Tailoring of electronic and surface structures boosts exciton-triggering photocatalysis for singlet oxygen generation

Arising from reduced dielectric screening, excitonic effects should be taken into account in ultrathin two-dimensional photocatalysts, and a significant challenge is achieving nontrivial excitonic regulation. However, the effect of structural modification on the regulation of the excitonic aspect is at a comparatively early stage. Herein, we report unusual effects of surface substitutional doping with Pt on electronic and surface characteristics of atomically thin layers of Bi3O4Br, thereby enhancing the propensity to generate O-1(2). Electronically, the introduced Pt impurity states with a lower energy level can trap photoinduced singlet excitons, thus reducing the singlet-triplet energy gap by similar to 48% and effectively facilitating the intersystem crossing process for efficient triplet excitons yield. Superficially, the chemisorption state of O-2 causes the changes in the magnetic moment (i.e., spin state) of O-2 through electronmediated triplet energy transfer, resulting a spontaneous spin-flip process and highly specific O-1(2) generation. These traits exemplify the opportunities that the surface engineering provides a unique strategy for excitonic regulation and will stimulate more research on exciton-triggering photocatalysis for solar energy conversion.

Automated summary

Surface substitutional doping with Pt has significant effects on the electronic and surface characteristics of atomically thin layers of Bi3O4Br, enhancing the generation of O-1(2). The introduced Pt impurity states can trap photoinduced singlet excitons, reducing the singlet-triplet energy gap and facilitating the generation of triplet excitons. Chemisorption state of O-2 causes changes in the magnetic moment of O-2 through electron-mediated triplet energy transfer, resulting in specific O-1(2) generation.