(Invited) Hybrid (iso)Porphyrin – Polyoxometalate Copolymer for Photo(electro)Chemical Applications
Authors: Ruhlmann Laurent , Liang Yiming , WANG Jingjing , Badets Vasilica , Bonnefont Antoine 
Published: July 2021

The development of hybrid polymers incorporating polyoxometalates (POMs) is a promising approach to elaborate new functional materials. To expand the practical applications, their association to a visible-light photosensitizer is needed.

In this context, we have developed a method of electropolymerization of POMs based on nucleophilic attack onto the electrogenerated porphyrin dications.
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The formation of hybrid POM-porphyrin copolymeric films (Fig. 1, film I) can be obtained by the electro-oxidation of porphyrin in the presence of the POM bearing two pyridyl groups (Py-POM-Py)
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. This process is feasible for various type of POMs such as Dawson, Lindqvist or Keggin type POMs
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. Stable 1D isoporphyrin
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– POM or 3D isoporphyrin – PIM copolymers (PIM = PolyIodoMetalate; Fig. 2) have been also develop recently showing interesting efficiency even upon the NIR illumination.

A second methodology is also proposed to form hybrid POM-porphyrin films (Fig. 1, films II or III): first the formation of cationic polyporphyrin electropolymer. Then, by metathesis reaction, the (partial) exchange onto the surface of the initial counter ions by the POMn- or by the nanoparticles stabilized with POMn- (POMn-@M, M = Ag, Au, Pt, etc.).
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The photovoltaic performances of these hybrid materials have been investigated by photocurrent transient measurements under visible-light illumination
9-11
given by now good efficiency. In order to increase the efficiency, mesoporous ITO electrodes (nanofiber formed by electrospun or porous ITO electrode obtained using a colloidal co-assembly approach) have been used and will be discussed (Fig. 2).

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Figure 1