Size control of cyanine dye J-aggregates in micrometersized polymer "domes"

The fluorescence behavior of 3,3'-diethyl -9-methylthiacarbocyanine iodide in gm-sized polystyrene droplets, or "domes", on glass substrates was investigated. The samples were prepared by casting dilute polymer/dye solutions onto the substrates. A dewetting process leads to the formation of small polymer domes with a diameter of 1similar to100 mum and a height of 100 nm to several pm. Fluorescence microscopy shows that the dye is incorporated into these polymer domes. The absorption and fluorescence spectra depend on the : size of the polymer domes. Larger domes show red-shifted fluorescence spectra.