Temperature dependence of the singlet excited state lifetime in alq3

The temperature dependence of the lifetime of the singlet excited state in thin films of tris(8-hydroxyquinoline) aluminum (Alq3) is investigated. An increase in the excited state lifetime and fluorescence quantum yield with decreasing temperature from 300K to 77K is observed. A diffusion based singlet exciton trapping model is used to explain these results.