Effect of pressure on the emission efficiencies of a series of phenylacetylene dendrimers

The effect of pressure to 60 kbar has been measured on the emission intensi ty of five dendritic macromolecules. The emission efficiency decreases with increasing pressure in all cases, but to a greater extent for the larger d endrimers. An explanation is given in terms of changing efficiency of Forst er energy transfer. The efficiency is expressed in terms of an effective "F orster distance" R-0, a parameter that depends on the overlap between the d onor emission and acceptor absorption. From the peak shifts, it appears tha t Ro decreases significantly with pressure, and an argument is given to exp lain why this decrease is more important for the larger dendrimers.