Electrochemical Coupling Layer-by-layer Assembly For Nanoparticles Composite Film And Its Hierarchical Composition Manipulation

Materials fabrication with nanoscale structural based on bottom-up-type self-assembly is of growing importance in various disciplines such as chemistry, physics and materials science. In particular, layer-by-layer(Lb L) assembly is known as a highly versatile method for fabrication of controlled layered structures from various kinds of component materials using very simple, inexpensive, and rapid procedures. Therefore, fabrication of multilayer films through the Lb L deposition process has attracted growing interest from various research communities. The high versatility and flexibility of Lb L assembly is continuously creating new concepts, new materials, new procedures, and new applications. However, conventional Lb L methods always need the complementary interaction(such as electrostatic, hydrogen bonding donor and acceptor, electron donor and acceptor interactions etc.) between the two assembly components as the driven force, which hampers the versitility of Lb L on effectively tunning the film hierarchical structure and makes it extremely difficult to fabricate single component film without auxiliary assembly counterpart. In this thesis, we introduced electrochemical coupling reaction of N-alkylcarbazole instead of complementary interaction between two molucules into the nanoparticles(NPs) Lb L filed, facilitating the hierarchical composition manipulating and assembly of single component NPs film. Specifically, the following works have been carried out:(1) Two kinds of organic small molecule ligand, namely COPA and CHT, were designed and synthesized. Using in-situ modification or subsequent ligand exchange process, we obtained the electrochemical-polymerizable nanomaterials of Pb S, Cd S and Au NPs bearing electro-active carbazole units.(2) The monodisperse multiple NPs are integrated successively into a thin bulk-hybrid gradient or multilayer films through tuning cycling number of cyclic voltammetry(CV), which is based on the quantitatively electrochemical deposition of each kind of NPs thanks to the electrochemical coupling reaction of N-alkylcarbazole ligand. This simple method yields transparent, stable and photoactive films with controllable hierarchical structure, exemplified by the prototype photodetector devices.