Room temperature sonochemically-initiated dehydrogenative coupling of silanes on silicon nanoparticle surfaces

Dehydrogenative coupling provides a convenient approach for forming Si-Si bonds in molecular systems and on silicon surfaces. Most procedures require the use of transition metal catalysts, which can limit adoption due to cost and contamination - this is particularly true when considering silicon nanoparticles (SiNPs). We demonstrate a catalyst-free method that uses an ultrasonication bath and a radical initiator to drive the dehydrocoupling reaction forward at room temperature to functionalize SiNP surfaces. This approach is tolerant of all types of silanes tested, including primary alkyl and aryl, secondary, and tertiary silanes, and provides comparable reactivity to standard catalyzed systems (i.e., surface coverages of ∼10%) while maintaining SiNP photoluminescence response. To our surprise, this new functionalization approach is the first reported approach that provides controlled synthesis of amorphous SiNPs.