In-situ evaluation of dye adsorption on TiO2 using QCM

We measured the adsorption characteristics of two organic dyes; triphenylamine-cyanoacrylic acid (TPA-C) and phenoxazine (MP13), on TiO2, directly in a solution based on quartz crystal microbalance (QCM). Monitoring the adsorbed amount as a function of dye concentration and during rinsing allows det...

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Bibliographic Details
Published in:EPJ Photovoltaics 2017, Vol.8, p.80401
Main Authors: Besharat, Z, Alvarez-Asencio, R, Tian, H, S Yu, Johnson, C M, Göthelid, M, Rutland, M W
Format: Article
Language:English
Subjects:
Adsorption
Atomic force microscopy
Chemical equilibrium
Dyes
Energy
Ethanol
Laboratories
Spectrum analysis
Sublimation
Sun
Titanium dioxide
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Summary:We measured the adsorption characteristics of two organic dyes; triphenylamine-cyanoacrylic acid (TPA-C) and phenoxazine (MP13), on TiO2, directly in a solution based on quartz crystal microbalance (QCM). Monitoring the adsorbed amount as a function of dye concentration and during rinsing allows determination of the equilibrium constant and distinction between chemisorbed and physisorbed dye. The measured equilibrium constants are 0.8 mM-1 for TPA-C and 2.4 mM-1 for MP13. X-ray photoelectron spectroscopy was used to compare dried chemisorbed layers of TPA-C prepared in solution with TPA-C layers prepared via vacuum sublimation; the two preparation methods render similar spectra except a small contribution of water residues (OH) on the solution prepared samples. Quantitative Nanomechanical Mapping Atomic Force Microscopy (QNM-AFM) shows that physisorbed TPA-C layers are easily removed by scanning the tip across the surface. Although not obvious in height images, adhesion images clearly demonstrate removal of the dye.
ISSN:2105-0716
2105-0716
DOI:10.1051/epjpv/2017002