CH2, NH, and O heteroatom substitution effects on the electronic, optical, and charge transport properties of a 2,1,3-benzothiadiazole-based derivative： Insights from theory

A set of CH2-, NH-, and O-substituted 2,1,3-benzothiadiazole （BTD）-based derivatives have been investigated theoretically in order to explore their electronic, optical, and charge transport properties. The calculation results show that the electronic and optical properties of the pristine molecule can be easily tuned through changing the S substituent in the central aromatic ring. Based on the calculated maximum emission wavelength, we predict that CH2-, NH-, and O-substituted BTD-based derivatives could be used as red, green, and orange light-emitting materials, respectively. After CH2-, NH- or O-substitution, the oscillator strengths of the emission spectra are enhanced with respect to that of the pristine molecule, implying that these compounds have larger fluorescence intensity. Finally, it can be deduced that CH2-, NH-, and O-substituted BTD-based derivatives may act as hole transport materials in organic light-emitting diodes.