Influences of Na+ and H+ on the spectroscopic properties and morphologies of a cyanine dye

In this paper, a cyanine dye was chosen to study the formation of J aggregates under the function of different ion sources (Na+ and H+). UV-vis spectra showed that adding either NaCl or HCl could promote dye to form J aggregates. So we investigated the different abilities of Na+ and H+ in forming J aggregates. The result indicated that the stimulative ability of H+ was stronger than that of Na+. Furthermore, we can also observe the morphology of the dye, which was coagulation of many gains before the addition of NaCl or HCl using Transmission Electron Microscopy (TEM). While it was changed to the short strands with a diameter of about 100 nm after adding NaCl to the dye aqueous solution, and comparably with the addition of HCl it became longer interlaced strands with an average diameter of about 200 nm.