Nanoparticle clusters are described. In particular nanoparticle clusters formed from two or more individual nanoparticles of different types are described and methods for fabricating such nanoparticle clusters are further described. These nanoparticle clusters are fabricated by surface activating individual ones of the plurality of nanoparticles by desorption of surfactant molecules from the surface of the coated nanoparticles through exposure of the individual ones of the plurality of nanoparticles to an activating agent.
