By combining the iridium(III) ppy-type complex (Hppy=2-phenylpyridine) with a square-planar platinum(II) unit, some novel phosphorescent oligometallaynes bearing dual metal centers (viz. Ir(III) and Pt(II)) were developed by combining trans-[Pt(PBu(3))(2)Cl(2)] with metalloligands of iridium possessing bifunctional pendant acetylene groups. Photophysical and computational studies indicated that the phosphorescent excited states arising from these oligometallaynes can be ascribed to the triplet emissive Ir(III) ppy-type chromophore, owing to the obvious trait (such as the longer phosphorescent lifetime at 77 K) also conferred by the Pt(II) center. So, the two different metal centers show a synergistic effect in governing the photophysical behavior of these heterometallic oligometallaynes. The inherent nature of these amorphous materials renders the fabrication of simple solution-processed doped phosphorescent organic light-emitting diodes (PHOLEDs) feasible by effectively blocking the close-packing of the host molecules. Saliently, such a synergistic effect is also important in affording decent device performance for the solution-processed PHOLEDs. A maximum brightness of 3,356 cd m(-2) (or 2,708 cd m(-2)), external quantum efficiency of 0.50% (or 0.67%), luminance efficiency of 1.59 cd A(-1) (or 1.55 cd A(-1)), and power efficiency of 0.60 Lm W(-1) (or 0.55 Lm W(-1)) for the yellow (or orange) phosphorescent PHOLEDs can be obtained. These results show the great potential of these bimetallic emitters for organic light-emitting diodes.

Promoting triplet energy-transfer in novel phosphorescent polymers with platinum(II) polymetallayne backbones to achieve high EL performances with η L of 11.49 cd A -1 , η ext of 4.38% and η P of 3.78 lm W -1 . Abstract:Two series of new phosphorescent copolymers with bicarbazole-based platinum(II) polymetallayne backbone have been successfully prepared through Sonogashira cross-coupling with different Ir III ppy-type (ppy=2-phenylpyridine anion) complexes as phosphorescent centers.The photophysical investigations not only indicate highly efficient triplet energy-transfer process from the polymetallayne segments to the phosphorescent units in the polymer solution, but also figure out the structure-property relationship between the triplet energy-transfer process and the energy-levels of different excited states. In addition, the phosphorescent copolymers can furnish yellow-emitting phosphorescent OLEDs (PHOLEDs) with high EL efficiencies with current efficiency ( L ) of 11.49 cd A -1 , external quantum efficiency ( ext ) of 4.38%, power efficiency ( P ) of 3.78 lm W -1 , and red-emitting PHOLEDs with  L of 5.86 cd A -1 ,  ext of 10.1%,  P of 2.29 lm W -1 , representing very decent electroluminescent performances ever achieved by the phosphorescent copolymers. This work herein not only furnishes very important clues for further polishing this category novel phosphorescent polymer, but also provides a new approach to design and synthesis of highly efficient phosphorescent copolymers. phosphorescent polymers. Playing the same role of the host materials in the phosphorescent OLEDs with small molecular triplet emitters, the organic segments in the phosphorescent polymers can act as the host of the phosphorescent blocks. Thus, the emission layer (EML) in PHOLEDs can be easily constructed by directly spin-coating a solution of the phosphorescent polymers, which can greatly simplify the device fabrication. Similar to their fluorescent counterparts, PHOLEDs also relates to the charge carrier injection/transporting in their EMLs.Thus, it seems that the phosphorescent polymers with conjugated backbones are preferred to promote the charge carrier injection/transporting in the EML of PHOLEDs. Another critical issue should be addressed in PHOLEDs based on conjugated phosphorescent polymers is blocking the undesired reverse energy-transfer from the emissive triplet states of the phosphorescent units to the non-emissive triplet states of the conjugated backbones in the phosphorescent polymers. 5 In order to achieve high EL performance in PHOLEDs, the reverse energy-transfer process should be restrained as far as possible. With the aim to fulfill this purpose, increasing the triplet energy level of the backbones of phosphorescent polymers should be a feasible way. Hence, the phosphorescent polymers with nonconjugated backbones have also been prepared. Clearly, this type polymer backbone seems unfavorable for charge carrier injection/transporting. In order to overcome the weakness associated with the nonconjugated backbones ...

Novel phosphorescent polymers are developed with platinum(ii) polymetallayne-based backbones bearing functionalized IrIII phosphorescent units to promote highly efficient triplet state energy-transfer and achieve high EL performances.

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