ABSTRACT: D. functional theory (DFT) and time-dependent DFT (TDDFT) were employed to study ground-state properties, HOMOLUMO gaps (ÎH-L), excitation energies (Eg), ionization potentials (IPs), and electron affinities (EA) for PFV-alt-PDONV and PFV-alt-PDIH-PPV having different alternating groups. Excited-state properties were investigated using CI singles (CISs) while fluorescence energies were calcd. using TDDFT. The results show that PFV-alt-PDONV exhibits blue-shifted energies for both HOMO-LUMO gaps (ÎH-L) and excitation energies (Eg) compared with PFV-alt-PDIH-PPV. The predicted IP and EA clearly indicate that PFV-alt-PDIH-PPV has both easier hole creation and electron injection than that of PFV-alt-PDONV. The maximal absorption wavelengths of all polymers are strongly assigned to Ï â Ï* transition. The predicted radiative lifetimes of PFV-alt-PDONV and PFV-alt-PDIH-PPV for B3LYP/6-31G(d) are 0.36 and 0.61 ns, resp., indicating that PFV-alt-PDIH-PPV should have a better performance for long-time
International Journal of Photoenergy.