Pd/Pt bimetallic nanoparticles as catalysts in the green synthesis of piconjugated materials for perovskite solar cell applications
Résumé
Thanks to their unique properties (improved volume-to-surface ratio compared to heterogeneous catalysts, high catalytic performance and selectivity…), nanocatalysts[1] are increasingly used for environmental remediation[2] to remove organic pollutants as well as for oxidation-reduction processes and C-C couplings in organic synthesis.[3] Pi-conjugated molecules, which are employed for electronic organic applications, are heavily reliant on palladiumcatalyzed C-C or C-heteroatom couplings for their preparation. Traditional conditions for the catalytic steps usually involve high metal loadings, harmful solvents, and long reaction times at high temperatures.[4,5,6] To improve the environmental footprint of the preparation of these materials and the devices in which they are applied, nanocatalysis is a very valuable tool. We prepared novel Pd/Pt bimetallic nanoparticles stabilized by a bisphosphonic ligand. The nanoparticles were evaluated in classical Suzuki and Sonogashira coupling reactions. They showed a high catalytic activity and could be used in green conditions: low catalyst loading, green solvent, and short reaction time under microwave activation. These new nanocatalysts were then applied to the preparation of pi-conjugated materials by the Suzuki coupling of a dibenzofuran or dibenzothiophene core with triarylamine moieties (Figure 1). These pi-conjugated materials were studied as efficient hole transporting materials (HTM = materials that can extract the positive charge that appears after a photon absorption) in perovskite solar cells (Figure 2).[7]