Lanthanoid β-triketonates: a new class of highly efficient NIR emitters for bright NIR-OLEDs.

The reaction of hydrated YbCl3 with potassium tribenzoylmethanide yields a new bimetallic tetranuclear Yb(3+)/K(+) assembly. This species not only possesses the longest excited state lifetime and quantum yield reported for the Yb(3+) diketonate family but is also suitable to be incorporated in NIR-OLEDs, whose performance outclasses any other reported lanthanoid-based device with NIR emission.