Electrophile........

we can slao say that Si has partial +ve charge due to high electronegativity of F.

I don't think Si has d-orbital ...........

Si,z=14,
1s²,2s²,2p⁶,3s²,3p²

has a vacant d-orbital dat can accept electrons

This implies oxygen has also vacant d-orbital...................??.......

Oxygen, nitrogen and fluorine are at the beginning of their respective groups and hence have no vacant d-orbitals. Kindly refer to the chapter "p-Block Elements" in NCERT XII.
It would do you good if you actually read your theory before you came here with doubts, because such basic things are already dealt with in textbooks.