We observed unusual radiative decay characteristics of a (fac-tris(2-phenylpyridine)iridium [Ir(ppy)3]) triplet-excited state doped into 4,4′-N, N′-dicarbazole-biphenyl (CBP) and polymethylmethacrylate (PMMA) host matrices. From a measurement of the temperature dependence on the phosphorescence intensity and the lifetime of Ir(ppy)3 in these hosts, we observed that phosphorescence intensities are independent of temperature, while the lifetimes significantly increase at temperatures below T ∼ 50 K. These results lead us to conclude that the non-radiative transition rate (knr) from the triplet excited state is very small compared with the radiative transition rate (kr) and that the phosphorescence quantum yield (øPH) is nearly 100% even at room temperature. Based on our experimental results, we propose a possible decay mechanism to rationalize the characteristic temperature dependence on the transient phosphorescence.
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Issue number||7 A|
|Publication status||Published - Jul 1 2004|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)