Date of Award
Spring 2026
Document Type
Open Access Dissertation
Department
Chemistry and Biochemistry
First Advisor
Aaron K. Vannucci
Abstract
Solar-to-chemical energy conversion is a promising approach for storing renewable energy in chemical bonds. However, efficient photoelectrochemical systems require long-lived charge separation and stable interfaces between molecular components and electrode surfaces. This dissertation explores strategies to control excited-state reactivity, exploit new molecule-oxide attachments, and enable charge separation at functionalized electrodes.
Chapter 2 investigates light-driven hydrogen generation using the excited-state behavior of 7-bromonaphthol in the presence of ferrocene. Spectroscopic measurements confirm ferrocenium formation during irradiation, and gas chromatography verifies H2 production in acetonitrile. This chemistry is further translated to photoelectrochemical conditions using ferrocene-modified carbon electrodes, which display enhanced photocurrent at mild applied potentials compared to unmodified electrodes. These results demonstrate that excited-state weak acids can support hydrogen formation using simple molecular components.
Chapter 3 develops a new covalent metal–oxide ester (MOx–ester) motif to attach a Ru(II) polypyridyl photosensitizer to TiO2 and compares it directly to a traditional carboxylate bound analogue. Characterization by cyclic voltammetry, UV–Vis spectroscopy, solid-state 13C NMR, and FTIR-ATR confirms successful surface attachment. The ester anchoring provides improved stability and higher surface loading in acetonitrile while altering interfacial charge-transfer properties relative to a carboxylate-bound system.
Chapter 4 transitions to electrocatalysis by examining Cu(I) molecular complexes immobilized on nanostructured ITO electrodes. Electrochemical measurements show that surface confinement modifies the Cu(I/II) redox behavior compared to solution, indicating that the molecule-oxide interface influences electron-transfer kinetics and suppresses structural reorganization. These results support the concept of interfacial geometric constraint (entatic-state-like behavior) as a strategy to control redox properties and enhance catalytic function.
Overall, this dissertation highlights interfacial design as a unifying strategy for improving stability and charge control in hybrid molecular-oxide systems, advancing the development of durable platforms for light-driven and electro-driven chemical transformations.
Rights
© 2026, Sachini C.D. Dissanayake Mudiyanselage
Recommended Citation
Dissanayake Mudiyanselage, S. C.(2026). Interfacial Design Strategies for Long-lived Charge Separation and Catalysis in Molecular and Hybrid Photoelectrochemical Systems. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8921