Solvatochromic study of triphenylamine derivatives: Estimation of the permanent dipole moment difference

Abstract

There is great interest in studying the optical properties of organic materials because of their fast optical response and excellent integrability in devices, which makes them attractive for applications in Photonics and organic electronics. Solvatochromism allows the analysis of the molecular microenvironment and provides information on the nature of the states responsible for the optical transitions of these materials. In this context, a solvatochromic study was performed on three molecules derived from triphenylamine bound to three electron acceptor groups; Cyanobenzene, Cyanopyridine and Dicyanobenzene, where their absorption and fluorescence spectra were analyzed; the difference of the maximum peaks was correlated with the Onsager polarity function from whose slope, the difference of the permanent dipole moment of each derivative was estimated. For all three molecules, a positive solvatochromism was observed, revealing that the permanent dipole moment of the first excited state is greater than that of the fundamental. As for the results of these differences, they are moderately high, suggesting that there is high electronic mobility throughout the organic compound, leading to the in ference that they will have a greater effect on nonlinear optical properties.