Recently, about nanoparticle research, control and applications of materials’ properties have been studied actively with developing synthesis skill and systematic advances such as controllable nanoparticles’ shapes, growth mechanism, monodispersity, and stoichiometry. However, the most established one was limited singular nanoparticle property research only and simple nanoparticles spread on the substrates. Here, we will introduce the new concept of materials or elements which show different properties from individuals using superlattices; periodically stacked or assembled by monodiserse nanoparticles. Each electrical, magnetic and optical properties was measured using PbS, CoFe2O4, and CdSe nanoparticles made by hot-injection method. In this paper, we will show results of the artificial 3D nano-structures self-assemble structure, which can be controlled by solvent evaporation ratio, surface control of nanoparticles, and so on. Also, we have studied the effect of nanoparticles’ stoichiometry, size, and shape for superlattice growth, and compared electrical, magnetic, and optical properties of superlattices with one of individual. ⓒ 2014 DGIST
Table Of Contents
1. Introduction 1 -- 2. Experiments 5 -- 2.1. Synthesis method of CoFe2O4 nanoparticles 5 -- 2.2. Synthesis method of Fe3O4 nanoparticles 5 -- 2.3. Synthesis method of ZnFe2O4 nanoparticles 5 -- 2.4. Synthesis method of Co nanoparticles 6 -- 2.5. Synthesis method of PbS nanoparticles 6 -- 2.6. Synthesis method of Fe3O4 colloidal nanocrystal clusters 6 -- 2.7. Synthesis method of CdSe@CdS (core@shell) nanoparticles 7 -- 2.8. Superlattice growth method 7 -- 2.9. Supercrystal growth method 8 -- 2.10. Characterization techniques used in this work 8 -- 3. Results & Discussion 10 -- 3.1. Magnetic nanoparticle synthesis & characterization 10 -- 3.2. Semiconductor nanoparticle synthesis & characterization 15 -- 3.3. Superlattice & Supercrystal characterization 17 -- 3.4. Electrical properties of supercrystal 24 -- 3.5. Magnetic properties of supercrystal 28 -- 3.6. Optical properties of supercrystal 32 -- 4. Summary & conclusion 34 -- References 35
