Award Date

8-1-2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

First Committee Member

Dong-Chan Lee

Second Committee Member

Jun Yong Kang

Third Committee Member

Kathleen Robins

Fourth Committee Member

Jaeyun Moon

Number of Pages

200

Abstract

π-Conjugated systems have been receiving notable attention in the field of organic material chemistry due to their interesting optical properties, assembling properties, and potential application in optoelectronics. Among various self-assembly methods, organogelation has been known to allow facile and easily reproducible molecular assembly. This work focuses on creating new π-organogelators with various side group modifications which in result allow proper tuning of the optical properties along with an effective self-assembly upon gelation. The research comprises of two chapters: 1) the first chapter focuses on N-heteroacenes (NHAs) with gelation property and 2) the second chapter investigates gelation induced phosphorescence (GIP) of purely organic compounds. The NHA synthesis has been facing obstacles in active research due to low stability, poor solubility, and lengthy synthetic procedures. Also, main modification route has been linear modification through length extension. This study has discovered two-dimensionally modified NHA with axial side group incorporation with optimum synthesis route. We explored comprehensive synthetic approaches to axially substituted NHA based nanoribbon with 11 linearly annulated rings. Even with the large π-core, the axial functionalization imparted not only processability but also one-dimensional self-assembly capability via organogelation while maintaining excellent thermal stability. For the GIP chapter, we explored benzil (BZL) derivative-based all-organic phosphors which exhibited phosphorescence upon self-assembly through gelation. Through simple side group variation, tuning of phosphorescence performance was possible, which allow improved quantum efficiency without sacrificing lifetime at room temperature. Also, while most room-temperature phosphorescence (RTP) materials show phosphorescence emission only under stringent conditions such as crystallization, this research demonstrated the efficacy of organogelation as a new processing method to replace commonly utilized crystallization. As shown in this work, appropriate side group tuning to endow π-conjugated molecules with gelation properties would be potentially useful for wide range of future optoelectronic applications.

Keywords

Gelation induced phosphorescence; N-heteroacenes; Nanoribbon; Organogel; Polycyclic aromatic hydrocarbons; Room-temperature phosphorescence

Disciplines

Organic Chemistry

File Format

pdf

File Size

11000 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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