Theoretical study of the photophysical and charge transport properties of novel fluorescent fluorine–boron compounds

Abstract

Two novel fluorine–boron compounds were recently synthesised that exhibit high fluorescent efficiency, and can potentially function as electron transport materials (ETM) and blue emitters. To reveal the relationship between the properties and structures of these functional materials, theoretical analysis of the spectral properties and charge transport properties were systematically investigated with B3LYP and the 6-31G* basis set. The absorption spectra are simulated using time-dependent DFT methods (TD-DFT), whereas the emission spectra are simulated by optimising the excited state by single-excitation configuration interaction (CIS) and then carrying out vertical CI calculations using the TD-DFT method. The results are in good agreement with experiment. The results show that the studied compounds can act as excellent electronic transportation materials based not only on the smaller electronic reorganisation energy, but also on the larger electronic transfer integral. The phenomenon of the blue shift of absorption spectra with increasing solvent polarity is explained. The solvent effects on absorption and emission spectra were examined using the PCM and COMSO models, respectively.

Keywords:

• quantum chemistry
• charge transfer
• excited state

Acknowledgements

The authors acknowledge financial support from the National Natural Science Foundation of China (project No. 20777029), the Educational Development Foundation of Jilin Province (No. 20070156), and the National Natural Science Foundation of Jiangsu Province (No. 07KJB610021).