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Date Permissions Signed

3-8-2021

Date of Award

Winter 2021

Document Type

Masters Thesis

Department or Program Affiliation

Chemistry

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Patrick, David L.

Second Advisor

Johnson, Brad L., 1961-

Third Advisor

Kowalczyk, Tim

Abstract

The advancement of semiconducting materials is paramount to the future of electronics. Organic semiconducting materials are of particular interest due to their significantly lower processing cost compared to traditional inorganic semiconducting materials, such as silicon. However, the present toolkit for solution-based controlled growth of polycrystalline thin films is lacking. Therefore, the purpose of this research is to build such a toolkit, wherein tunable parameter relationships of organic thin-film growth are evaluated and compared both experimentally and computationally. A multi-scale model has been developed, which combines mean field rate equations with a self-consistent treatment of the critical stable monomer cluster size, and a stochastic treatment of nucleation once beyond the critical monomer concentration. The result of the simulation is a 2D monomer concentration landscape and a map of crystal locations; the evolution of each component can be viewed over the time span of the experiment. Using bright-field fluorescence video-microscopy, the same information is obtained experimentally. Computational and experimental spacing statistics, radial monomer concentrations, and parameter relationships are explored using these methods. Understanding these factors will further our ability to understand fundamental parameter relationships of OVLS (organic-vapor-liquid-solid) deposition, polycrystalline thin-film nucleation and the ability to predict optimal parameters for thin-film architectural growth patterns; one such example being shape engineering crystals to grow in holey patterns for novel applications, such as photonics. Furthermore, a phototransistor, fabricated using the OVLS deposition scheme, is characterized and compared to a recently-published and structurally-similar device.

Type

Text

Keywords

organic crystal nucleation, monomer concentration landscape, multi-scale model, burst nucleation, nucleation in solvent, controlled crystal growth, phototransistor

Publisher

Western Washington University

OCLC Number

1241198004

Subject – LCSH

Nucleation; Organic semiconductors; Polycrystals; Multiscale modeling

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

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