Design principles to tune the optical properties of 1,3,4-oxadiazole-containing molecules

ORGN 82

Onas Bolton, obolton@umich.edu and Jinsang Kim, jinsang@umich.edu. Department of Materials Science and Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109
In order to provide a clearer picture of the specific photophysical properties of the 1,3,4-oxadiazole moiety we have synthesized a series of oxadiazole compounds and ethynylene analogs. Our results show that the ring is both optically transparent in the visible range and fully conjugating. We have also discovered the presence of a non-radiative mechanism active in molecules containing typical para-dialkoxy substituents adjacent to the oxadiazole ring, which can reduce quantum yield by as much as 50%. Results suggest that this is resultant of an intramolecular repulsive interaction that we believe prevents excited-state planarity. This mechanism is preventable through design principles presented here. In whole our results provide a complete and clear picture of the effects of 1,3,4-oxadiazole on the photophysical properties of conjugated organic molecules and valuable design principles for optical property optimization of its organic optoelectronic materials.