Computation Aided Design in Molecular Nanotechnology

Citation

Deng, Wei-Qiao (2004) Computation Aided Design in Molecular Nanotechnology. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3EKY-3J53. https://resolver.caltech.edu/CaltechETD:etd-05282004-161503

Abstract

We use multi-scale simulation strategy to understand, improve and rationally design novel materials with desired properties in molecular nanotechnology. The areas we have studied cover from molecular electronics, nano-structured materials to carbon nanotube technology.

In term of molecular and nano-electronics, first we used quantum mechanics to characterize the structure and current-voltage (I-V) performance of the Stoddart-Heath rotaxane-based programmable electronic switch. This methodology established a basis for iterative experimental-theoretical efforts to optimize systems for molecule-based electronics. We extended this switch principle and rationally designed an ultrafast molecular switch, proton-hopping molecular switch. Second we developed a kinetic model to study the hole mobility in organic semiconductor. After screening several designs, we presented a nano-bracelet as a competitive organic semiconductor.

We studied several topics related to the applications of nano-structured materials in fuel cell technology. Based on our simulation, we proposed a new kind of carbon-based materials for hydrogen storage. It can satisfy the target set up by the Department of Energy, USA. We develop a kinetic model to study the proton diffusion in proton exchange membrane of hydrogen fuel cell. We validated our proposed system, fluorinated imidazole impregnated nafion, as the candidate that can transfer proton above 100 0C at water-free media.

In term of carbon nanotube technology, we explored the reason why bimetallic catalysts are 10-100 times better than mono-metals at assisting single wall carbon nanotube growth. Based on our proposed two-stage growth mechanism, we screened and designed a better catalysis.

Thesis Files