Charge percolation in redox-active thin membrane hybrids of mesoporous silica and poly(viologens)

Abstract

Charge transport via the electron-hopping mechanism was studied in redox-active films of mesoporous silica infiltrated by oligomeric and molecular viologens.

Zinc porphyrin/mesoporous titania thin film electrodes: a hybrid material nanoarchitecture for photocatalytic reduction

“… 45 Hence, reduction of MV 2+ acts as a proof of concept for H 2 production. It is worth mentioning that poly(viologens) in solution are able to diffuse through the MTTF porous structure, 46 enabling the use of MTTF pores as photocatalytic nanoreactors.…”

Polyaniline nanowire arrays generated through oriented mesoporous silica films: effect of pore size and spectroelectrochemical response

“…[39][40][41] When functionalized with redox-active moieties, the vertical nanochannels become an area of unidirectional charge transfer by long-range electron hopping through the insulating silica membrane, 35,[42][43][44][45] with more effective charge percolation than on other types of mesostructures. 46 Finally, such oriented mesoporous silica lms are attractive hosts for the connement of reagents (nano-objects, nano-sized materials or supramolecular assemblies). 44,47,48 They are also, in principle, ideal hard templates for the growth of nanolaments with ultra-small diameters, but this is quite challenging, as demonstrated for metal nanowires electrodeposition, for instance.…”

A Comparative Study of PMETAC-Modified Mesoporous Silica and Titania Thin Films for Molecular Transport Manipulation

“…Previous works using PMETAC-modified mesoporous silica thin films with variable polymer content had shown that a gradual variation of ionic permselectivity can be tuned for increasing PMETAC loadings within the mesopores. The interplay between silanol sites and PMETAC groups leads to a complex transport behavior, which has to take into account electrostatic factors such as exclusion or preconcentration [41], as well as specific adsorption of electroactive species on the pore surface that might lead to a percolative hopping pathway [37,48]. Figure 5 shows typical CV results of the negatively or positively electrochemical probes [(Fe(CN) 6 ] 3-) and [Ru(NH 3 ) 6 ] 3+ , respectively [49].…”