Controlling electronic effects and intermolecular packing in contorted polyaromatic hydrocarbons (c-PAHs): towards high mobility field effect transistors

摘要: We have investigated the electronic and charge transport properties of two regioisomeric contorted polyaromatic hydrocarbons at molecular level as well in crystalline state. Electron hole is studied on basis an incoherent hopping model through DFT calculations. For trifluro-dibenzoperylene (CF3-DBP, 1), which crystallizes a herringbone network, computed drift electron mobilities are 0.234 0.008 cm2 V−1 S−1, respectively. The greater mobility DBP crystal (μh/μe = 29) can be rationalized by its lower reorganization energy higher transfer integral simultaneously. These calculations for pristine differ from recent experiments indicating preferential conductivity. This might attributed to interaction molecules with gold source/drain electrodes. Its second regioisomer, 2, having HOMO–LUMO gap 3.2 eV thus expectedly inefficient, converted into effective OFET material replacing Ph-CF3 groups oxo (>CO) 9 10 positions (9,10-dioxotribenzopyrene, 3). 3 has suitable 2.18 eV. bowl-shaped molecule predicted pack stacked orientation concave⋯concave pairs short intermolecular distance 4.15 A identical inter-chromophoric electron/hole coupling (th ∼ te). creates ambipolar behavior 3. Clearly, fine tuning structure–property relationship opens up possibility implanting tailored existing library molecules.