Determining the impact of hydrofluoric acid on surface states of as-prepared and chemically modified Si nanocrystals

Abstract

Introduction of hydrofluoric acid before and during chemical functionalization of silicon nanocrystals with hydrocarbon chains is found to be very efficient for removing original surface defects of the nanocrystals as well as for preserving them from oxidation induced defects appearing on their surface during photoinitiated hydrosilylation procedure. In consequence, stable sols of highly luminescent silicon quantum dots in organic solvents with photoluminescence quantum yield up to 20% are shown to be easily obtained. Moreover, our approach allows considerable improvement of electric transport through meso-porous silicon nanostructures which is still a serious challenge for their applications in photovoltaics and thermoelectrics. Finally, the use of hydrofluoric acid appears as a cheap and efficient alternative to development of painstaking procedures and set-ups preventing oxidation induced deterioration of physico-chemical properties of the individual and interconnected silicon nanocrystals during their chemical functionalization.