Solution-processable stiff dendrimers: synthesis, photophysics, film morphology, and electroluminescence.

A series of solution-processable conjugated dendrimers (T1-T5) consisting of a pyrene core, fluorene/carbazole dendrons, and acetylene linkages have been successfully synthesized and fully characterized. The effects of generation on the photoluminescence (PL) and electroluminescence (EL) of dendrimers are investigated. Photon harvest and energy transfer are observed in these dendritic systems. Efficient electroluminescent single layer dendrimer devices are achieved through control of dendrimer generation and optimization of spin-coating speed. A T3-based device exhibits yellow EL (CIE: 0.49, 0.50) with a maximum brightness of 5590 cd/m(2) at 16 V, a high current efficiency of 2.67 cd/A at 8.6 V, and a best external quantum efficiency of 0.86%.