Theoretical investigation of the development of functional organic materials and application

In this work, a series of new organic emitting materials based on carbazole-triphenylamine and napthalimide derivation were investigated. The structural, energy level, absorption and emission properties were calculated by using density functional theory (DFT) and time-dependent density functional theory (TDDFT) method with B3LYP/6-31G(d,p) as implemented in Gaussian 09. The TDDFT calculated results revealed that the energy gaps were decreased when the strong electron withdrawing group were incorporated resulting in red-shifted of absorption and emission wavelengths. The calculated ionization potential (IP) reveals that target molecules can provided the efficient hole generating molecules. The results showed that the molecules can be used as multifunctional properties as the hole-transporting and emitting materials for application in OLEDs device.
Moreover, we have also studied the conformations, electronic and optical properties of porphyrin and coumarin dyes by using quantum chemistry with the same level of theory for the calculation of organic emitting material. The ground state structures, the intramolecular charge transfer (ICT) properties, the excitation energy were calculated. The effects of different donors, different linkers and different acceptors are included in this research. Our calculated results show that the ICT character involves primarily the promotion of an electron from the HOMOs to the LUMOs. The calculation results were compared with the experimental data. We also found that the calculation results are good agreement with experimental results. The modification of organic dye by using different linker can improve light harvesting