Mesoporous Bragg Stack Color Tunable Sensors

Abstract

Herein we report a novel self-assembly synthesis, structural and optical characterization of mesoporous Bragg stacks (MBS) composed of spin-coated multilayer stacks of mesoporous TiO(2) and mesoporous SiO(2). Investigation of the optical response of MBS to the infiltration of alcohols and alkanes into its pores reveals better sensitivity and selectivity than conventional Bragg reflectors. Furthermore, we demonstrate that the chemical sensing ability can be tuned via layer thickness, composition and surface properties.

Tunable structural color in organisms and photonic materials for design of bioinspired materials

“…Inorganic porous films using this principle can be used in a color-tunable sensor. Their mesoporous SiO 2 and TiO 2 multilayers can be fabricated by depositing precursor solutions by spin coating [41], dip coating [42] and layer-by-layer assembly [43].…”

Photon Management in Dye Sensitized Solar Cells

“…This might have a deleterious effect on charge transport and recombination through the cell. Very recently, new types of one-dimensional photonic crystals (1DPC) have been prepared by alternate deposition of either mesoporous (Choi et al, 2006); (Fuertes et al, 2007) or nanoparticles (Wu et al, 2007); (Colodrero et al, 2008) based films. These structures Mihi & Míguez, 2005) are usually easier to build and integrate than those abovementioned of higher dimensionality and present attractive features, such as very intense and wide Bragg reflections and reduced thickness (less than a micron versus the several micron thickness of opals).…”

Printing of Large‐Scale, Flexible, Long‐Term Stable Dielectric Mirrors with Suppressed Side Interferences

“…For some years, his research seemed to run out of the focus in of the scientific community, while it was in 2006 and during the growing interest in fiber Bragg gratings, when Choi et al presented optical sensing of solvents via colloidal nanoparticle suspension based dielectric mirrors. [14,15] Their fabrication method suffered from two drawbacks compared to the previously reported technique: high calcination temperatures of 300 °C after each layer deposition and demonstrating maximum only three double layered stacks (≈55% reflectance at λ 0 ≈ 520-640 nm). Through steady progress within the group of H. Míguez, they were able to reduce the annealing temperature of nanoparticle-based dielectric mirrors (three double layers of SiO 2 and TiO 2 , maximum reflectance of 70-80% at λ 0 ≈ 400-800 nm, or ten double layers of SiO 2 and ZrO 2 , maximum reflectance of 80% at λ 0 ≈ 230-320 nm) again down to room temperature in 2009/2010.…”