The Complex Interaction of Spectroscopic Shifts and Electronic Properties in Semiconductor Nanocrystal Films

Absorption spectroscopy has traditionally served as a powerful technique for the study of solution synthesized semiconductor nanocrystals, enabling information on the size, dispersity, concentration, and overall quality of a sample to be obtained quickly and easily. When thin, densely packed films of these materials are produced through ligand exchange, spectroscopic shifts to both higher and lower energy are observed. Reduction of the internanocrystal distance can result in both a change to the overall dielectric constant of the film as well as increased electronic coupling, producing a redshift. At the same time, surface oxidation has the effect of increasing the confinement, producing a blueshift. This Perspective focuses on PbSe, a material of current interest, and the potential for correlating these spectroscopic shifts to optoelectronic properties, highlighting both recent work in the literature and areas in need of additional study.