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ACS Appl. Mater. Interfaces, 2018, 10 (15), pp 13211–13217

Interfacial Electron Transfer of Ferrocene Immobilized onto Indium Tin Oxide through Covalent and Noncovalent Interactions

Caitlin M. HannaChristopher D. SanbornShane Ardo , and Jenny Y. Yang* 

Department of Chemistry and Department of Chemical Engineering and Materials ScienceUniversity of CaliforniaIrvineCalifornia 
92697United States

ACS Appl. Mater. Interfaces201810 (15), pp 13211–13217, DOI: 10.1021/acsami.8b01219, Publication Date (Web): April 6, 2018

The immobilization of molecular species onto electrodes presents a direct route to modifying  surface properties with molecular fidelity. Conventional methods include direct covalent attachment and physisorption of pyrene-appended molecular compounds to electrodes with aromatic character through π–π interactions. A recently reported hybrid approach extends the synthetic flexibility of the latter to a broader range of electrode materials. We report an application of this approach to immobilization of pyrene-appended ferrocene onto pyrene-functionalized indium tin oxide (ITO). The modified ITO surfaces were characterized using X-ray photoelectron spectroscopy, fluorescence spectroscopy, and electrochemical techniques. An electron-transfer rate constant (kapp) of 100 ± 8 s–1 was measured between the electrode and immobilized ferrocene using electrochemical methods. For comparison, a ferrocene-modified electrode using conventional covalent attachment of vinylferrocene was also prepared, and kapp was measured to be 9 ± 2 s–1.