Control over exciton confinement versus separation in composite films of polyfluorene and CdSe nanocrystals

Composite films of polyfluorene derivative poly(9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl) and cadmium selenide nanocrystals were investigated using photomodulation spectroscopy exciting only the nanocrystal phase. Efficient charge separation resulting in hole injection into the polymer was observed in films in which the nanocrystals had been stripped of surface trioctylphosphine oxide passivating groups. The resulting induced absorption band …