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Title: Study of morphology of colloidal nano-materials
Author: Chen, H.-S.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2009
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This study is an investigation of the morphology of nano-materials synthesized from colloidal solutions, by the generalized sol-gel process but specifically via 3 modes solution-sol, sol-gel, and solution-gel methods. In the solution-via sol study, magic closed-shell CdSe nanocrystals (NCs) are synthesized and shown that the crystal growth has a discontinuous event, explaining by the hypothesized “chemical potential well”. Based on the chemical potential well model, nanocrystals with a controllable multi-modal size distribution, for example, nanocrystals with 2.2 nm ± 9% and 3.6 nm ± 9% in a simple one-pot synthesis are synthesized. The morphology of sol-gel TiO2 nanoparticles (NPs) synthesized by a vapour hydrolysis of titanium isopropoxide where the hydrolysis is caused by the condensation of vapour having relatively slow hydrolysis is studied. Experimental results suggest that TiO2 nanoparticles are made up of secondary particles composed of uniform primary nanoparticles, which are amorphous before an annealing process is performed. For the solution-gel, synthetic chemistry of LZO nanocrystalline film is examined. four major experimental parameters are identified and optimized by employing the Taguchi statistical method: the ratio of lanthanum acetate to propionic acid, the concentration of precursor solution used in the inkjet printing system, the annealing temperature, and the heating rate. The film synthesized using the optimum conditions reveals a dense surface morphology and high out-of-plane lattice alignment. All 3 approaches for the 3 different materials can generate uniform primary particles that can be either controlled at those discrete sizes (CdSe), or be agglomerated into secondary particles (TiO2), or be densified into a textured film (La2Zr2O7).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available