Facile assembly of polyoxometalate-polyelectrolyte films on nano-MO2 (M = Sn, Ti) for optical applications

Abstract

The polyoxometalate [PMo12O40] 3-(POM) has been deposited onto high surface area nano-SnO2 using a polycation. The POM surface coverage recorded was approximately 17 times higher than that achieved on planar substrates using the same method, reducing considerably the time needed to assemble conducting films suitable for optical applications such as electrochromism. The immobilisation of the analogous tungstate [PW12O40] 3onto a nano-TiO2 semiconductor electrode demonstrates the versatility of this approach, and underscores potential applications using a large combination of polyoxomolybdates or polyoxotungstates with various metal oxide films.

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

“…Upon the modulation of the electron donating and withdrawing groups in molybdenum‐based polyoxometalates, the spacer group, the Lindqvist structure and the –NH 2 group are proposed to be important for the p‐type dye‐sensitized solar cells performance . Attaching [PMo 12 O 40 ] 3− on metal oxide substrate has been attempted for similar optoelectronic applications . The chemisorption of light‐harvesting molybdenum cluster on TiO 2 and NiO could lead to electron/hole transfer either from the cluster to the substrate or the reverse direction .…”

“…[255][256][257] Attaching [PMo 12 O 40 ] 3− on metal oxide substrate has been attempted for similar optoelectronic applications. 258 The F I G U R E 7 Schematic view of the proposed atomic representation of the interactions between polyoxometalate and the sulfur species by leveraging the Lewis acidic and basic sites in the polyoxometalate to anchoring Li 2 S n moieties in lithiumsulfur batteries. Reproduced with permission from Ye et al 226 Copyright ACS (2018) 226 [Colour figure can be viewed at wileyonlinelibrary.com] chemisorption of light-harvesting molybdenum cluster on TiO 2 and NiO could lead to electron/hole transfer either from the cluster to the substrate or the reverse direction.…”

Amino acid appended perylene bisimides: self-assembly, immobilization on nanocrystalline TiO2, and electrochromic properties

“…Scan rate dependent CVs in 0.1 M LiClO4/MeCN showed a linear relationship between scan rate and peak current, in-line with a surface-confined electrochemical response according to Eqn. 1, 16 which can also be used to estimate the geometric surface coverage, Γ, of electroactive PBI:…”

“…24,25,26 Amongst the most commonly used EC materials are oxides such as WO3, 27 and recently a shift towards organic EC materials based mainly on oligothiophene polymers, 28 with materials covering the full palette of colours reported. 29,30 Other materials commonly studied include viologens, 31 metallopolymers based on Ru(II) polypyridyl derivatives, 32 polyoxometalates, 16 Prussian blue, 33 and polyaniline. 34 These materials have the advantage of being fully soluble, hence they can be processed onto surfaces using conventional wet chemistry techniques, rendering them suitable for roll to roll spraying, or printing on flexible conducting substrates.…”

“…13 TiO2 is also increasingly being recognised as an excellent substrate for use with materials exhibiting redox potentials negative of, or close to, the conduction band edge; this has led to the use of TiO2 as an electrode support for CO2 reduction electrocatalysis 14, 15 and electrochromic molecular materials. 16 Adsorption onto nanoparticulate oxide films, such as TiO2, is typically achieved through dip-coating and chemisorption to the surface via carboxylate or phosphonate linkages. PBIs have been immobilised onto various metal oxides (In:SnO2, WO3, Al2O3, NiO, TiO2) for use in fundamental photophysical studies and dyesensitised PEC cells, typically using phosphonate linkers.…”