First-principles studies of substituent effects on squaraine dyes
German Barcenas, Austin Biaggne, Olga A. Mass, Christopher K. Wilson, Olena M. Obukhova, Olga S. Kolosova, Anatoliy L. Tatarets, Ewald Terpetschnig, Ryan D. Pensack, Jeunghoon Lee, William B. Knowlton, Bernard Yurke, Lan Li
Abstract
conformation and substitution. We found that substituent effects are correlated with the empirical Hammett constant, which demonstrates their electron donating or electron withdrawing strength. Electron withdrawing groups were found to impact solvation free energy, transition dipole moment, static dipole difference, and absorbance more than electron donating groups. All substituents showed a redshift in absorption for the squaraine dye. In addition, solvation free energy increases with Hammett constant. This work represents a first step toward establishing design rules for dyes with desired properties for excitonic applications.