Electronic and structural properties of organic field effect transistor materials

In this thesis, electronic and optical properties of semiconductor materials for organic field effect transistors were investigated. Electronic structure methods were used for optimization of selected structures and examination of their structural properties. Potential energy scanning was performed on the sensitive dihedral angles of bromomethyl substituted structure. Semiconductors with low frontier molecular orbital energy gap increase the mobility of holes and electron carriers in transistors and increase efficiency with low threshold voltage. The use of semiconductors with low frontier molecular orbital energy gap in battery systems reduces the operating voltage and makes the battery life efficient. In our study, frontier molecular orbital energy gaps of halogen substituted structures were calculated. In addition, these small organics used in liquid crystal synthesis and design as semiconductor layers are widely used in optoelectronic devices due to their easy polarizability and strong dipole properties. For this reason, nonlinear optical properties were calculated and the results were evaluated. In the static α, β, average γ and frequency dependent average α calculation results, structures with high values are suitable for the theory of frontier orbital energy gaps and nonlinear optical effects. It is concluded that bromomethyl substituted organic structure is more ideal and effective in the development of semiconductor layers compared to other halogen substituted structures in terms of electronic properties and nonlinear effects. The working materials and calculation methods provide significant contributions to the development of organic transistors and optoelectronic materials.