Unconventional Photocatalysis in Conductive Polymers: Reversible Modulation of PEDOT:PSS Conductivity by Long-Lived Poly(Heptazine Imide) Radicals.

Aleksandr Savateev,Christoph M Schüßlbauer,Markus Antonietti,Dirk M Guldi,Yevheniia Markushyna,Tobias Ullrich

doi:10.1002/anie.202014314

Abstract

In photocatalysis, small organic molecules are converted into desired products using light responsive materials, electromagnetic radiation, and electron mediators. Substitution of low molecular weight reagents with redox active functional materials may increase the utility of photocatalysis beyond organic synthesis and environmental applications. Guided by the general principles of photocatalysis, we design hybrid nanocomposites composed of n‐type semiconducting potassium poly(heptazine imide) (K‐PHI), and p‐type conducting poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the redox active substrate. Electrical conductivity of the hybrid nanocomposite, possessing optimal K‐PHI content, is reversibly modulated combining a series of external stimuli ranging from visible light under inert conditions and to dark conditions under an O2 atmosphere. Using a conductive polymer as the redox active substrate allows study of the photocatalytic processes mediated by semiconducting photocatalysts through electrical conductivity measurements.

Highlights

Semiconductor photocatalysis has been extensively studied in the area of water splitting,[1] conversion of CO2,[2] environmental applications,[3,4] and in the synthesis of fine organic molecules.[5,6] In all of these applications, the modus operandi involves the excitation of the semiconductor with a photon of sufficient energy followed by the quenching of the hole and electron with suitable electron donors and acceptors, C
For high-throughput tests a series of K-PHI:PEDOT:PSS blends with different content of K-PHI ranging from 0 to 77.6 wt % were prepared followed by drop casting them between two electrically isolated areas of FTO electrodes and drying in air (Supporting Information, Figures S1–S5)
Hybrid nanomaterials composed of K-PHI nanoparticles and the conductive PEDOT:PSS matrix were prepared by a straightforward method

Summary

Introduction

Semiconductor photocatalysis has been extensively studied in the area of water splitting,[1] conversion of CO2,[2] environmental applications,[3,4] and in the synthesis of fine organic molecules.[5,6] In all of these applications, the modus operandi involves the excitation of the semiconductor with a photon of sufficient energy followed by the quenching of the hole and electron with suitable electron donors and acceptors,. Angewandte Chemie International Edition published by Wiley-VCH GmbH. We integrate two materials, that is, p-type conductive polymer PEDOT:PSS, on one hand, and n-type visible-light responsive carbon nitride semiconductor (K-PHI), on the other hand, into a hybrid nanocomposite: K-PHI:PEDOT:PSS (Figure 1). K-PHI:PEDOT:PSS to visible light under O2-free conditions and to the dark under O2 conditions leads to the reversible doping of PEDOT:PSS that is registered as a change of the composite electrical conductivity. Instead of enabling a chemical reaction between small organic molecules, we use photocatalysis to tune the physicochemical properties of conductive polymers

Results and Discussion

Conclusion

Conflict of interest