Nanoparticle Scaffolds for Devices and Sensors

Modified metal and semiconductor nanoparticles have become the subject of an extremely active field of chemical research in the last few years. This widespread interest is understandable considering the proliferation of simple chemical methods for the preparation of metal and semiconductor particles with sizes in the range 1–100 nm, 1 which is of great interest in emerging nanotechnologies. The properties of metal and semiconductor nanoparticles in this size range differ from those of the corresponding bulk materials and approach the molecular limit.2 For the smallest nanoparticles, the distribution of electronic states departs from the usual band structure and discrete states will appear at the band edges. Electrons may undergo quantum confinement and these systems may exhibit unique electronic, magnetic and optical properties associated with the socalled quantum dots. Furthermore, as the size of the nanoparticle decreases, a larger fraction of the constituent atoms are located on its surface. This is particularly important when dealing with metals with applications in catalysis, because of the high cost associated with these materials.