Optical spectroscopy of cyanine dyes J -aggregates in porous TiO2 matrices

The features of the formation of three cyanine dyes J -aggregates in a porous TiO2 matrix formed by positively charged microparticles were studied using optical spectroscopy. The formation of the J -aggregates was found to be better for cationic PIC and L-21 dyes compared to anionic BIC dye despite the charge of TiO2 particles. This manifests itself both in the color of the matrices and in the spectral properties of J-aggregates. For all the dyes, the degree of aggregation was much lower than in solutions, and the monomers made a significant contribution to the absorption spectra. For J-aggregates in TiO2 matrices, a weaker dipole -dipole interaction and a greater static disorder were found. Considering the spectral properties and stability, the PIC dye can be attributed to the best dye for the formation of J-aggregates in a porous TiO2 matrix formed by microparticles.