Synthesis and luminescent properties of perylene bisimide-cored dendrimers with carbazole surface groups

A group of perylene bisimide (PBI) cored dendrimers were designed and synthesized. The polyphenylene dendrons containing carbazole functional groups at periphery were attached to the PBI core with expectation to control the intermolecular interaction and to tune the charge transporting ability of dendrimers. Their photophysical, electrochemical and thermal properties were investigated. The spectral data showed that energy transfer and photoinduced charge transfer coexist between the carbazole peripheries and the PBI core, competing to influence the luminescent properties of these dendrimers. The red OLEDs were fabricated with these dendrimers as non-doped emitting layer by solution method. The dendrimers bearing carbazoles exhibited improved EL performance than those model compounds. The improved charge balance state caused by these carbazole units is suggested to be responsible for the EL performance.