The dielectric function of silver nanoparticle Langmuir monolayers compressed through the metal insulator transition

S. Henrichs, C. P. Collier, R. J. Saykally, Y. R. Shen, J. R. Heath

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Algorithms and experimental techniques for extracting the complex dielectric function of thin films (monolayers and bilayers) of quantum dots are developed. The algorithms are based on a combination of the so-called Newton-Raphson method, used in conjunction with a Kramers-Kronig analysis, and are used to analyze normal-incidence reflectance and transmission measurements of organically passivated silver quantum dot Langmuir monolayers. Single, unambiguous solutions to the dielectric function were determined for several particle monolayers and at various stages of compression. A transition of the quantum dot superlattice from the insulating to a metallic state was observed. When a monolayer of 6-nm-diameter Ag nanocrystals is compressed to an interparticle separation distance of ~8-9 Å, a negative-valued featureless component of the real part of the dielectric function is detected. This indicates the onset of Drude-like behavior that is characteristic of a metallic film. The impact of superlattice disorder on this Drude response is also investigated.

Original languageEnglish
Pages (from-to)4077-4083
Number of pages7
JournalJournal of the American Chemical Society
Volume122
Issue number17
DOIs
StatePublished - May 3 2000
Externally publishedYes

Fingerprint

Dive into the research topics of 'The dielectric function of silver nanoparticle Langmuir monolayers compressed through the metal insulator transition'. Together they form a unique fingerprint.

Cite this