Open AccessPotential dependent spectroelectrochemistry of electrofluorogenic dyes on indium‐tin oxide
Author(s) -
Sundaresan Vignesh,
Cutri Allison R.,
Metro Jarek,
Madukoma Chinedu S.,
Shrout Joshua D.,
Hoffman Anthony J.,
Willets Katherine A.,
Bohn Paul W.
Publication year - 2022
Publication title -
electrochemical science advances
Language(s) - English
Resource type - Journals
ISSN - 2698-5977
DOI - 10.1002/elsa.202100094
Subject(s) - indium tin oxide , indium , chemistry , tin , oxide , inorganic chemistry , materials science , photochemistry , nanotechnology , optoelectronics , organic chemistry , electrode
Indium‐tin oxide (ITO) is used in a variety of applications due to its electrical conductivity and optical transparency. Moreover, ITO‐coated glass is a common working electrode for spectroelectrochemistry. Thus, the ITO substrates should exhibit well‐understood spectroscopic characteristics. Here, we report anomalous potential‐dependent luminescence emission from three structurally dissimilar electrofluorogenic probe on ITO‐coated glass. The three probes, flavin mononucleotide, resorufin, and Nile blue, show the expected fluorescence modulation between their oxidized, emissive forms and their reduced, nonfluorescent forms at low laser irradiance and/or high concentrations. However, at high irradiance and/or low concentration, the emission intensity increases at reducing potentials, contrary to expectations. In addition, a strong interplay between probe molecule concentration and laser irradiance is observed. We attribute the anomalous behavior to a combination of (1) irradiance‐dependent ITO carrier dynamics, and (2) interaction of the fluorescent probe with ITO at reducing potentials resulting in a charge transfer state with altered emission behavior. Thus, the potential‐ and irradiance‐dependent behavior of ITO and the resulting charge transfer state may not only interfere with the observation of potential‐dependent fluorescence from redox probes but can completely reverse the polarity of the potential‐dependent luminescence, especially at high irradiance and low concentration.