Excitation energy transfer between tris-(8-hydroxyquinoline) aluminum and a red dye

Excitation energy transfer between tris-(8-hydroxyquinoline) aluminum (Alq(3)) and a red dye 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) has been investigated by means of in situ measurements of photoluminescence (PL) of bilayer Alq(3)/DCM films with various Alq(3) thicknesses. It is found that exciton diffusion in Alq(3) and Forster energy transfer from Alq(3) to DCM are contributive to the PL spectra measured. A rate equation model based on these two processes is derived and used to fit experimental results. The Forster energy transfer radius obtained for the system is R-0=3.3 +/- 0.1 nm. Energy transfer in the blend system is also analyzed based on the model.