Formation of covalently linked self-assembled films of a functional hyperbranched conjugated poly(phenylene vinylene)

A novel self-assembled (SA) film of a functional dendritic molecule, hyperb ranched conjugated poly(phenylene vinylene) (SPPV), is obtained through the covalent bond linkage on a hydrophilic substrate (e.g., mica). The self-as sembling process of the film is investigated in detail by UV-vis and fluore scence spectroscopy, and the morphology of the films are observed by atomic force microscopy. Hyperbranched molecules require longer times for forming highly ordered and homogeneous molecular films (several days) compared to small molecules. Excimers formed from the excited state of SPPV in these SA films can be detected by their fluorescence properties. The difference of fluorescence properties between the SPPV SA film and spin-coating film show s that the SA film is ordered and homogeneous. Finally, the photovoltic res ponse is reported for these SA films.