Dataset Information

Formation of Brightly Luminescent MoS2 Nanoislands from Multilayer Flakes via Plasma Treatment and Laser Exposure.

ABSTRACT: A robust and reliable method for enhancing the photoluminescence (PL) of multilayer MoS2 is demonstrated using an oxygen plasma treatment process followed by laser exposure. Here, the plasma and laser treatments result in an indirect-to-direct band gap transition. The oxygen plasma creates a slight decoupling of the layers and converts some of the MoS2 to MoO3. Subsequent laser irradiation further oxidizes the MoS2 to MoO3, as confirmed via X-ray photoelectron spectroscopy, and results in localized regions of brightly luminescent MoS2 monolayer triangular islands as seen in high-resolution transmission electron microscopy images. The PL lifetimes are found to decrease from 494 to 190 ps after plasma and laser treatment, reflecting the smaller size of the MoS2 grains/regions. Atomic force microscopic imaging shows a 2 nm increase in thickness of the laser-irradiated regions, which provides further evidence of the MoS2 being converted to MoO3.

SUBMITTER: Wang B

PROVIDER: S-EPMC7439701 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Formation of Brightly Luminescent MoS2 Nanoislands from Multilayer Flakes via Plasma Treatment and Laser Exposure.

Wang Bo B Yang Sisi S Wang Yu Y Kim Younghee Y Htoon Han H Doorn Stephen K SK Foran Brendan J BJ Bushmaker Adam W AW Baker David R DR Forcherio Gregory T GT Cronin Stephen B SB

ACS omega 20200806 32

A robust and reliable method for enhancing the photoluminescence (PL) of multilayer MoS2 is demonstrated using an oxygen plasma treatment process followed by laser exposure. Here, the plasma and laser treatments result in an indirect-to-direct band gap transition. The oxygen plasma creates a slight decoupling of the layers and converts some of the MoS2 to MoO3. Subsequent laser irradiation further oxidizes the MoS2 to MoO3, as confirmed via ...[more]

PMID: 32832807

Similar Datasets

Project description:Tribological studies of the 2D nanoadditives such as MoS2 and graphene are mostly performed in base oils such as SN500, SN150, or paraffin. We have focused on their effect in lubrication properties of industrial oils (e.g., axle, transmission, and compressor oils) along with SN500 oil employing a four-ball tester. Two types of graphene powders (GpowA with fewer defects than GpowC), MoS2 powder, and their physical mixtures are chosen as nanoadditives. The tribology performance for 0.05 wt% of additives in various industrial oils is evaluated by monitoring the coefficient of friction (COF) during rubbing and wear scar diameter (WSD) of the steel balls after rubbing. Elemental analysis and electron microscopy have been performed on the wear surfaces for evidence of any tribofilm formation. GpowA favors antifriction for axle and transmission oils with 40% reduction in axle oil, whereas it improved antiwear properties in most of the oils. GpowC shows a COF decrement by 12% only for compressor oil, but contribute to wear reduction in all oils. The observed COF reduction is attributed to the compatibility of nonfunctionalized GpowA with nonpolar axle oil and functionalized GpowC with polar compressor oil. MoS2 shows a decrease in the COF and WSD in most industrial oils; the best being 60% COF and 7% WSD reduction in axle oil. For additives in oils that favor antiwear, flakes or particles are observed on the wear surface supported by the higher elemental contribution of the constituents from the wear region. The mixtures of GpowA or C with MoS2, however, does not seem to favor improvement in the COF or WSD in industrial oils. With assistance from oleylamine surfactants, the lubrication properties of most additives are improved, particularly for the mixtures with 12-15% COF reduction and 4-7% WSD reduction in compressor oil. The study indicates that a large sheet size of high-quality graphene aids antifriction and addition of surfactant molecules facilitates a co-operative effect between MoS2 and graphene for improved tribology.

Dataset Information

Formation of Brightly Luminescent MoS2 Nanoislands from Multilayer Flakes via Plasma Treatment and Laser Exposure.

Publications

Formation of Brightly Luminescent MoS<sub>2</sub> Nanoislands from Multilayer Flakes via Plasma Treatment and Laser Exposure.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets