Optical properties of ion-pairs composed of diketo-pyrrolo-pyrrole disulfonyl dianion and ammonium or phoshonium cations.

abstract

English

Study of optical properties of molecules with high emission in the solid state has received considerable attention in recent years, particularly because of their multiple potential applications such as organic light-emitting diodes, organic solar cells, organic light emitting thin-film transistors and solid state lasers. An interesting class of materials for these applications represent organic ion pairs. Here we study solid-state fluorescence of four ion pairs with different sterically demanding cations. This relatively small variation of the chemical structure brings significantly different molecules geometry in crystals and thus diverse optical properties in solid state. Optical properties such as absorption, fluorescence, fluorescence quantum yield (PLQY) and lifetime in solution and in the solid state (crystal) were studied and discussed. It was found, that fluorescence emission spectra in solutions are nearly identical for all studied derivatives. The cation has no influence on the molecules geometry in solution. On the other hand, a large fluorescence emission red shift was observed in crystals. Also, the PLQY in solution varied between 50%–80% compared to the crystals where the PLQY variation was found to be much higher (2%–28%). The observed fluorescence lifetimes followed the trend of the PLQYs.

diketopyrrolopyrrole, ion pairs, fluorescence, fluorescence quantum yields, fluorescence lifetime

KOUTNÝ, J.; VALA, M.; WEITER, M.

5. 12. 2014

978-80-214-5077-6

Studentská odborná konference Chemie je život 2014, Sborník abstraktů

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