Synthesis, Properties, and Application as Emitters in Organic Electroluminescence Devices of Quinacridone- and Squarylium-Dye-Centred Dendrimers

The UV–vis absorption and fluorescence spectra, solubility, and application as emitters in single-layer organic electroluminescence (EL) devices of novel quinacridone- and squarylium-dye-centred dendrimers (Gn-QAs and Gn-SQs) were examined. The respective dendrimers showed no remarkable differences in the UV–vis absorption (λmax) and photoluminescence (PL) maxima (λem). The solubility of dendrimers drastically increased at higher generation. The EL maxima of Gn-QAs and Gn-SQs were observed at 522 and 710 nm, respectively. In the case of Gn-QAs, the EL intensity under the fixed bias voltage decreased at higher generation due to a decrease in energy transfer from the host molecules to QA. Meanwhile, in the case of Gn-SQs, the EL intensity increased upon higher generation because of increased current density and the improvement of concentration quenching.