Silicon nanoparticle based fluorescent biological label via low temperature thermal degradation of chloroalkylsilane

A simple low temperature colloid-chemical synthetic method is reported for size controlled synthesis of hydrophobic silicon nanoparticles in the 1–10 nm range. These silicon nanoparticles show size dependent tunable visible emission from blue to red with fluorescence quantum yield in the range of 6–13%. These silicon nanoparticles can be subjected to extensive surface chemistry without significant loss of their fluorescence properties. The as-synthesized red emitting nanoparticles have been transformed into water soluble functional nanoprobes of 18 nm hydrodynamic diameter and 5% fluorescence quantum yield and used as fluorescent biological labels.