Catenated imide-linked porous organic polymers for solar energy harvesting

Abstract

Porous organic polymers (POPs) have attracted significant attention for solar energy applications due to their high surface areas, chemical stability, and tunable structures. However, there is still considerable scope for developing architectural control at the molecular level, improving light-absorption efficiency, and enhancing multifunctional energy-conversion capabilities. Herein, we present a novel catenated imide-linked POP to build interlocked structures with efficient photothermal properties. A catenated imide-linked POP was synthesized via a Co(II)-templated approach, linking perylene tetracarboxylic dianhydride to [Co(2,6-bis(5-aminobenzimidazol-2-yl)pyridine)2]Cl2 (ligand-2), termed Co-abpy-POP. The synergistic contribution of this octahedral Co-complex's properties and the unique interlocked, coupled framework resulted in significant broadband light absorption and high solar energy conversion with multifunctional potential. High-performance in solar energy conversion was demonstrated by (i) interfacial solar steam generation (evaporation rate: 2.22 kg m−2 h−1; solar-to-vapor conversion efficiency: 70%), (ii) photothermoelectric conversion (continuous 0.2 V output in 150 s under 1.0 sun irradiation), and (iii) nanofluid-based direct absorption solar collection (surface temperature increase from 23 °C to 69 °C in 20 minutes). This work highlights the performance of catenated Co-abpy-POP in efficient and stable solar energy conversion heat/electric energy and co-generation of clean water.