Structure, photochromic, and electrochemical properties of dioctadecylamine/H3PMo12O40 Langmuir–Blodgett film

We used the Langmuir–Blodgett (LB) technique to construct a well-defined and structure-controllable photochromic material—a highly ordered multilayer film composed of dioctadecylamine and 12-molybdophosphoric acid (PMo12). We identified well-ordered lamellar structures using X-ray diffraction, polarized IR, and Raman spectra, and we determined a packing model of the two components in the LB film. We found the Keggin structure and fundamental features of the PMo12 ion to be maintained in the hybrid film. This hybrid LB film displayed photochromic properties upon UV light irradiation and we observed the following process from first-order kinetics. The photochromism exhibited the ability to switch between colorless and blue. A fading process occurred when the film was exposed to ambient air or O2 in the dark. During the color change, the packing structure of the film was well maintained. We also examined the electrochemical behavior of the hybrid LB film by cyclic voltammetry in detail and we propose different kinetic mechanisms for the film before and after irradiation.

We construct a highly ordered multilayer film composed of dioctadecylamine and 12-molybdophosphoric acid on solid substrate through Langmuir–Blodgett technique. Such a hybrid film displays reversible photochromic property upon UV light irradiation. The electrochemistry of the film proposes different kinetic mechanisms for the film before and after irradiation.Figure optionsDownload as PowerPoint slide