Semiconductor nanocrystals in sol-gel derived matrices

Wet-chemically synthesized colloidal semiconductor nanocrystals are unique chromophores which possess properties such as size-dependent absorption and emission, large action cross-sections and flexible surface chemistry. This Perspective summarizes efforts in the field to incorporate these nanocrystals into sol-gel derived matrices, thereby harnessing their salient material properties to enhance or create new avenues for research in applications such as biological imaging, diagnostics and optical amplifiers. A description of the basic chemistry involved in making the semiconductor nanocrystals compatible with the sol-gel process is given, as well as the different strategies developed to localize various types of nanocrystals within the sol-gel network. As the field of semiconductor nanocrystals evolves towards structurally complex multifunctional architectures, the physicochemical attributes of composites of nanocrystals in sol-gel matrices are also dramatically improved. A number of examples from the most recent reports on such structures will be highlighted, along with a brief discussion on the future outlook of such materials.