Dynamic morphology of mesoscopic pseudoisocyanine J aggregates on mica induced by humidity treatments
نویسندگان
چکیده
The effect of humidity treatments on the surface morphology of spin-coated pseudoisocyanine (PIC) dye films on mica was investigated by absorption spectroscopy, fluorescence microscopy, and atomic force microscopy (AFM). We demonstrated that the humidity treatment caused dynamic changes of mesoscopic J aggregate morphology due to the mobile nature of PIC molecules on mica surface. Under dry condition, lots of microcrystalline PIC J aggregates were isolatedly distributed on mica. In a low-humidity treatment (32% relative humidity (RH)), characteristic branch-like and patchy leaf-like J aggregate islands could be observed together with non-emissive disordered aggregates. The J aggregate islands grew to possess large patchy leaf-like morphology in a high-humidity treatment of 65% RH. The mobile properties of PIC on a mica surface under humid environments can be explained by capillary condensation of water around hydrophilic microcrystals on the surface and consequent disjoining pressure. © 2004 Elsevier B.V. All rights reserved.
منابع مشابه
Room-Temperature Fluorescence Lifetime of Pseudoisocyanine (PIC) J Excitons with Various Aggregate Morphologies in Relation to Microcavity Polariton Formation
The results of room-temperature fluorescence lifetime measurements are reported for the excitation of J aggregates (Js) of pseudoisocyanine chloride (PIC-Cl) prepared in potassium polyvinyl sulfate (PVS) polymer thin films, their aqueous solutions, and NaCl aqueous solutions. Variations of the microscopic morphologies of the aggregates were investigated. The results show that fluorescence decay...
متن کاملExciton Dephasing and Thermal Line Broadening in Molecular Aggregates
Using a model of Frenkel excitons coupled to a bath of acoustic phonons in the host medium, we study the temperature dependence of the dephasing rates and homogeneous line width in linear molecular aggregates. The model includes localization by disorder and predicts a power-law thermal scaling of the effective homogeneous line width. The theory gives excellent agreement with temperature depende...
متن کاملOptical and Resonant Non-Linear Optical Properties of J-Aggregates of Pseudoisocyanine Derivatives in Thin Solid Films
متن کامل
The role of cellulose acetate as a matrix for aggregation of pseudoisocyanine iodide: absorption and emission studies.
Films of pseudoisocyanine iodide in a cellulose acetate matrix were prepared by spin coating and characterized by UV/Vis absorption and fluorescence spectroscopies. The comparison with self-supported films of the same dye enabled analysing the role of the matrix in the aggregation of pseudoisocyanine iodide ([PIC]I). It was proved that cellulose acetate is a suitable support for [PIC]I J-aggreg...
متن کاملFormation of pseudoisocyanine J-aggregates in poly(vinyl alcohol) fibers by electrospinning.
Submicrometer diameter, light emitting fibers of poly(vinyl alcohol) (PVA) doped with pseudoisocyanine (1,1'-diethyl-2,2'-cyanine bromide, PIC) dye were prepared by electrospinning. A horizontal setup was employed with a stationary collector consisting of two parallel-positioned metal strips separated by a void gap. Formation of uniaxially aligned and randomly deposited fibers in electrospun fi...
متن کامل