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

Abstract

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.