Computational Insights into the Effect of Noncovalent S···S Interaction on the Excited-State Characteristics of...

The photophysical properties of the designed molecules were investigated by theoretical calculations. The introduction of thiophene units into the DABNA-1 core reduces both S₁ and T₁ energies, whereas the derived ∆E_ST values become larger. As revealed by normal mode analysis for all designed molecules, the designed molecule, including the S···S interaction, exhibits the lowest reorganization energy during the excitation and de-excitation. Vibrationally resolved emission spectra further show that S···S interaction plays a pivotal role in reducing the spectrum width. Comprehensively, it is evident that the S···S interaction is a useful chemical design strategy to suppress the k_nr and enhance the color purity for OLED emitter.