Unity fluorescent carbene–gold(I)–acetylide complexes with two-photon absorption and energy-efficient blue FOLEDs.

Two fluorescent organometallic "carbene–gold(I)–acetylide" (CMAc) complexes based on bicyclic alkyl(amino) carbene (BIC), 4-ethynyl-2,1,3-benzothiadiazole (Au1) and 4,7-diethynyl-2,1,3-benzothiadiazole (Au2) have been synthesized and characterized. Compounds Au1 and Au2 exhibit blue to yellow fluorescence with up to unity fluorescence quantum yields and radiative rates exceeding 10⁸ s⁻¹. The dipolar Au1 complex exhibits a low two photon absorption cross-section (2PA σ₂) of 0.8 GM, whereas the quadrupolar Au2 complex shows a high 2PA σ₂ value of 90 GM. A fluorescent CMAc organic light emitting diode (OLED) emits blue electroluminescence with up to 4.7% external quantum efficiency. [ABSTRACT FROM AUTHOR]