From insoluble to processable: Aminic solvent dissolution of donor-acceptor conjugated network polymers for fabrication of photocatalytic thin film

Abstract

Conjugated network polymers (CNPs) have gained considerable attention as heterogeneous photocatalysts, however, their limited solubility in solvents poses a significant challenge in employing CNPs for photoreactors. Herein, we report the chemical dissolution of CNPs in aminic solvents to enhance solution processability. The CNPs, synthesized via the Knoevenagel polycondensation, were dissolved into corresponding polymer inks, forming thin films on various substrates through mild heating. Residual functional groups on the CNP surface provided latent reactive sites for liquid amines, facilitating structural disentanglement and dissolution without hindering the pi-conjugation. The resulting polymer films on FTO electrodes exhibited broader light absorbance and > 2-fold enhanced photoresponse compared to CNP powder films. Photocatalytic production of H2O2 using the large-area polymer film (254.4 cm(2)) demonstrated sustained activity with a production rate of 0.21 mM H2O2 h(-1) over 14 h without sacrificial agents. These findings lay the groundwork for applying CNP photocatalysts in chemical, optical, and electronic applications.