Exploring and enhancing conductivity in semiconductor nanoparticle films

Semiconductor nanocrystals (NCs) are a promising material for use in opto-electronic devices as their optical properties tune with particle size. NCs formed via colloidal synthesis are suspended in solution by the organic ligands which passivate the NC surface after synthesis, and NCs can be deposited from solution to form NC solids. In theory, 'designer solids' having different electrical properties can be formed by changing, and even mixing, the types of NCs in the NC solids. However, the organic ligands capping each NC hinder charge transport between NCs in the solid. This thesis presents a study of how methods developed to enhance conductivity alter the physics of charge transport through the NC solid. Chapter 2 describes a post-deposition ligand exchange that decreases interparticle spacing and increases photogenerated current by over three orders of magnitude. In addition, the larger currents allow for the investigation of the nature of the CdSe NC/gold electrode interface which is found to impede electron and hole injection into the NC film. In Chapter 3 the electronic height of the tunnel barrier between CdSe NCs is changed by separating NCs with a thin ZnS inorganic shell rather than organic ligands.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Porter, Venda Jane

Advisor dc:contributor.advisor

• Moungi G. Bawendi.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/39675

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/39675