Control of optical properties in cyanine dye thin film fabricated by a layer-by-layer method

We report the fabrication of cyanine dye molecule thin films by a layer-by-layer (LBL) method. In the LBL thin film, the photoluminescence properties can be controlled by the separation between the donor and acceptor dye molecule layers. While the distance dependence of the energy-transfer rate changes around 2 nm, which is comparable with the lengths of the molecules, the energy-transfer rate as evaluated from the photoluminescence decay time shows a maximum value of approximately 15 ns(-1). The thin films fabricated by the LBL method will be therefore applicable for ultrafast optical switches with higher repetition rate. (C) 2014 AIP Publishing LLC.