Group-V Chemistry of Semiconductor Nanocrystals

Pnictide semiconductor nanoparticles and quantum dots are important class of materials due to their potential applications in solar cell, thermoelectricity, bioimaging and biosensors. However, scientific communities’ attention on pnictide materials was negligible compared to conventional II-VI chalcogenide based QDs. This is primarily due to the challenging syntheses of group V semiconductor nanoparticles compared to II-VI families. This thesis focuses on the development of safe and effective methods for the synthesis of a wide variety of pnictide semiconductor nanoparticles, or quantum dots including materials within the III-V, II-V, I-V-VI2 and I3-V-VI4 families. In first chapter, I have reported a relatively air-safe and less hazardous arsenic precursor, bis-[N,N-bis-(trimethylsilyl)amido] chloroarsenic, [(Me3Si)2N]2AsCl (arsenic silylamide) that can be used to create a variety of crystalline, monodisperse II-V, III-V, and I3-V-VI4 family semiconductor quantum dots. The mechanism of the formation of quantum dots was also elaborated with the help of DFT calculation and NMR experiments. Next, I have expanded the scope of these silylamide-associated pnictide precursors, tris[N,N-bis(trimethylsilyl)amido]antimony, [(Me3Si)2N]3Sb and tris[N,N-bis(trimethylsilyl)amido]bismuth, [(Me3Si)2N]3Bi towards the exploration of novel antimony and bismuth nanomaterials, AgSbSe2 and AgBiSe2. Furthermore, electrical measurements of these materials were performed to characterize the electrical properties of the nanoparticles. In addition to pnictide nanomaterials’ syntheses, I have developed a series of hydrophilic phosphonic acids to solubilize QDs in aqueous solution using a variety of strategies. This project focuses to minimize the number of steps for water solubilization and enhance the efficacy of functionalization of QDs.