common used in the literature with Au and Ag nanomaterials. They can be deposited by a chemical 8,20,21 or physical method 22,24,54 but the EF has not been higher than 6.5 except for e-beam lithography Ag NPs whose obtained maximum EF was 12.5. 22 Thus, despite Ga being among the so-called poor metals which, in principle, have worse plasmonic properties than noble metals such as Au and Ag, especially in the VIS range, we have obtained an EF in the same order or even higher than the literature with a metallic material (Ga) which supposedly has its best plasmonic performance in the UV region.…”

“…In fact, plasmonics and 2D materials have been actively investigated during the last few years. [16][17][18] However, until now, only silver (Ag) and gold (Au) NPs have been used for the PL enhancement of MoS 2 8,[18][19][20][21][22][23][24] due to their low losses in the VIS range 25,26 compared to the so-called poor metals that have their main activity in the ultraviolet (UV) region such as aluminum (Al), magnesium (Mg), rhodium (Rh), indium (In) and gallium (Ga). 27 In particular, Ga has been previously shown to facilitate light-matter interaction in a wide variety of applications such as biosensors, 28,29 solid-liquid phase-change memories, 30 waveguiding 31 and surface enhanced Raman scattering (SERS) in the VIS 32 and the UV 33 region.…”

Enhanced Photocarrier Generation with Selectable Wavelengths by M‐Decorated‐CuInS2 Nanocrystals (M = Au and Pt) Synthesized in a Single Surfactant Process on MoS2 Bilayers

“…Previous works have revealed the enhanced electromagnetic field and the light confinement effect by combining plasmonic metal nanostructures and 2D‐based photodetectors, leading to the improvement of the light absorption under the visible spectral region . Also, by applying metal particles with diverse morphologies such as nanoparticles, nanotubes/nanowires, nanodiscs, core–shell particles and creating nanoarray patterns, the resonance wavelength can be tunable. To achieve the better performance of photodetector on the MoS 2 layered material, we aim to combine highly absorptive CuInS 2 (CIS) nanoparticles with noble metal nanoparticles as the photosensitizer to enhance the intrinsic absorptivity of noble metal nanocrystals.…”

Robust B-exciton emission at room temperature in few-layers of MoS2:Ag nanoheterojunctions embedded into a glass matrix

“…As a reference, we first measured the intrinsic PL spectra of MoS 2 flakes deposited on Si substrates, using excitation energy of 2.28 eV (543 nm); considering that the direct excitonic transition is weakened with increasing the layer number in MoS 2 , a broad emission peak with weak intensity was observed (Fig. S4) 18,39 . It is notable that the MoS 2 spectrum has been dramatically changed upon its incorporation in AgPO 3 .…”