Poly(9-vinylcarbazole) (PVK) is a typical hole-transporting polymer and is often used as a host in electroluminescence devices.In this paper

Frster energy transfer from organic molecules (PVK) to inorganic nanoparticles (SiO

2

) was discussed. SiO

2

nanoparticles

which are confirmed to be 60nm using transmission electron microscope (TEM)

have been synthesized by sol. The structure scheme of poly (9-vinylcarbazole) (PVK) molecule is shown firstly. The emission of luminescence is the result from π

*

-π transition of π electrons. Photoluminescence (PL) spectra of the PVK/SiO

2

composite film on Si substrates were employed to study the interface effect. In the PL spectra of PVK molecules

three obvious peaks (417

458

495nm) can been seen. The emission of 417nm comes from free exciton. The emission of 458nm comes from bound exciton. And the emission around 495nm is correlated to surface defect states. The intensity of short-wavelength emission (about 400nm) is higher than that of visible luminescence (about 495nm). Two luminescence peaks can be observed in the PL spectra of 60nm SiO

2

nanoparticles. In contrast to the PL spectra of PVK molecules

the luminescence intensity about 495nm is higher than that about 400nm in SiO

2

nanoparticles PL spectra. Furthermore

UV/Visible absorption spectroscopy of 60nm SiO

2

nanoparticles was measured. The spectrum indicates that the scale of absorption is wide enough from 200nm to 500nm. The ratio of PVK to SiO

2

in the composite was increased orderly in weight. In the PL spectra of different concentration composite films

we found that Frster energy transfer occurred between PVK and SiO

2

nanoparticles. Overlap is observed between the UV-Visible absorption spectrum of the SiO

2

nanoparticles and the emission spectrum of PVK molecules. We suggest that this overlap is the necessary condition of Frster energy transfer. Further investigation indicates that 40% (the content of PVK in composite in weight) is regarded as an optimized content for Frster energy transfer from PVK molecules to SiO

2

nanoparticles. The reason maybe is the surfaces of SiO

2

nanoparticles are modified successfully and the disperse of SiO

2

nanoparticles is unified in this concentration.