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 quantumyield and used as fluorescent biological labels.