Synthesis And Properties Research Of High Quality RNCs And MSCs Nanocrystals

Nano-scaled semiconductors (viz quantum dots, QDs) have received increasing interests in many fields, such as health (fluorescent biological labels), energy (photovoltaic cells) and light-emitting device. In this thesis, the synthesis and properties of high quality RNCs (regular nanocrystals) and MSCs (magic-sized nanoclusters) have been studied, including CdS/CdSe core/shell nanostructures, Cu:ZnxCd1-xSe doped alloys, CdTe and ZnTe MSCs.In Chapter1, the recent progress and the principle theories of semiconductors (RNCs and MSCs) have been reviewed.In Chapter2, high quality inverted type-â…  CdS/CdSe core/shell nanostructures with different absorption onsets have been synthesized via the well-developed hot injection method. These QDs were deposited onto mesoporous TiO2electrodes after transferred into water phase by linking with mercaptopropionic acid (MPA), and the resulting quantum dot sensitized solar cells (QDSCs) exhibited record conversion efficiency of5.32%under simulated AM1.5,100mW cm-2illumination.In Chapter3, Cu:ZnxCd1-xSe doped alloys with tunable PL emission covering the entire visible spectrum (from440to710nm) have been prepared via a facile noninjection and low cost green approach using ODE-Se as precursors. We conclusively demonstrate that Cu impurities represent paramagnetic+2species and serve as a source of permanent optically active holes.In Chapter4, various kinds of CdTe MSCs and ZnTe MSCs have been controlled synthesized. Green Zn(OAc)2was used as precursor instead of diethyzinc to synthesize ZnTe MSCs. In order to control the morphology and the properties of the CdTe MSCs, different ligands were used to synthesize CdTe MSCs.