Characterization of merocyanine 540-octadecylamine thin films fabricated by Langmuir-Blodgett and Spin-Coating techniques.

The present study reports thin films of merocyanine 540–octadecylamine (MC540–ODA) prepared by Langmuir–Blodgett (LB) and Spin–Coating (SC) methods, and their photophysical and morphological features. The addressed MC540–ODA LB films are different from the others designed by co–spreading method. Briefly, a known quantity of ODA in chloroform was slowly spread on the surface of a 10−6 M concentrated solution of MC540 in deionized water as subphase and the LB films were generated by the deposition of a MC540–ODA Langmuir film onto a solid substrate. The capability of MC540–ODA forming a stable monolayer at the air-water interface was confirmed by pressure–area (π–A) isotherm studies. The spectroscopic studies revealed that the photophysical properties of LB films strongly depended on the number of layers and deposition pressure. The SC thin films of MC540 at a constant dye concentration with and without ODA were successfully fabricated under the optimized experimental conditions. In the SC thin films, ODA molecules played a crucial role in their photophysical and morphological variations. Consequently, the varied experimental route allows to fine–tune the photophysical and morphological properties of the dye thin films. Image 1 • Langmuir-Blodgett and Spin-Coating films of MC540-ODA were fabricated. • The formation of H-dimers and H-aggregates depended on the film conditions. • MC540 LB films showed the large, overlapped and folded layers in AFM image. • The bowl and island-like nanostructures of MC540 SC films were monitored by AFM. [ABSTRACT FROM AUTHOR]