Unsaturated organic monolayers on silicon: Surface passivation and reactivity

Silicon nanostructures are promising materials for inclusion into inexpensive, yet efficient, solar cells. Surface passivation becomes increasingly important in such structures, and these designs may require chemical linking of silicon interfaces. To address these concerns, a means of passivating silicon surfaces using small, unsaturated organic moieties has been developed and applied to model silicon (111) surfaces. These monolayers protect the surface from oxidation while eliminating interfacial trap states that induce the recombination of photo-induced charge carriers. In addition, these organic groups can undergo secondary reactions, allowing chemical elaboration of the surface while maintaining a passivating underlayer. Here we discuss the passivating properties of unsaturated groups bound to the silicon surface, including vinyl and allyl groups, and we explore their use in metal-catalyzed coupling reactions commonly employed with solution-phase olefins.