Elaboration of Prussian Blue Analogue/Silica Nanocomposites: Towards Tailor-Made Nano-Scale Electronic Devices

Abstract

The research of new molecular materials able to replace classical solid materials in electronics has attracted growing attention over the past decade. Among these compounds photoswitchable Prussian blue analogues (PBA) are particularly interesting for the elaboration of new optical memories. However these coordination polymers are generally synthesised as insoluble powders that cannot be integrated into a real device. Hence their successful integration into real applications depends on an additional processing step. Nanostructured oxides elaborated by sol-gel chemistry combined with surfactant micelle templating can be used as nanoreactors to confine PBA precipitation and organize the functional nano-objects in the three dimensions of space. In this work we present the elaboration of different CoFe PBA/silica nanocomposites. Our synthetic procedure fully controls the synthesis of PBA in the porosity of the silica matrix from the insertion of the precursors up to the formation of the photomagnetic compound. We present results on systems from the simplest to the most elaborate: from disordered xerogels to ordered nanostructured films passing through mesoporous monoliths.

Using Prussian blue analogue nanoparticles confined into ordered mesoporous silica monoliths as precursors of oxides

“…3 shows TEM micrographs of Mono CoCo. No CoCo PBA particle was observed outside the monolith in agreement with the full confinement of PBA particles [38]. The images confirm the 2D-hexagonal organization of the porosity.…”

Magnetism and Photomagnetism of Prussian Blue Analogue Nanoparticles Embedded in Porous Metal Oxide Ordered Nanostructures

“…5 μm thick) cylinder (50-300 nm) 2D hexagonal [46,[49][50][51][52][53][54][55] SiO 2 powder (SBA-15) cylinder (5-7.5 nm) 2D hexagonal [56,57] SiO 2 powder (MCM-41) cylinder (2-3 nm) 2D hexagonal [37,57] SiO 2 powder (MSU) cylinder (2-3 nm) 2D hexagonal and wormlike [58] SiO 2 monolith cylinder (5-6 nm) 2D hexagonal [59] SiO 2 monolith cylinder (5-6 nm) cubic [59] SiO 2 monolith intersheet space (2 nm) lamellar [59] SiO 2 film cylinder (5-6 nm) 2D hexagonal, parallel to the surface [61] SiO 2 film cylinder (3 nm) 2D hexagonal, perpendicular to the surface [60] TiO 2 film perforation (50-80 nm) 2D hexagonal, perpendicular to the surface [62,63] [a] Or lamellar intersheet distance.…”

“…Thus, either by reproducing or by adapting procedures described in the literature, various silica (SiO 2 ) matrices have been prepared to serve as host matrices for the synthesis of PBAs. These are powders generally composed of micrometre-sized grains with 2D hexagonal or wormlike organization of the pores, [37,38,[56][57][58] monoliths with 2D hexagonal, cubic, lamellar or wormlike organization of the pores [39,59] or films with 2D hexagonal organization of channels aligned perpendicular [60] or parallel [61] to the surface of the film. The films with the pores aligned parallel to the surface were obtained by evaporationinduced self-assembly (EISA) combined with spin-coating [61] whereas the films with the pores aligned perpendicular to the surface were obtained by self-assembly combined with electrochemical deposition.…”

“…[37][38][39]56,57,59,61,62,73] With the aim of showing the feasibility of integrating molecular materials into real applications, we are engaged in two directions: the preparation of model components that could be integrated into real devices and the study of the effect of the processing step on the physical properties of the molecular compounds.…”

“…The final material is composed of CoFe PBA nanoparticles (3-4 nm) wrapped in surfactant molecules within the MSU-type silica channels. [58] A different approach was used to prepare CoFe, [59,69] RbCoFe, [39,59,61,69,70] NiCr [59] and NiFe [70] PBA nanoparticles within the surfactant-free ordered mesopores of silica monoliths exhibiting 2D hexagonal, cubic, lamellar and wormlike organizations. Here the solvated metal ion PBA precursor is introduced within the silica channels during the synthesis of the silica matrix.…”