Plasmonic Enhancement of Semiconducting Double Cable Polythiophene-Perylene Diimide Polymer Performance in Artificial Photosynthesis of H2O2

Abstract

Organic semiconducting double cable polymers (DCPs) have emerged as promising single-component donor-acceptor (D-A) photoactive materials. However, their light harvesting and energy conversion efficiencies are limited by their intrinsic chemical nature. Herein, we demonstrate that interfacing DCPs with rationally selected functional additives is an effective avenue to enhance their performance in light driven processes without altering their chemical nature. Capitalizing on the ability of polythiophenes (PTh) to transfer as-prepared plasmonic gold nanoparticles (AuNPs) from aqueous suspensions to organic phase without the need of ligand exchange, a DCP comprising of PTh covalently conjugated to a perylene diimide (PDI) derivative (PTh-PDI-DCP) was employed to produce PTh-PDI-DCP/AuNPs hybrids containing different wt.% of AuNPs. Monitoring changes in the optical and electronic properties of the resulting hybrids as a function of varying wt.% of AuNPs enabled identification of the optimum AuNPs content, which was found to be 13 ±1 wt.% for PTh-PDI-DCP/AuNPs and 10 ±1 wt.% for P3HT/AuNPs prepared for comparison. In photoelectrochemical (PEC) characterizations and application as photocatalyst in artificial photosynthesis of hydrogen peroxide (H2O2), the PTh-PDI-DCP/AuNPs hybrid outperformed all other systems. Comparing the photocatalytic cycles with highest production rates in 10 photocatalytic cycles of artificial photosynthesis of H2O2, PTh-PDI-DCP/AuNPs achieves an H2O2 production rate of 233 ±12 µMmg-1h-1, which corresponds to about 3.8, 2.3 and 1.4-fold enhancements relative to AuNPs, P3HT and P3HT/AuNPs, respectively, and 1.4-fold over PTh-PDI-DCP. In summary, this study provides a viable pathway for expanding the design space of organic photocatalysts via the rational integration of DCPs with complementary functional additives.