Long-Range Uniaxial Alignment of Polyaromatics and Polybisnorbornenes: Preparation Methodology and Characterization by Scanning Probe Microscopy
Date Issued
2009
Date
2009
Author(s)
Lee, Shern-Long
Abstract
To develop new methods for the preparation of thin-films for molecular electronics application is the major goal of this dissertation. We report the assembly of polyaromatic monolayers that exhibit predominantly one single-domain up to 7 mm by planar Couette-like flow whose anisotropic shear induces an edge-on orientation for 3,6,11,14-tetradodecyloxydibenzo[g,p]chrysene ((C12O)4DBC)1 and coronene which would otherwise adapt the face-on arrangement on graphite surface. Due to electrons can move freely through the packed molecules, the thin-film hence can be considered as a good pathway for electron transfer. In addition, with a shear treatment for dropcast films, a unidirectionally ordered domain of double Stranded Oligobisnorbornene with a defect density less than 0.5% can be prepared. Simulation results by molecular dynamics suggest that there may be multiple interactions such as pi-pi stacking and dipolar attractions taking place between the termini of the oligomers. canning tunneling microscopy (STM) and atomic force microscopy (AFM) are major approaches in this dissertation used to analyze molecular orientations before and after being subjected to shear treatments. We also investigate optical properties of the prepared thin-films and perform STS measurements for the discussion of molecular adsorptions as well as the variety of energetic levels of molecules.
Subjects
Scanning Probe Microscopy
alignment
molecular self-assembly
Type
thesis
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