Turning InP nanocrystals up to 11: Coinage Metal Cation Exchange in InP Nanocrystals

Abstract

Cation exchange is a powerful method to expand the versatility and properties of a semiconductor nanocrystal. By tuning the amount of exogenous cation a spectrum of new materials can be accessed, including doped nanoparticles, alloyed nanocrystals, and even fully exchanged nanomaterials that may be challenging or impossible to create via traditional synthetic methods. This thesis focuses on the cation exchange of coinage metal (Cu, Ag, Au) cations in InP nanomaterials. Chapter 1 will provide an introduction to core concepts and background related to quantum dots, clusters, and dopant-dependent properties. In chapter 2, we will discuss the development of a new methodology to dope InP quantum dots with Cu+ ions, and the effect that surface treatments have upon the photophysics of these Cu+:InP nanocrystals. In chapter 3, electron transfer to molecular acceptors from undoped and coinage metal (Cu, Ag) doped InP quantum dots is investigated, finding that the long lived photoexcited states imparted by doping QDs greatly enhance the likelihood of electron transfer. In chapter 4, coinage metals (Cu, Ag, Au) are exchanged into atomically precise In37P20(O2CC13H27)51 magic sized clusters (MSCs). The exchange of cations in the InP lattice can be tuned either creating doped InP-MSCs, or driven to completion, creating coinage metal-phosphide clusters. These materials have distinct spectroscopic and structural characteristics, and can serve as precursors for forming larger nanoparticles, including previously unreported materials.