Pyrene-Based Covalent Organic Polymers for Enhanced Photovoltaic Performance and Solar-Driven Hydrogen Production

Photovoltaic solar-driven hydrogen production is promising but challenging. Herein, we report that pyrene-based covalent-organic-polymer-modified (COP-modified) TiO2 leads to composite materials with high power conversion efficiency (PCE). The suitable band position, inherent optimized pore size, large specific surface area, and wide light absorption region of COP-64 are beneficial for the photo-to-electron conversion and electron transfer efficiency. As a result, the PCE of the modified photoanode-assembled dye-sensitized solar cell (DSSC, N719 as the dye) achieved as high as 10.0% with the optimal COP-64 addition of 0.6 wt %, exhibiting a more than 20% promotion compared with the pristine TiO2 (7.9%). Moreover, the as-obtained integrated tandem DSSCs exhibited a high solar-to-hydrogen efficiency of 7.5% for the water splitting, as well as high stability and hydrogen production performance. Therefore, the COP-modified TiO2 photoanode assembled in DSSCs paved a new effective pathway to improve power conversion efficiency for solar-light-assisted water splitting and other solar-light-driven photocatalytic applications.