title: Suppressing Structural Colors of Photocatalytic Optical Coatings on Glass: The Critical Role of SiO2.
abstract: The appearance of structural colors on coated-glass is a critical esthetical drawback toward industrialization of photocatalytic coatings on windows for architecture or automobile. Herein we describe a rational approach to suppress the structural color of mesoporous TiO2-based coatings preserving photoactivity and mechanical stiffness. Addition of SiO2as third component is discussed. TixSi(1-x)O2mesoporous coatings were fabricated by one-step liquid deposition process through the evaporation induced self-assembling and characterized by GI-SAXS, GI-WAXS, electron microscopies, and in situ Environmental Ellipsometry Porosimetry. Guided by optical simulation, we investigated the critical role of SiO2on the optical responses of the films but also on the structural, mechanical, and photocatalytic properties, important requirements to go toward real applications. We demonstrate that adding SiO2to porous TiO2allows tuning and suppression of structural colors through refractive index matching and up to 160% increase in mechanical stiffening of the films. This study leads us to demonstrate an example of "invisible" coating, in which the light reflection is angle- and thickness-independent, and exhibiting high porosity, mechanical stiffness, and photoactivity.
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005 Paris, France.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005 Paris, France.|Institute for Materials Chemistry and Engineering, Kyushu University , 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan.
authors.forename: Mickael
authors.initials: M
authors.lastname: Boudot
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005 Paris, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Boissière
authors.affiliation: IM2NP, Faculté des Sciences et Techniques , Campus de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13397 Marseille, France.
authors.forename: David
authors.initials: D
authors.lastname: Grosso
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005 Paris, France.
authors.forename: Marco
authors.identifier: http://orcid.org/0000-0002-6254-5116
authors.initials: M
authors.lastname: Faustini
keywords: interference; mesoporous; optical coatings; photocatalytic; structural color