Photophysics of Strongly Confined Multiexcitons from the Perspective of Lasing and Solar Energy Conversion

Using semiconductor nanocrystals one can produce extremely strong spatial confinement of electronic wave functions not accessible with other types of nanostructures. One consequence of this effect is a significant enhancement in carrier-carrier interactions that lead to a number of novel physical phenomena including ultrafast mutiexciton decay due to Auger recombination and efficient generation of multiple electron-hole pairs by single photons via carrier multiplication. In this talk, I will discuss the implications of ultrafast Auger decay for lasing applications of the nanocrystals and describe several recent approaches developed in our group for resolving this problem by engineering carrier-carrier interactions in various types of heterostructured particles. I will also review the current status of carrier-multiplication research including experimental challenges in studies of this phenomenon, the role of extraneous effects, the competing energy relaxation channels, and applications of carrier multiplication in solar photovoltaics.