A Biphasic Ligand Exchange Reaction on CdSe Nanoparticles: Introducing Undergraduates to Functionalizing Nanoparticles for Solar Cells

Abstract

Semiconductor nanoparticles, including cadmium selenide (CdSe) particles, are attractive as light harvesting materials for solar cells. In the undergraduate laboratory, the size-tunable optical and electronic properties can be easily investigated; however, these nanoparticles (NPs) offer another platform for application-based tunability—the NP surface. In the interest of exploiting these particles for solar applications, the surface can be tuned to facilitate charge transfer out of the nanoparticles to maximize photocurrent for high-efficiency, low-cost solar cells. This multiweek undergraduate laboratory experiment introduces students to semiconducting nanomaterials and to taking steps to ensure functionality of these materials for solar applications. The experiment includes the synthesis of oleic acid-capped (OLA) CdSe particles and a biphasic ligand exchange reaction to afford ionically functionalized CdSe nanoparticles capped with sodium 3-mercaptopropane-1-sulfonate (MPS). Both the CdSe-OLA and CdSe-...