Effects of bad solvents on thiatricarbocyanine particles formation

3,3′-Diethyl-thiatricarbocyanine iodide (DTTC) particles were prepared with solvent displacement approach. By varying the bad solvents, the products morphology was conveniently tuned from tabular shape (in n-pentane) to quasi-nanorods (in n-hexane) and spherical crystalline particles (in water). The intermolecular interactions between solvents and DTTC, and the cohesion parameters were used for evaluating the influences of bad solvents on the particles formation. It was proposed that the cohesion parameters could be used conveniently and quantitatively in choosing a bad solvent or a mixed bad solvent in the preparation of organic particles.