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

Abdus Salam Sarkar,George Kioseoglou,Efthymis Serpetzoglou,Emmanuel Stratakis,Ioannis Konidakis,Ioanna Demeridou

doi:10.1038/s41598-020-72899-3

Abdus Salam Sarkar, George Kioseoglou + Show 4 more

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https://doi.org/10.1038/s41598-020-72899-3

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Abstract

Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS2) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications. Although significant effort has been devoted towards enhancing or manipulating the excitonic emission in MoS2 monolayers, the excitonic emission in few-layers MoS2 has been largely unexplored. Here, we put forward a novel nano-heterojunction system, prepared with a non-lithographic process, to enhance and control such emission. It is based on the incorporation of few-layers MoS2 into a plasmonic silver metaphosphate glass (AgPO3) matrix. It is shown that, apart from the enhancement of the emission of both A- and B-excitons, the B-excitonic emission dominates the PL intensity. In particular, we observe an almost six-fold enhancement of the B-exciton emission, compared to control MoS2 samples. This enhanced PL at room temperature is attributed to an enhanced exciton–plasmon coupling and it is supported by ultrafast time-resolved spectroscopy that reveals plasmon-enhanced electron transfer that takes place in Ag nanoparticles-MoS2 nanoheterojunctions. Our results provide a great avenue to tailor the emission properties of few-layers MoS2, which could find application in emerging valleytronic devices working with B excitons.

Highlights

Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS2) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications
We present the development of a nanohybrid heterojunction system composed of few layers of MoS2 embedded into a silver metaphosphate glass (AgPO3), as a means to enhance and control the MoS2 exciton emission
We have obtained a six-fold enhancement factor for the intrinsically weak B exciton peak. Such enhancement factor for the B excitonic emission is explained with the help of dipole–dipole interaction via exciton–plasmon coupling

Summary

Introduction

Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS2) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications. We put forward a novel nano-heterojunction system, prepared with a non-lithographic process, to enhance and control such emission It is based on the incorporation of few-layers M oS2 into a plasmonic silver metaphosphate glass ( AgPO3) matrix. Few-layers MoS2, as an indirect semiconductor, have significantly larger optical density, which enhances its external quantum efficiency[17] Owing to this advantage, research on the PL properties in few layers M oS2 has received significant attention. We present the development of a nanohybrid heterojunction system composed of few layers of MoS2 embedded into a silver metaphosphate glass (AgPO3), as a means to enhance and control the MoS2 exciton emission. The presence of silver nanoparticles (NPs) within the glass matrix gives rise to interesting optical phenomena that can be exploited towards enhancing and manipulating the PL properties of the incorporated MoS2 layers. It is shown that the layered TMDs create nanoscale van der Waals heterojunctions with the metallic nanostructures of the glass, which can be exploited to tailor light-matter interactions at the nanoscale

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