Comparative DFT studies of UV-vis and fluorescence spectra of diphenylamino-nitro-trans-stilbene

DFT calculations have served as a critical tool to understand and design organic small molecules for many applications in the field of photoelectronics. Although many efforts have been made towards accurately describing UV-vis and fluorescence properties of organic small molecules, there are much needs to evaluate the accuracy of various functionals in description of electronic properties of organic small molecules. In this work, we make comparisons of ten functionals, i.e. B3LYP, HSEH1PBE, CAM-B3LYP, PBE, HCTH, LSDA, BVP86, B3PW91, MPW1PW91, wB97XD, in the calculation of the energies of the frontier orbitals, UV-vis and fluorescence spectra of diphenylamino-nitro-trans-stilbene and with the experimental results. DFT calculations were carried out for both the ground and excited states and TD-DFT calculations were performed to obtain the UV-vis and fluorescence spectra. For the orbital energies, B3LYP and B3PW91 provide the best result with respect to the experiment. For UV-vis and fluorescence, CAM-B3LYP and MPW1PW91 results are closer to the experiments. Structural comparisons between the ground and excited states of the molecule were also made.