Noble metal-polymer and semiconductor hybrid nanocrystals and their applications

Abstract

Research on hybrid nanocrystals containing noble metals and other materials has intensified because an individual function of each component can be integrated into one system for specific applications. Synergistic optical and electrical properties are also expected due to interfacial coupling between distinct components. In the present research, we focused on the hybrid materials of metal with either polymers or semiconducting materials. Polymers on the surface of noble metal nanocrystals have a strong influence on surface characteristics which dominate physical and chemical properties of the nanocrystals. Furthermore, noble metal-polymer hybrid nanocrystals can introduce multiple functionality on the metal surface in a high density. In the case of noble metal-semiconductor hybrids, the metallic component can promote charge separation and enhance light absorption of the semiconductor domains, which makes this hybrid system optimal for photocatalytic reactions. In chapter 2, we employed three distinct surface regulating polymers, poly(vinyl caprolactam) (PVCL), poly(vinyl pyrrolidone) (PVP), and poly(N,N-dimethyl acrylamide) (PDMAm), for the synthesis of gold polyhedral nanocrystals under the modified polyol reaction conditions, and manifested that the adjustment of coordinating powers in the polymers can control particle sizes without changing polyhedral shapes. Particularly, the use of PDMAm generated carboxylate functionality on the gold surface by hydrolysis of the amide groups during the nanoparticle synthesis, which behaved as a linker to incorporate various biological molecules through ester and amide bond formation. Bovine serum albumin (BSA), a widely used protein, was also introduced as a surface regulating biopolymer to produce gold polyhedrons. Owing to its weak coordination power, BSA led to the underpotential deposition of Ag species the high-index facets other than Au(100) under a high concentration condition of $AgNO_3$, especially resulting in ...