Visualization of energy transfer among redox active polymeric colloids via in-situ fluorescence microscopy

Savsatli, Yavuz

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https://hdl.handle.net/2142/101219 Copy

Description

Title

Visualization of energy transfer among redox active polymeric colloids via in-situ fluorescence microscopy

Author(s)

Savsatli, Yavuz

Issue Date

2018-04-26

Director of Research (if dissertation) or Advisor (if thesis)

Braun, Paul

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

Redox Active Colloids, Electrochemistry, Energy transfer, Flow Battery

Abstract

The increasing contribution of intermittent renewable energy sources to the electrical grid is resulting in energy storage becoming more and more crucial to both improve grid stability and to enable increasing penetration of renewable in electrical generation. There are numerous number of technologies being considered for that purpose and redox flow batteries are considered one of the most promising designs for stationary energy storage due to their scalability, high-efficiency and decoupled control of energy and power. To prevent the crossover of energy carriers between anolyte and catholyte compartments of the flow battery, as one example, the redox active ethyl viologen agent has been covalently bound within crosslinked polymeric colloids. Little is currently known about how electrons (energy) transfers either within or between redox active colloids (RAC). To elucidate this, contact-mediated electron transfer between these redox active colloids (RAC) was characterized via confocal microscope using the intrinsic redox state-dependent electrofluorochromism of the RACs as the readout of the charge state of individual colloids. Via this approach, it was possible to map the redox-state of the system. By means of coupling a distinct fluorescent contrast with the respective redox state, intra- and inter- colloid energy transfer processes were reversibly imaged in situ, during electrochemical cycling. A three electrode in-situ cell setup was used for the cycling in which a Pt electrode used as the working electrode, carbon was used as the counter electrode and Ag/AgCl was used as the reference electrode. The system also showed a considerably increased sensitivity to fluorescence quenching. Investigation of the amplified sensitivity was done and this was attributed to fast electron hopping among neighboring redox groups.

Graduation Semester

2018-05

Type of Resource

text

Permalink

http://hdl.handle.net/2142/101219

Copyright and License Information

Copyright 2018 Yavuz Savsatli

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