The detailed investigation on OLED features of some purely organic TADF materials

Computational chemistry has been a useful tool used in the design of new materials with desired properties utilized in organic optoelectronic structures such as organic light-emitting light diode (OLED) devices. In this article, comprehensive theoretical research using density functional theory (DFT) has been conducted on the OLED design of some pure organic molecules called DF materials. Firstly, the single point energies in different states of investigated DF molecules were determined at B3LYP/6–31 G(d) level in Gaussian program. From obtained the single point energies, the reorganization energy, the ionization potential, the electron affinity, and the chemical hardness values of the materials investigated were calculated. Additionally, the ground state molecular dipole moments, the frontier orbital shapes and the frontier orbital energy levels of the titled molecules were also achieved at same level. Secondly, the geometries and energies of the ground state (S0), the lowest singlet (S1) and triplet (T1) excited states of investigated DF compounds were defined at B3LYP/TZP level in Amsterdam Modeling Suite (AMS) program. The spin-orbit coupling matrix elements (SOCMEs), Marcus reorganization energies, the rates of reverse intersystem crossing (kRISC), the fluorescence and phosphorescence emission wavelengths of the studied DF materials were computed with the help excited states. Within the framework of theoretically acquired data, it was found that only DF3 and DF4 molecules could be used as electron transport layer material, whereas all investigated DF molecules can be utilized as hole transport layer material. Addition to this, it was emphasized that only DF3 and DF4 can be suggested as ambipolar materials. Additionally, an OLED structure in the form of ITO/DF2///DF3/Li, it was determined that DF2 and DF3 molecules could be used as hole injection layer and electron injection layer materials, respectively. Moreover, it was estimated that DF5 molecule could be preferred as a good electron blocking layer material. Finally, it was predicted that that DF4 could be used as a perfect candidate for NIR TADF OLED materials.