Measurement of photoluminescence efficiency of Ir(III) phenylpyridine derivatives in solution and solid-state films

We compared the photoluminescence efficiency (Phi(PL)) of fac-tris(2-phenylpyridine) iridium (Ir(ppy)(3)) and derivatives of it in solution and in doped solid-state films and estimated their radiative and nonradiative decay rates. The green phosphor of Ir(ppy)(3) and blue phosphors of FIrpic, Ir(Fppy)(3), FIr6 showed high Phi(PL) values approaching to 100% in both solution and doped solid-state films. On the other hand, the red phosphor of Btp(2)Ir(acac) showed lower Phi(PL) value less than 40% in both environments. Photoacoustic spectroscopy results indicated that for Btp(2)Ir(acac) nonradiative decay from the triplet state to the ground states is 64 +/- 8%. (C) 2008 Elsevier B.V. All rights reserved.