Presentation Title

Elucidating the Photochemistry of Molecular Aggregate-Templated Silver Nanowire Synthesis

Faculty Mentor

Justin Caram

Start Date

17-11-2018 10:30 AM

End Date

17-11-2018 10:45 AM

Location

C327

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

A bottom up approach to materials synthesis has the potential to serve as a cheap alternative for materials growth in nanoelectronic systems. We utilize self-assembling dye molecules as a template for growth of noble-metal nanowires. In solutions of methanol and water, amphiphilic cyanine dyes such as 3,3‘-bis(2-sulfopropyl)-5,5‘,6,6‘-tetrachloro-1,1‘-dicotyl-benzimidacarbo-cyanine (C8S3) form structures that assemble based on hydrophobic and hydrophilic properties. In this case, C8S3 forms a J-aggregate, whose absorption spectrum redshifts with respect to that of the monomer, to create a double-walled nanotube structure. This morphology can be used in a light-dependent redox reaction between the C8S3 aggregate and silver cation to form silver nanowires. We investigated several components of the light-dependent redox reaction responsible for nanowire synthesis to elucidate the reaction mechanism. To investigate the synthesis of self-assembled noble metal nanowires in solutions of dye aggregates, we explored photodegradation within the aggregates as light rapidly decreases characteristic absorbance peaks of the aggregate structure with and without the presence of a silver cation. Through kinetics studies, we found that this reaction strongly depends on the energy of the light source and the presence of oxygen.

Summary of research results to be presented

I will present an example spectrum showing how the reaction can be monitored with absorption spectra. I will also show rate data comparing the decrease in outer wall and inner wall peaks to show selectivity in oxidation of the outer wall. I will also show TEM images of nanowires produced using a 530 nm light source without oxygen presence.

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Nov 17th, 10:30 AM Nov 17th, 10:45 AM

Elucidating the Photochemistry of Molecular Aggregate-Templated Silver Nanowire Synthesis

C327

A bottom up approach to materials synthesis has the potential to serve as a cheap alternative for materials growth in nanoelectronic systems. We utilize self-assembling dye molecules as a template for growth of noble-metal nanowires. In solutions of methanol and water, amphiphilic cyanine dyes such as 3,3‘-bis(2-sulfopropyl)-5,5‘,6,6‘-tetrachloro-1,1‘-dicotyl-benzimidacarbo-cyanine (C8S3) form structures that assemble based on hydrophobic and hydrophilic properties. In this case, C8S3 forms a J-aggregate, whose absorption spectrum redshifts with respect to that of the monomer, to create a double-walled nanotube structure. This morphology can be used in a light-dependent redox reaction between the C8S3 aggregate and silver cation to form silver nanowires. We investigated several components of the light-dependent redox reaction responsible for nanowire synthesis to elucidate the reaction mechanism. To investigate the synthesis of self-assembled noble metal nanowires in solutions of dye aggregates, we explored photodegradation within the aggregates as light rapidly decreases characteristic absorbance peaks of the aggregate structure with and without the presence of a silver cation. Through kinetics studies, we found that this reaction strongly depends on the energy of the light source and the presence of oxygen.