Improved Singlet Oxygen Production by Synergistic Effect via a Dual-Core Photosensitizer Doped Polymer Fibrous Films: Synthesis and Performance

Singlet oxygen ((1)O(2)) is a common reactive oxygen species that has found wide application in wastewater processing, photochemical synthesis, and photodynamic therapy. In this paper, a dual-core metal [a Re(I)-based component and a Gd(III)-based component] photosensitizer was synthesized and doped into polymer fibrous films for (1)O(2) generation. Here the Re(I)-based component is responsible for the photosensitizing reaction which directly transformed (3)O(2) to (1)O(2), while the Gd(III)-based component served as an auxiliary part that assisted the transformation from (3)O(2) to (1)O(2) via synergistic effect by its triplet excited ligands. The photophysical parameters of this photosensitizer (denoted as Re-Gd) and its fibrous films (denoted as Re-Gd@PVP) were carefully recorded, discussed, and compared. It was found that the excited state lifetime and photostability of Re-Gd were both improved after being doped into fibrous films, favoring (1)O(2) generation. The (1)O(2) generation performance comparison between Re-Gd in the solid state, in solution, and fibrous films suggested that (1)O(2) generation performance was indeed improved by the electrospinning films. In addition, the positive factor of synergistic effect on improving (1)O(2)-producing efficiency was confirmed by comparing Re-Gd@PVP films with reference films with a single-core metal photosensitizer having no synergistic effect.