文摘
The electronic structures and photophysical properties of a series of cyclometalated iridium (III) complexes Ir(C∧N)2(H2NNHCOO), including 1 [C∧N=2-phenyl-pyridine], 2 [C∧N=5-fluoro-2-phenylpyridine], 3 [C∧N=2-phenyl-5-trifluoromethylpyridine], 4 [C∧N=6-phenyl-[2, 3] bipyridinyl], 5 [C∧N=7-phenyl-cyclopenta [4] dipyridine] and 6 [C∧N=8-phenyl-[1, 9] phenanthroline], have been theoretically investigated based on density functional theory (DFT) and time-dependent DFT. The characteristics in phosphorescent performances have been outlined for each of the complexes in the applications in OLED. On the basis of the two simplifications presented in this paper and the available experimental data, the magnitudes of phosphorescent radiative rates for complexes 1–6 were approximately calculated to be: 5.56×105 s−1, 2.68×105 s−1, 1.17×106 s−1, 9.78×104 s−1, 5.30×106 s−1 and 6.71×106 s−1, respectively. Meanwhile, the sequence of phosphorescent quantum efficiencies was obtained to be: ФPL(4)<ФPL(2)<ФPL(1)<ФPL(3)<ФPL(5)<ФPL(6), in which ФPL(4) is by far the lowest, ФPL(5) is much larger and ФPL(6) is by far the largest. In contrast to complex 1, the emission wavelengths are slightly red-shifted for 2 and 3 and significantly red-shifted for 4 and 5, while the emission wavelength of 6 is slightly blue-shifted. In comparison, complexes 6 and 5 may be singled out to be the most efficient phosphorescence emitters for the applications in OLED.
