Synthesis and optoelectronic properties of a solution-processable anthraquinone/fluorene hybrid bipolar fluorescent material

The solution-processable, anthraquinone-based, fluorene bipolar fluorescent material 2-(9, 9’-bis (2-ethylhexyl)-9H-fluoren-2-yl)anthracene-9, 10-dione (FAA) was synthesized via a Suzuki reaction. The photophysical properties of FAAwere subsequently investigated by acquiring absorption and photoluminescence spectra, and its optical properties were studied using computational density functional theory methods. Data obtained from single-carrier devices incorporating FAA demonstrated its well-matched bipolar charge-transport characteristics. The electroluminescence performance of this material was also examined by doping FAA into a 1, 3-di(9H-carbazol-9-yl)benzene (mCP) matrix as the light-emitting layer via spin coating to produce an organic light-emitting diode (OLED) with an indiumtin oxide (ITO)/poly(3, 4-ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS)/mCP:FAA/3, 3’-(5’-(3-(pyridin-3-yl)phenyl)-[1, 1’:3’, 1”-terphen-yl]-3, 3”-diyl)dipyridine (TmPyPb)/LiF/Al structure. This device exhibited a maximum luminance of 1719 cd·m⁻² with a turn-on voltage of 7.4 V, along with maximum current and power efficiencies of 1.66 cd·A⁻¹ and 0.56 lm·W⁻¹, respectively. The electroluminescence mechanism of the OLED is discussed based on the energy level diagrams of the functional layers.