A pH stable fluoran-triphenylamine photosensitizer with efficient type I and type II ROS generation.

Photosensitizers (PSs) with robust pH stability and the ability to generate both type I and type II reactive oxygen species (ROS) have gained significant attention due to their versatility in various applications. In this study, we employed an electron donor-acceptor engineering strategy to design and synthesize a fluoran-triphenylamine photosensitizer (Fl-TPA), using an ester-protected ring-opened fluoran cation as the electron acceptor and triphenylamine (TPA) as the electron donor. Compared to fluoran with a spirolactone structure, Fl-TPA exhibits a significant redshift in absorption, with good light capture capabilities in the 300-600 nm range.