Date of Award

Fall 2026

Abstract

ABSTRACTDiPy-Acenes: A New Family of Air-Stable, Water-Soluble, Small Molecule Organic Semiconductors

By Linda N. Phan University of New Hampshire, July 2026 This thesis describes a new class of acene derivative called DiPy-Acenes, short for dipyridinium acenes. DiPy-Acenes are air stable, water soluble dications composed of an acene core that is covalently attached to two separate pyridinium ions. A series of DiPy-Acenes containing naphthalene, anthracene, tetracene, and pentacene cores were studied both computationally (density functional theory calculations) and experimentally. Synthesized compounds were characterized using NMR spectroscopy, high-resolution mass spectrometry, UV-visible spectroscopy, and fluorescence spectroscopy. The electron-deficient pyridinium groups reduce the HOMO and LUMO energy levels of DiPy-Acenes compared to unsubstituted acenes while their associated HOMO-LUMO gaps, Eg, remain relatively unchanged. The reduction in HOMO energy levels renders DiPy-Acenes unreactive with ambient oxygen in both solution phases and in the solid-state. The reduction in LUMO energies is significant but not large enough to convert them to N-type organic semiconductors. The ionic nature of DiPy-Acenes make them water soluble where they persist indefinitely without hydrolysis or dealkylation. Traditional organic semiconductors require toxic, volatile organic solvents like chlorobenzene, chloroform, or dichlorobenzene for solubility and thin-film device fabrication. Transitioning to water-soluble alternatives like DiPy-Acenes can reduce halogenated hydrocarbon emissions during device fabrication, and should allow for deposition directly on top of standard hydrophobic organic layers without damage. DiPy-Acenes also seem ideally suited for emerging bioelectronic applications. Their water solubility should enable interface with living tissues, cells, or proteins without chemical toxicity or denaturation from leftover organic solvent. Their ionic nature supports mixed ionic-electronic conduction, potentially transporting both electrons/holes and biological ions of interest.

Document Type

Master's Thesis

First Advisor

Glen P Miller

Second Advisor

Erik Berda

Third Advisor

Charles Zercher

Department or Program

Chemistry

Degree Name

Master of Science

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