Applications of Monolayer‐Functionalized H‐Terminated Silicon Surfaces: A Review

Abstract

Silicon is an attractive semiconductor material for wide‐ranging applications, from electronics and sensing to solar cells. Functionalization of H‐terminated silicon surfaces with molecular monolayers can be used to tune the properties of the material toward a desired application. Several applications require the removal of the, often insulating, silicon oxide between the silicon surface and a monolayer, thus precluding the more conventional silane‐based chemistry. Here, the applications of monolayer‐functionalized silicon surfaces are surveyed starting from H‐terminated silicon. The oxide‐free routes available for Si–C, Si–N, Si–O–C, and Si–S bond formation are described, of which the most commonly used techniques include hydrosilylation and a chlorination/alkylation route onto H‐terminated silicon. Applications are subdivided into the areas of surface passivation, electronics, doping, optics, biomedical devices, and sensors. Overall, these methods provide great prospects for the development of stabilized silicon micro‐/nanosystems with engineered functionalities.

Computational Approaches to Photoelectrode Design through Molecular Functionalization for Enhanced Photoelectrochemical Water Splitting

“…To address the gap between extensive experimental reviews and studies on functionalized photoelectrodes and the far fewer theoretical reviews, this Minireview summarizes recent computational research on functionalized photoelectrodes for solar water splitting. We focus on the use of first‐principles modeling (DFT and MD) and device modeling to understand and predict the effect of organic monolayers on the photoelectrode: a) stability against photocorrosion (Section 2), b) charge separation through barrier height tuning (Section 3), and c) catalytic activity (Section 4).…”

Click Coupling Reactions on Flat and Nanostructured Hydrogen‐Passivated Silicon Surfaces

“…Among the many protocols available for surface functionalization of silicon substrate, chemical modification of hydrogen passivated silicon surfaces with unsaturated hydrocarbons has attracted intense interest in the last decade . In contrast to state‐of‐the‐art silane chemistry that requires an oxide layer between the silicon substrate and the organic monolayer, H‐terminated silicon surfaces are capable to form strong SiC bonds that may both facilitate the interaction between the silicon substrate and the environment as well as allow the formation of robust monolayers …”

“…Hydrosilylation reactions between alkynes and H‐terminated silicon surfaces have appeared to be a reliable strategy for SiC bond formation and surface functionalization and a large variety of applications have been reported in the last decade …”

“…[13] Among the many protocols available for surface functionalization of silicon substrate, chemical modification of hydrogen passivated silicon surfaces with unsaturated hydrocarbons has attracted intense interest in the last decade. [14,17] In contrast to state-of-the-art silane chemistry that requires an oxide layer between the silicon substrate and the organic monolayer, [18] H-terminated silicon surfaces are capable to form strong SiC bonds that may both facilitate the interaction between the silicon substrate and the environment as well as allow the formation of robust monolayers. [15] Hydrosilylation reactions between alkynes and H-terminated silicon surfaces have appeared to be a reliable strategy for SiC bond formation and surface functionalization and a large variety of applications have been reported in the last decade.…”

“…[15] Hydrosilylation reactions between alkynes and H-terminated silicon surfaces have appeared to be a reliable strategy for SiC bond formation and surface functionalization and a large variety of applications have been reported in the last decade. [17] Due to harsh reaction conditions and unwanted side reactions, only a limited number of functional groups are compatible with a hydrosilylation reaction. Thus, surface functionalities are often introduced in a two-step attachment procedure where a primer linker is first covalently grafted to the surface via hydrosilylation and the desired functionality is subsequently attached via a surface coupling reaction.…”