Novel Counterflow Reactor for Continuous Templated Synthesis of Semiconductor Nanocrystals

Semiconductor nanocrystals are a class of materials exhibiting size-dependent and tunable optical and electronic properties. This allows for many different applicational usages such as display devices and biological. The commercial development of these nanocrystals requires the advancement of synthesis techniques that are scalable, as well as being both economical and environmentally friendly; simultaneously allowing for the control of the nanocrystals such as size, shape, and size distribution. The typical technique is the hot injection method which involves rapid injection of an organometallic precursor into a hot coordinating solvent where the nanocrystals grow as a function of time. Trying to commercialize this has many limitations including incomplete mixing, high cost, flammability and toxicity of the reactants, as well is an operator intensive process. Templated synthesis of nanocrystals has distinct advantages, including the ability to have precise control over the nanoparticle features such as the particle size, shape, and size distribution. The template consists of a stable microemulsion formed by the self-assembly of an amphiphilic block copolymer in the presence of both a polar and non-polar solvent. This microemulsion contains a group-II salt in the dispersed phase which is then contacted with a group-VI hydride gas reactant inside the nanodomains of the microemulsion. This technique is easily scalable to a continuous synthesis utilizing a packed bed reactor operated in counterflow where the gas phase reactant enters from the bottom of the reactor while the microemulsion is fed from the top of the reactor causing a concentration gradient allowing for the most efficient and cost-effective use of the reactants. The development of this reactor is explored as well as the optimization of the process by exploring different packing sizes, gas flow rates, as well as the startup conditions for the reactor. To increase the optical properties of the nanoparticles synthesized with this technique a post-processing technique involving both extraction from the microemulsion and functionalizing the nanocrystals surface was developed.

Name thesis:degree_name

Doctor of Philosophy

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Houston

Year dc:date.issued

2025

Author dc:creator

• Keister, Haley Krystine 1988-

Advisor dc:contributor.advisor

• Mountziaris, Triantafillos J.

Committee members dc:contributor.committeemember

• Chandra, Richa
• Dindoruk, Birol
• Karim, Alamgir
• Rimer, Jeffrey

• Chemical engineering

Language dc:language.iso

English

Handle dc:identifier.uri

https://hdl.handle.net/10657/19491

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/19491