Understanding and Exploiting the Interface of Semiconductor Nanocrystals for Light Emissive Applications

Semiconductor nanocrystals have been extensively studied for optoelectronic applications including light emission, the focus of this review. Historically, the core of the nanocrystal was the main aspect of the system as it gives rise to the confined excitons and multiexcitons which absorb and emit light. In addition to the core, the surface or interface of these nanocrystals is also important by virtue of their small size. Yet, our understanding of the surface is in its early stages in terms of both chemical and electronic structure. Here, we review the ways in which the interface can control the excitonics, which gives rise to optoelectronic function. We focus our discussion on the ways in which the interface can control optical gain for nanocrystal lasers and white light generation for nanocrystal based light emitting diodes. These processes are connected to different interfacial structures. Finally, we discuss two new applications based on surface electronic structure control: optical switching and optical thermometry. The work here suggests that the interface of nanocrystals should be a profitable route for chemical control of the electronic structure which can yield both performance enhancements as well as qualitatively different functional behavior