Theoretical determination and comparison of opto-electronic properties of some organic semiconductor molecules

This study was carried out within the scope of TÜBİTAK (1002) project numbered 117F286 in the Department of Physics, Faculty of Science, Karadeniz Technical University. Three novel organic semiconductors such as 9-[(5-nitropyridin-2-aminoethyl)iminiomethyl]-anthracene(a)andNꞌ-((pyren4yl)methylene)isonicotinohydrazide (b), and N-(2-((pyren-4-yl)methyleneamino)ethyl)-5-nitropyridin-2-amine (c) were worked. While compound (a) and compound (c) have the same wing unit ([(5-nitropyridin-2-aminoethyl) iminiomethyl]), compounds (b) and (c) have the same core unit (5-nitropyridin-2-amine). Based on DFT, TD-DFT and Marcus, Koopman's theories, we have explored the effects of molecular structure on the opto-electronic properties for OLED applications. Our results show that wing units of molecules impact more on the opto-electronics properties than on core units. The compounds (a) and (c) with the same wing unit have exhibited quite similar behaviors in terms of both structural and opto-electronic parameters. However, similar situation has not been observed for compounds (b) and (c) with the same core unit. In conclusion, our results indicate that compounds (a) and (c) exhibit obvious advantages for OLEDs in terms of calculated opto-electronic and charge transport properties such as better absorption and emission parameters, lower energy gaps and reorganization energies and higher charge mobility.