The intermolecular interaction and complex of various molecules can influence their optical and electrical properties

especially

efficiency of fluorescence and stability for fluorescent materials. Fluorescence decay experiment can demonstrate energy transfer among molecules and intermolecular interaction. In this paper

Fluorescence decay of the blending of polyvinyl carbazole (PVC) and tris(8-hydroxyquinolinolato) aluminum (Alq) with weight ratio 100:4 and 100:10 were investigated. The decay experiment is pumped by YAG locking-mode laser

whose excitation wavelength is 355nm

and detected by streak camera. Detection wavelength is chose 480nm and 540nm. According to the photoluminescence spectra of PVC and Alq film

these two wavelength correspond to the radiation emission of PVC and Alq respectively. Fiting the decay curve using a single exponential decay function

we get the fluorescent decay time. For the blending ratio 100:4

the decay time is 8.5ns at 460nm and 6.47ns at 540nm. For the blending ration 100:10

it is 7.9ns at 480nm and 5.5ns at 540nm. For Alq film and PVC one

their fluorescent decay time are 16.4ns and 14ns respectively. The blending of PVC and Alq show a evident reduction in fluorescent decay time compared with PVC and Alq. Thus in addition to the energy transfer between PVC and Alq molecules

there is a second channel to exchange energy

and the dynamics in this relaxation can be faster than that of radiation transition. This decay experiment implied that the interaction of PVC and Alq molecules formed a new complex of PVC and Alq

or configuration change of molecule.