Synthesis and characterisation of MoS2 - NaYF4:Yb, Er nanocomposite

• Main Author: Ann, Kai Heng
• Other Authors: Alfred Tok Iing Yoong
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Nanotechnology; DRNTU::Engineering::Materials::Composite materials; DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: http://hdl.handle.net/10356/55858
• Institution: Nanyang Technological University

MoS2 is a transition metal dichalcogenide with a structure analogous to graphene and has been extensively researched and applied in various areas. However due to low absorption of in the infrared region, there are limitations for its applications. In this report, a novel MoS2- NaYF4: Yb, Er nanocomposite is synthesized using a simple one pot decomposition method. This nanocomposite takes advantage of the upconversion process to extend the absorption spectrum to the NIR range. The morphology and properties of the nanocomposite were analysed using TEM, XRD, FTIR, UV-Vis and luminescence spectroscopy. The results indicate that MoS2 and the UCNPs have fused together to form a nanocomposite with its surface capped with oleic acid and oleylamine. However, the UCNPs showed slight aggregation, and there is a significant distribution of MoS2 nanosheet sizes. The UV-Vis absorption spectrum of the nanocomposite did not change significantly but the luminescence spectrum proved that upconverted infrared light by UCNPs can be absorbed by the MoS2 in the nanocomposite and thereby enhancing its absorption range. As visible and NIR light make up a huge percentage of solar energy, this material can potentially be used in applications such as light harvesting, photocatalysis, bio-imaging and IR photodetection.