Journal Article

FZJ-2021-04862

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Formation of controllable pH gradients inside microchannels by using light-addressable electrodes

Welden, R. ; Gottschalk, C. ; Madarevic, I. ; Van Bael, M. J. ; Iken, H.RWTH* ; Schubert, J.FZJ* ; Schöning, M. J.FZJ* ; Wagner, P. H. ; Wagner, T. (Corresponding author)FZJ*

2021
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/30083  doi:10.1016/j.snb.2021.130422

Abstract: Understanding the influence of the pH value towards microenvironments of bioanalytical systems, especiallyinside lab-on-a-chip or micro total analysis systems, is crucial for the success of experiments. Different ap­proaches are known to control the pH value inside those microchannels and to tailor pH gradients. Nevertheless,the existing concepts often lack the possibility for a flexible adaption of these gradients. To overcome thislimitation, the present work reports on light-addressable electrodes (LAEs) as a tool to create pH gradients at themicro scale. Light-addressable electrodes are based on semiconductor materials in which electron-hole pairs aregenerated by illumination. These free charge carriers can trigger chemical reactions at the semiconductor-electrolyte interface, including the change of the pH value. For this purpose, we have designed LAEs based onglass/fluorine-doped tin oxide/titanium dioxide heterostructures. This work studies the influence of the appliedexternal potential, illumination brightness and illumination area on the maximum pH change and width of thepH gradient using a pH-sensitive fluorescent dye. Furthermore, we evaluate the correlation between the pHchange and electrical charge transfer. Finally, we provide an outlook towards tailoring complex pH gradientsinside microchannels.

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Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)

Research Program(s):

1. 5233 - Memristive Materials and Devices (POF4-523) (POF4-523)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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