PYD2 were fabricated. As a result, the maximum EQE was
improved to 2.0% for 1, 6.1% for 2 and 7.4% for 3.
In conclusion, we developed a luminescent Cu complex with
improved PL quantum efficiency based on the effective strategy
of suppressing not only the excited-state distortion but also C–H
vibrational quenching. An OLED containing the Cu complex
demonstrated efficient luminescence with EQE = 7.4%.
This research was supported by the Japan Society for the
Promotion of Science (JSPS) through its ‘‘Funding Program for
World-Leading Innovative R&D on Science and Technology
(First Program)’’.
Notes and references
Fig. 4 Dependence of EQE on current density for OLEDs with the
structure ITO/PEDOT:PSS (40 nm)/X wt% of Cu complex:PYD2
(30 nm)/DPEPO (50 nm)/LiF (0.7 nm)/Al (100 nm). Inset: EL spectra
of OLEDs containing 1, 2 and 3.
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ITO/PEDOT:PSS (40 nm)/10 wt% of 1, 2 or 3:PYD2 (30 nm)/
DPEPO (50 nm)/LiF (0.7 nm)/Al (100 nm) (ITO is indium tin
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(Fig. 4, inset). The maximum EQE was 1.6% for 1, 3.0% for 2
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the PL quantum efficiency described above (Fig. 4). To further
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c
5342 Chem. Commun., 2012, 48, 5340–5342
This journal is The Royal Society of Chemistry 2012