Unity Fluorescent Carbene-Gold(I)-Acetylide Complexes with Two-Photon Absorption and Energy-Efficient Blue FOLED

Abstract

Two fluorescent organometallic “carbene-gold(I)-acetylide” (CMAc) complexes based on the 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.