Single Nanostructure Visible and Infrared Microscopies

There has been three decades of work on applying single particle emission spectroscopy to semiconductor nanostructures. This technique has proven immensely useful towards uncovering novel photophysics of these systems, normally hidden due to ensemble averaging. However, despite valuable knowledge gleaned, the limitations of single particle emission spectroscopy are now becoming apparent. First and foremost, photoluminescence is not a universal phenomenon, immediately restricting the applicability of this technique to only limited families of nanomaterials. Second, surface defects, and resonant or non-resonant Stokes shifts can complicate interpretations from emission spectra. Finally, photoluminescence offers no insight into the excited state progression of a nanostructure’s electronic structure.

Single particle extinction spectroscopy is an immediate solution towards overcoming these shortcomings. This thesis explains why these measurements are inherently challenging and briefly discusses two of the most popular approaches towards detecting a single nanostructure’s extinction. Next, it describes the greater understanding of one-dimensional cadmium selenide nanostructures, i.e. nanowires and nanorods, derived from these measurements. Finally, it describes a future extension of single particle extinction measurements to the infrared spectrum and discusses the application of infrared microscopies to novel photovoltaic perovskite materials.