Ionic iridium(III) complexes are emerging with great promise for organic electronic devices, owing to their unique features such as ease of molecular design and synthesis, excellent photophysical properties, superior redox stability, and highly efficient emissions of virtually all colors. Here, recent progress on new material design, regarding photo- and electroluminescence is highlighted, including several interesting topics such as: i) color-tuning strategies of cationic iridium(III) complexes, ii) widespread utilization in phosphorescent light-emitting devices fabricated by not only solution processes but also vacuum evaporation deposition, and iii) potential applications in data record, storage, and sercurity. Results on anionic iridium(III) complexes and "soft salts" are also discussed, indicating a new related subject. Finally, a brief outlook is suggested, pointing out that ionic iridium(III) complexes should play a more significant role in future organic electronic materials technology.

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In patients with obstructive sleep apnea syndrome (OSAS), the blood coagulation system may contribute to an increased risk of cardiovascular events, which occur most frequently in the morning. Nasal continuous positive airway pressure (NCPAP) treatment can improve the mortality of patients with OSAS. We measured the plasma fibrinogen concentration, which is an independent risk factor for cardiovascular events, in the afternoon (3:30 P.M.) and the next morning upon awakening (8:30 A.M.) in 11 patients with OSAS (apnea and hypopnea index > 20) before and after NCPAP therapy. We also measured the hematocrit, the C-reactive protein, and the total plasma protein at the same time. The plasma fibrinogen and hematocrit levels in the morning (298 +/- 16 mg/dl and 48.5 +/- 1.5%, mean +/- SEM) were significantly higher than on the previous afternoon (275 +/- 14 mg/dl and 46.6 +/- 1.3%) (fibrinogen, p < 0.02; hematocrit, p < 0.005). The whole blood viscosity (WBV) at a shear rate of 208 inverse seconds, which can be predicted based on the hematocrit and total plasma protein, was also significantly higher in the morning (4.98 +/- 0.20/s) than in the afternoon (4.73 +/- 0.17/s) (p < 0.005). These increases in the plasma fibrinogen concentration and the WBV in the morning disappeared after NCPAP treatment. The attenuation of morning increases in the plasma fibrinogen concentration and WBV induced by NCPAP treatment may contribute to an overall improvement in the mortality from cardiovascular events in patients with OSAS.

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Yb(3+) ions with various site symmetries have been observed in the absorption and emission spectra of Yb(3+):CaF(2) crystals, both γ-irradiated and annealed in hydrogen. The absorption intensity value is found to be much higher for the γ-irradiated crystal and strongly dependent on the gamma dose. The UV absorption spectra of γ-irradiated and H(2)-annealed CaF(2):5 at.% Yb(3+) crystals are quite similar. Yb(2+) absorption bands are observed at 360, 315, 271, 260, 227 and 214 nm, which are called A, B, C, D, F and G bands, respectively. For γ-irradiated CaF(2):30 at.% Yb(3+), an additional band at 234 nm can be seen. It is suggested that only a negligible amount of Yb(3+) ions are converted into Yb(2+) under the γ-irradiation. The presence of Yb(2+) is confirmed by the 565 and 540 nm luminescence under 357 nm excitation. It is also suggested that the excitation in the A, C, D and F absorption bands of Yb(2+) gives rise to photo-ionization of Yb(2+) ions and electrons in the conduction band to form the excited Yb(3+) ions which emit IR Yb(3+) luminescence.The UV absorption and emission spectra obtained for γ-irradiated and H(2)-annealed crystals have different structures. This suggests that different mechanisms are responsible for the creation of Yb(2+) ions. γ-irradiation favours Yb(2+) isolated centres by reduction of Yb(3+) ions located at Ca(2+) lattice sites, whereas annealing in hydrogen favours Yb(2+) centres neighbouring Yb(3+) ions when a Yb(3+) ion pair captures a Compton electron. Also, γ-irradiation does not change the position of Yb(3+) ions converted into Yb(2+) in the CaF(2) lattice. In the case of H(2) annealing, a Yb(3+) ion converted to Yb(2+) is shifted to the Ca(2+) position in the lattice.

The self-activated yellow-emitting phosphors of vanadates Ca5M4(VO4)6 (M = Mg, Zn) were synthesized via the solid-state reaction route. The formation of single phase compound with garnet structure was verified through X-ray diffraction (XRD) studies. The excitation and emission spectra and the thermal quenching of luminescence intensities were measured. The different luminescence properties of Ca5Mg4(VO4)6 and Ca5Zn4(VO4)6 phosphors were presented, e.g., the spectra shift, the luminescence lifetimes, the absolute quantum efficiency, the color coordinates and the Stokes shift. This deference was discussed on the base of the relationship between the micro-structure and the charge transfer transitions in [VO4]3- groups in the lattices. Ca5Mg4(VO4)6 could be suggested to be a potential yellow-emitting phosphor for the application on near-UV excited white LEDs.

Color-saturated green-emitting molecules with high Commission Internationale de L’Eclairage (CIE) y values have great potential applications for displays and imaging. Here, we linked the outer phenyl groups in multiple-resonance (MR)-type blue-emitting B (boron)-N (nitrogen) molecules through bonding and spiro-carbon bridges, resulting in rigid green emitters with thermally activated delayed fluorescence. The MR effect and multiple interlocking strategy greatly suppressed the high-frequency vibrations in the molecules, which emit green light with a full-width at half-maximum of 14 nm and a CIE y value of 0.77 in cyclohexane. These were the purest green molecules with quantum efficiency and color purity that were comparable with current best quantum dots. Doping these emitters into a traditional green-emitting phosphorescence organic light-emitting diode (OLED) endowed the device with a Broadcast Service Television 2020 color-gamut, 50% improved external quantum efficiency, and an extremely high luminescence of 5.1 × 105 cd/m2, making it the greenest and brightest OLED ever reported.

Eu 3+ doped red-emitting phosphors of double phosphates Ca 9 R(PO 4 ) 7 (R ¼ Al, Lu) were synthesized by a general high temperature solid-state reaction. The phosphors were characterized by X-ray powder diffraction (XRD). The detailed luminescence properties, e.g., the emission spectra under the excitation of UV light, the photoluminescence excitation spectra and decay lifetimes were reported. The phosphors can be efficiently excited by near UV light to realize an intense red luminescence (613 nm) corresponding to the electric dipole transition 5 D 0 / 7 F 2 of Eu 3+ ions. The luminescence properties and the potential applications were analyzed. These phosphors were investigated by the site-selective emission spectra and the fluorescence decay curves in the 5 D 0 / 7 F 0 region using a pulsed, tunable, narrowband dye laser. It is suggested that Eu 3+ ions have three different crystallographic sites doped in Ca 9 Al(PO 4 ) 7 , and five sites in Ca 9 Lu(PO 4 ) 7 host. The site assignments of Eu 3+ ions in Ca 9 R(PO 4 ) 7 (R ¼ Al, Lu) were discussed on the base of both optical spectroscopy results and structural analysis.