Exploring the 3-(phenylethynyl)-9H-carbazole unit in the search of deep-blue emitting fluorophores

Abstract

Two new types of molecular constructions based on the 3-(phenylethynyl)-9H-carbazole moiety have been developed. Specifically, the synthesized bicarbazole and triethynylbenzene derived fluorophores display emission ranging from deep-blue to green-blue in the solid state, depending on the N-alkyl chain length and their intermolecular arrangement, which has been elucidated from the crystallographic data. Their photophysical and electrochemical properties have permitted the construction of blue OLEDs with a simple device architecture compatible with the solution-processing. In addition, the combination of the synthesized emitters with a small ratio of commercial iridium complexes has allowed the preparation of pure white OLEDs by spin coating the different layers. The characteristics of the emitted white light depend not only on the emissive layer composition but also on the applied voltage, standing as two key factors to easily modulate the color temperature.