Reed Boduch

Abstract:

Charge transfer species, which create an electric field, play a central role in organic semiconductors. However, there is a lack of understanding of how these electric fields affect neighboring molecules. Using density functional theory, we investigate the effect of the external electric field on Tetracyanoquinodimethane (TCNQ), a paramount molecule in organic semiconductors. We saw a significant anisotropic effect in vibrational frequencies on the IR spectrum of TCNQ when the applied electric field was along with the symmetry axis of TCNQ. Further studies show a nonlinear field dependence on IR modes. Interestingly, a significant contribution to the vibrational spectral change is mainly due to the vibrational Stark effect. These findings can be used as an internal sensor to determine the localized electric fields of organic semiconductors quantitatively.