Tailored Energy Funneling in Photocatalytic π-Conjugated Polymer Nanofibers for High-Performance Hydrogen Production.

Abstract

The creation of artificial high-performance photosynthetic assemblies with a tailorable antenna system to deliver absorbed solar energy to a photosynthetic reaction center, thereby mimicking biological photosynthesis, remains a major challenge. We report the construction of recyclable, high-performance photosynthetic nanofibers with a crystalline π-conjugated polyfluorene core as an antenna system that funnels absorbed solar energy to spatially defined sensitized Co(II) porphyrin photocatalysts for the hydrogen evolution reaction. Highly effective energy funneling was achieved by tuning the dimensions of the nanofibers to exploit the very long exciton diffusion lengths (>200 nm) associated with the highly crystalline polyfluorene core formed using the living crystallization-driven self-assembly seeded growth method. This enabled efficient solar light-driven hydrogen production from water with a turnover number of over 450 for 8 h of irradiation, an H2 production rate of ca. 65 mmol h-1 g-1, and an overall quantum yield of 0.4% in the wavelength region (<405 nm) beyond the absorption of the molecular photocatalyst. The strategy of using a tailored antenna system based on π-conjugated polymers and maximizing exciton transport to a reaction center reported in this work opens up future opportunities for potential applications in other fields such as solar overall water splitting, CO2 reduction, and photocatalytic small molecule synthesis.