Boosting internal electric field by breaking cell symmetry in polymeric photocatalysts for visible-light-driven sterilization.

The inefficient charge separation and transfer (CST) process has been a major obstacle that limits the catalytic activity of polymeric photocatalysts. Here we propose a symmetry-breaking strategy to regulate the internal electric field (IEF) in crystalline polymers for enhanced CST and photocatalytic efficiency. As a proof of concept, two crystalline linear copolymers, p-phenylenediamine/m-phthalaldehyde (PDA-MAH) and p-phenylenediamine/p-phthalaldehyde (PDA-PAH), were synthesized. By eliminating the center of symmetry in unit cell, we observed robust IEF in the non-centrosymmetric PDA-MAH, as compared to the centrosymmetric PDA-PAH. Such strong IEF was extended throughout the catalyst bulk to accelerate the CST process in PDA-MAH, resulting in a photocatalytic sterilization performance under visible light irradiation that surpassed the best of the previously reported polymeric photocatalysts. This work presents a promising paradigm for tailoring polymeric semiconductors with efficient CST process.