FUNCTIONALIZATION AND CHARACTERIZATION OF TUNGSTEN DISULFIDE WITH 2-AMINOETHANETHIOL

Restricted (Penn State Only)
Author:
Jinandra, Amisha Madhu
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 31, 2017
Committee Members:
  • Mauricio Terrones Maldonado, Thesis Advisor
  • Raymond Edward Schaak, Committee Member
  • Joshua Alexander Robinson, Committee Member
Keywords:
  • Two-dimensional materials
  • chemical functionalization
  • thiol
  • chemistry
  • ws2
  • tmd
  • transition metal dichalcogenide
  • 2-aminoethanethiol
  • Raman Spectroscopy
  • AFM
  • SEM
  • ToF-SIMS
  • XPS
  • Physisorption
  • layered material
Abstract:
Two-dimensional (2D) layered transition-metal dichalcogenides (TMDs) are an emerging, fascinating class of nanomaterial with a wide range of potential applications including catalysis, electronics, photonics, energy storage, and sensing. Although, highly crystalline TMDs are considered challenging to functionalize, owing to their inert nature. This work demonstrates that mono-layered or few-layered chemical vapor deposition (CVD) grown Tungsten Disulfide (H phase- WS2) can be functionalized via aerosolized thiolated ligands such as 2-Aminoethanethiol (NH2CH2CH2SH). The TMD materials were characterized before and after exposure to these ligands using Optical Microscopy, Fluorescence Microscopy, Raman Spectroscopy, Atomic Force Microscopy (AFM), X- ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Adsorption of the sulfur bearing molecules on the surface of the 2H- WS2, with some selectivity relative to defective regions, was noted. However, it was determined that the thiol functional group was reduced on the surface to form a disulfide. This method of surface functionalization of 2D WS2 may provide an ideal platform in which the interaction between ligands and the 2D-TMDs may be used as selective anchoring sites that could result in the synthesis of novel functional materials.