Electronic Excited States of Carotenoid Dyes Adsorbed on TiO2 - The

ARTICLE pubs.acs.org/JPCC

Electronic Excited States of Carotenoid Dyes Adsorbed on TiO2 Staniszaw Krawczyk*,† and Agata Zdyb‡ † ‡

Institute of Physics, Maria Curie-Skzodowska University, 20-031 Lublin, Poland Faculty of Environmental Engineering, Lublin University of Technology, 20-618 Lublin, Poland

bS Supporting Information ABSTRACT: The fast development of new organic sensitizers for the purposes of dye-sensitized solar cells and photocatalysis requires a better understanding of the complexity of their electronic states on TiO2 surface. This paper describes a study of carboxylated derivatives of all-trans carotenoids retinoic acid (ATRA) and bixin by Stark effect (electroabsorption) spectroscopy in glassy ethanol at low temperature, both as free monomeric species and when adsorbed to nanoparticles of titanium dioxide in the presence of a variable concentration of acetic acid. Both pigments adsorbed strongly at the lowest acid contents (