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.