High-efficiency and high-quality white organic light-emitting diode employing fluorescent emitters

This paper reports a highly efficient organic light-emitting diode (OLED) with high-quality white emission that employs a deep blue-emitting beryllium complex bis(2-(2-hydroxyphenyl)-pyridine)beryllium (Bepp2) doped with a wide-bandwidth orange-emitting fluorescent dye 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4-H-pyran (DCM) through incomplete energy transfer from the blue host to the orange dopant. The two-component WOLED exhibits ideal and stable CIE coordinates (0.334 ± 0.002, 0.337 ± 0.007) with a high color rendering index equal to 79–81 upon variation in brightness from 10 to 10,000 cd m−2. As an all-fluorophore-doped white OLED, it yields very high EL efficiencies with the peak luminescence efficiency. The peak value of luminescence efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) is 14.0 ± 0.35 cd A−1, 9.2 ± 0.25 lm W−1, and 5.6 ± 0.15%, respectively.

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► WOLED uses two commercial fluorescent materials as the emitting materials.
► Two-component WOLED yields stable and ideal white CIE coordinates.
► All-fluorophore-doped WOLED presents very high EL performance (LE, PE and EQE).