MULTIPLIED MONOLAYER ASSEMBLY OF J-AGGREGATES OF SQUARYLIUM DYE WITH SHORT ALKYL CHAINS

The first observation of J-aggregates of squarylium dyes with short alkyl chains has been made in the monolayer. As the temperature of the aqueous subphase increases, two types of J-aggregates of squarylium dyes with short alkyl chains are formed on the surface and J-aggregates in the monolayer reversibly exchange with each other, depending on the surface pressures and temperatures. In a mixed monolayer with a fatty acid, either an ordinary structure or a multiplied structure is formed by controlling surface pressure. The monolayer assembly with a multiplied structure of dyes is formed under higher surface pressure through phase transition and successively transferred to solid substrates by the Langmuir-Blodgett technique. The multiplied structure of the mixed monolayer is characterized as a triple layer of J-aggregates of squarylium dyes stabilized with a fatty acid monolayer by π-A isotherms, spectroscopic measurements and X-ray diffraction.