Photochemical grafting and patterning of organic monolayers on indium tin oxide substrates

Covalently attached organic layers on indium tin oxide (ITO) surfaces were prepared by the photochemical grafting with 1-alkenes. The surface modification was monitored with static water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. Hydrophobic methyl-terminated ITO surfaces can be obtained via the grafting of tetradec-1-ene, whereas the attachment of ω-functionalized 1-alkenes leads to functionalized ITO surfaces. The use of a C≡C-Ge(CH(3))(3) terminus allows for facile tagging of the surface with an azido group via a one-pot deprotection/click reaction, resulting in bio/electronically active interfaces. The combination of nonaggressive chemicals (alkenes), mild reaction conditions (room temperature), and a light-induced grafting that facilitates the direct patterning of organic layers makes this simple approach highly promising for the development of ITO-based (bio)electronic devices.