Fundamental studies of the surface chemistry and photoinduced charge transfer reactivity of tethered semiconductor nanoassemblies.

摘要

The focus of the research presented in this dissertation was two-fold: (1) the development of well-ordered assemblies of quantum dots (QDs) on surfaces through surfactant-mediated self-assembly; and (2) the study and characterization of photoinduced interfacial electron transfer from the QDs to the substrate. In particular, the dissertation focuses on the design and synthesis of well-ordered assemblies of CdE (E = S, Se) QDs bound to TiO 2 nanocrystalline films through molecular linkers, and the analogous systems in mixed suspension. Chapter 2 describes the synthesis of these materials and presents spectroscopic evidence for the proposed mechanism of assembly. Chapter 3 presents a systematic study of the influence of the length of alkyl molecular linkers on the efficiency of photoinduced interfacial electron injection from excited states of CdS QDs to acceptor states in TiO2 nanoparticles. To our knowledge, this was the first systematic spectroscopic study of the influence of interparticle separation on the efficiency of bridge-mediated electron transfer between semiconductor nanoparticles. In Chapter 4, the electronic coupling properties of molecular linkers incorporating aromatic phenyl rings were investigated.