UV-to-NIR Harvesting Conjugated Porous Polymer Nanocomposite: Upconversion and Plasmon Expedited Thioether Photooxidation.

Photocatalysts capable of harvesting a broad range of the solar spectrum are essential for sustainable chemical transformations and environmental remediation. Herein, we have integrated NIR-absorbing upconversion nanoparticles (UCNP) with UV-Vis absorbing conjugated porous organic polymer (POP) through the in situ multicomponent C-C coupling to fabricate a UC-POP nanocomposite. The light-harvesting ability of UC-POP is further augmented by loading plasmonic gold nanoparticles (AuNP) into UC-POP. A three-times enhancement in the upconversion luminescence is observed upon the incorporation of AuNP in UC-POP, subsequently boosting the photocatalytic activity of UC-POP-Au. The spectroscopic and photoelectrochemical investigations infer the enhanced photocatalytic oxidation of thioethers, including mustard gas simulant by UC-POP-Au compared to POP and UC-POP due to the facile electron-hole pair generation, suppressed exciton recombination, and efficient charge carrier migration. Thus, the unique design strategy of combining plasmonic and upconversion nanoparticles with a conjugated porous organic polymer opens up new vistas towards artificial light harvesting.