Xiaoting Zhang, a doctoral candidate in chemistry, will defend their dissertation titled “Epitaxial Growth of Metal-Organic Framework Thin Films by Electro-Conversion and Electrodeposition.” Their advisor, Dr. Jay Switzer, is a curators’ distinguished professor emeritus in the chemistry department. The dissertation abstract is provided below.

Electrochemical epitaxy is a facile and inexpensive soft-solution process to fabricate highly ordered thin films. This research focuses on the epitaxial growth of metal-organic framework (MOF) thin films by electrochemical methods which include electro-conversion and electrodeposition.

First, an electrochemical conversion pathway was invented to achieve epitaxial MOF thin films. Epitaxial single-domain Cu-BTC(111) thin films were manufactured by electrochemical oxidation of Cu₂O(111) films electrodeposited on single-crystal Au(111). The single-crystal-like Cu-BTC(111) thin films with out-of-plane and in-plane order provide well-aligned 3.5 Å triangular windows along the [111] direction. Cu-BTC(111) foils were fabricated from the Cu-BTC/Cu₂O system by electrochemical etching and epitaxial lift-off. Epitaxial two-domain Cu-BTC(111) films and textured Cu-BTC(111) films were produced by using low-cost and highly scalable substrates, Au on Si and Au on glass, respectively.

Second, a direct electrodeposition strategy was developed to attain epitaxial MOF thin films. Epitaxial Cu-BTC(100) thin films were electrodeposited from a water/ethanol solution on single-crystal Au(100). Epitaxial Cu-BTC(111) thin films were also electrodeposited on single-crystal Au(111) with Cu₂O as a buffer layer. The single-crystal-like Cu-BTC(100) thin films without-of-plane and in-plane order provide well-aligned 9 Å square windows along the [100] direction. The single-crystal-like Cu-BTC(111) thin films with out-of-plane and in-plane order provide well-aligned 3.5 Å triangular windows along the [111] direction.