| 초록 |
Since triplet excitons can’t be directly utilized via fluorescence process, fluorescent organic light-emitting diode(OLED) has low efficiency using only 25% excitons. However, it has a good advantage such as high color purity, cost-efficiency and stability, so it is necessary to develop. Donor-acceptor molecular structure with large dipole moment can induce effective charge transfer(CT) character along with HOMO(highest occupied molecular orbitals) and LUMO(lowest unoccupied molecular orbitals) separation. It results in large stokes shift and broad emission spectrum. Ultimately, it has a damaging effect on color purity for high-resolution OLED display applications. So, it is important that there is no CT character for high color purity. In this study, new nitrogeneous heterocyclic structures were synthesized and CT characters were investigated by DFT calculation. According to the CT character of the structures, it showed the effect on stokes shift and FWHM(full width at half maximum). |
