Micropatterned Ferrocenyl Monolayers Covalently Bound to Hydrogen-Terminated Silicon Surfaces: Effects of Pattern Size on the Cyclic Voltammetry and Capacitance Characteristics

• Published in: Langmuir Vol. 30; no. 24; pp. 7235 - 7243
• Main Authors: Fabre, Bruno, Pujari, Sidharam P, Scheres, Luc, Zuilhof, Han
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.06.2014
• Subjects: charge-storage; Chemical Sciences; click chemistry; gold; information-storage; molecular monolayers; Organic chemistry; organic monolayers; oxide-free silicon; self-assembled monolayers; si surfaces
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la501330j

The effect of the size of patterns of micropatterned ferrocene (Fc)-functionalized, oxide-free n-type Si(111) surfaces was systematically investigated by electrochemical methods. Microcontact printing with amine-functionalized Fc derivatives was performed on a homogeneous acid fluoride-terminated alkenyl monolayer covalently bound to n-type H-terminated Si surfaces to give Fc patterns of different sizes (5 × 5, 10 × 10, and 20 × 20 μm2), followed by backfilling with n-butylamine. These Fc-micropatterned surfaces were characterized by static water contact angle measurements, ellipsometry, X-ray photoelectron spectroscopy (XPS), infrared reflection–absorption spectroscopy (IRRAS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The charge-transfer process between the Fc-micropatterned and underlying Si interface was subsequently studied by cyclic voltammetry and capacitance. By electrochemical studies, it is evident that the smallest electroactive ferrocenyl patterns (i.e., 5 × 5 μm2 squares) show ideal surface electrochemistry, which is characterized by narrow, perfectly symmetric, and intense cyclic voltammetry and capacitance peaks. In this respect, strategies are briefly discussed to further improve the development of photoswitchable charge storage microcells using the produced redox-active monolayers.