Platinum Metals Rev., 2003, 47, (2), 60
Red-Light Emission Using Iridium
A team from the National Tsing-Hua University, Taiwan, report a new route to design electroluminescent polymers (X. Chen, J.-L. Liao, Y. Liang, M. O. Ahmed, H.-E. Tseng and S.-A. Chen,J. Am. Chem. Soc., 2003, 125, (3), 636–637). They grafted high-efficiency green Ir(ppy)3 and red btp2Ir(acac) phosphorescent complexes as dopants and carbazole (Cz) charge transport moieties onto alkyl side chains of fully conjugated polyfluorene polymers, for polymer light-emitting diodes (PLEDs).
The fabricated PLEDs emitted red light with high efficiency, 2.8 cd A-1 at 7 V and 65 cd m-2, and can emit broad band light having blue, green and red peaks (2.16 cd A-1 at 9 V). Incorporating Cz significantly increases the efficiency and lowers the turn-on voltage.