Energy transfer in dye-doped mesostructured composites

Energy transfer between the organic laser dyes coumarin 485 and pyrromethene 567 was investigated in mesostructured silica/block copolymer thin films. The 2-D hexagonal mesostructured silica thin films were made using acidic sol-gel synthesis with poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), (EO20PO70EO20) as the structure-directing agent. The dyes were doped into the film synthesis solutions so that they underwent co-assembly with the silica and block copolymer. At a very low concentration of acceptor, one acceptor molecule for every 20 donor molecules, the donor's emission was drastically quenched, suggesting efficient energy transfer. Investigations into amplified spontaneous emission revealed that the donor/acceptor system resulted in full gain narrowing at significantly lower concentrations than systems without a donor.