Applications of colloidal inorganic nanoparticles: from medicine to energy

The synthesis of well-defined inorganic nanoparticles in colloidal solution, which evolved gradually from the 1950s onward, has now reached the point where applications in both the research world and the wider world can be realized. This Perspective explores some of the successes and still-remaining challenges in nanoparticle synthesis and ligand analysis, highlights selected work in the areas of biomedicine and energy conversion that are enabled by colloidal nanomaterials, and discusses technical barriers that need to be overcome by chemists and other scientists in order for nanotechnology to achieve its promise.