Highly ordered, covalently attached organic layers represent a viable route to chemically glue dissimilar materials for solar energy conversion and other electronic applications. We functionalized chemically oxidized Si(111) and TiO2 surfaces with covalently attached rylene molecules and demonstrated further chemical conversion of the attached species. Base-catalyzed activation of perylene tetracarboxylic dianhydride (PTCDA) preceded reaction with phenylaminosilane-terminated surfaces yielding surface-bound perylene via an imide linkage. Transflection infrared spectroscopy and X-ray photoelectron spectrscopy (XPS) elucidated attachment modes and coverages, respectively. Overlayer model interpretation of the photoelectron results determined perylene surface coverage of ~15% relative to the surface density of Si(111) atop sites, and a ~10% surface coverage of imide-terminated perylene species. We discuss the present results in terms of possible coverage and packing on oxide-free silicon surfaces, the utilization of covalently attached rylene species as electron-transporting and hole-blocking connecting layers in molecular electronics and tandem-junction photovoltaic (PV) designs.

Covalent attachment and characterization of perylene monolayers on Si(111) and TiO2 for electron-selective carrier transport in tandem-junction PV

2019 Fall National Meeting

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