Förster energy transfer from a fluorescent dye to a phosphorescent dopant: a concentration and intensity study

We report on the long-range dipole-dipole Förster energy transfer between a fluorescent dye and a phosphorescent dopant in solid thin films. For our study we used 4,4′-N,N′-dicarbazole-biphenyl as a host and the organometallic complex fac tris(2-phenylpyridine) iridium(III) as a guest. By studying the photoluminescence efficiency of films with various host and guest concentrations and by comparing these results with those obtained from a numerical model, we determine a Förster radius of R0 ∼ 3 nm.