ATOMIC-FORCE MICROSCOPY OBSERVATION OF CYANINE DYE J-AGGREGATES ON AGBR MICROCRYSTALS GROWN IN GELATIN

The morphology of thiacarbocyanine and oxacarbocyanine dye J-aggregate s adsorbed on (001) surfaces of AgBr microcrystals grown in gelatin wa s observed by atomic force microscopy. No residue of fibrous gelatin w as found on the specimen. The cyanine dyes grew in islands or stripes by means of the Volmer-Weber growth mode, rather than by monolayer ads orption. The thickness of stripes varied from 0.5 nm (monolayer) to 30 nm, and the stripes were constructed of many rectangles [20 x (35-50) nm]. The rectangles were regarded as elementary crystallites or J-agg regate particles photoelectrically separated from one another.