Complex Langmuir−Blodgett Films of SiO₂ and ZnO Nanoparticles with Advantageous Optical and Photocatalytical Properties

Abstract

Multifunctional Langmuir-Blodgett (LB) films were fabricated on the surface of glass substrates using sol-gel derived ZnO and SiO2 particles. ZnO particles of 6 and 110 nm diameter were synthesized according to the methods of Meulenkamp and Seelig et al. (Meulenkamp, E. A. J. Phys. Chem. B 1998, 102, 5566; Seelig, E. W.; Tang, B.; Yamilov, A.; Cao, H.; Chang, R. P. H. Mater. Chem. Phys. 2003, 80, 257). Silica particles of 37 and 96 nm were prepared by the Stober method (Stober, W.; Fink, A.; Bohn, E. J. Colloid Interface Sci. 1968, 26, 62). Alternate deposition of monoparticulate Langmuir films of SiO2 and ZnO nanoparticles provided complex (six- and nine-layered) LB films with both antireflective and photocatalytic properties. The LB films were investigated with scanning electron microscopy (morphology and structure) and UV-vis spectroscopy (optical properties and stability). The photocatalytic activity was measured by immersing the UV-irradiated films into an aqueous solution of Methyl Orange and following the photodegradation of the dye by optical spectroscopy. Adding ZnO particles to the silica films slightly lowered the antireflection property but ensured strong photocatalytic activity. Both the photocatalytic activity and antireflection properties were proved to be sensitive to the sequence of the silica and ZnO layers, with optimum properties in the case of nine-layered films with a repeated (SiO2-ZnO-ZnO) structure.

The Langmuir‐Blodgett Approach to Making Colloidal Photonic Crystals from Silica Spheres

“…The LB deposition of multilayers is a relatively rapid process which is well suited for applications that do not require films with a perfect crystalline microstructure. Nagy et al described recently antireflective properties of LB multilayers 63. Presently, we are studying the influence of LB deposition of antireflective coatings onto the efficiency of solar cells based on polycrystalline Si.…”

“…Nagy et al described complex structures made of the sequence of layers of the SiO 2 and ZnO nanoparticles that show both photocatalytic and antireflection properties 63…”

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

“…Antireflective coatings are routinely designed to enhance the light transmission through these surfaces. 15,[32][33][34][35][36][37][38][39][40][41][42] However, antireflective coatings on flexible substrates are still rare. 32 An antireflective coating is based on destructive interference between the reflected light from the air/ film and the substrate/film interfaces.…”

FABRICATION OF UNIFORM AND COMPACT ZnO THIN FILMS BY LANGMUIR–BLODGETT METHOD

“…28,29 Nagy et al synthesized multifunctional LB¯lms on the surface of glass substrates using solÀgel derived ZnO and SiO 2 particles, and found that LB method was an e±cient technique for the tailoring of complex layer structures. 30 Ikegami et al demonstrated the formation of ionic bonds between a fatty-acid of LB monolayer and a ZnO-based transparent electrode used as a substrate, which might lead to a new way of obtaining functional organicÀinorganic nanosystems. 31 Wang and Wee deposited smooth and homogeneous monolayer silicalite seeds on silicon substrate surface using LB method, noting that the seed layers were the important paramount of the thickness, smoothness and continuity of monolayer.…”