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 intensity of five dendritic macromolecules. The emission efficiency decreases with increasing pressure in all cases, but to a greater extent for the larger dendrimers. An explanation is given in terms of changing efficiency of Forster energy transfer. The efficiency is expressed in terms of an effective “Forster distance” R0, a parameter that depends on the overlap between the donor emission and acceptor absorption. From the peak shifts, it appears that R0 decreases significantly with pressure, and an argument is given to explain why this decrease is more important for the larger dendrimers.