Elemental-Doping-Induced Orbital Redistribution in Conjugated Polymer Boosts Charge-Transfer-Mediated Singlet Oxygen Production.

Abstract

Beyond the traditional exciton-based energy transfer, carrier-involved charge transfer provides an alternative pathway to overcoming spin restriction in photocatalytic singlet oxygen (1O2) generation. However, the charge-transfer-mediated method usually suffers from insufficient charge-carrier concentration and distribution, which are related to the electronic band structure. Herein, exemplified by polymeric carbon nitride (PCN), we propose an orbital-redistribution strategy for facilitating charge-transfer-mediated 1O2 generation. On the basis of theoretical simulation and spectroscopic characterizations, we demonstrated that the incorporation of bromine could dramatically facilitate the redistribution of the HOMO and LUMO in PCN, resulting in promoted exciton dissociation and adjacent electron/hole distribution. Benefiting from those, bromine-doped polymeric carbon nitride (Br-PCN) exhibited an obvious enhancement in the production of 1O2 via a two-step charge-transfer process. This work not only uncovers a promising method for regulating photoexcitation in polymeric photocatalysts but also sheds new light on photocatalytic 1O2 generation.