Multichannel Through-Space Charge Transfer Triplet Photosensitizers for Rapid Visible-Light Polymerization and...

Visible-light-driven polymerization offers unparalleled spatiotemporal control and energy efficiency, yet its practical performance is fundamentally constrained by the excited-state dynamics of the photosensitizer. In this study, we report a class of ortho-positioned multi-donor-acceptor molecules featuring multichannel through-space charge transfer (TSCT) characteristics as highly efficient, heavy-atom-free triplet photosensitizers. By constructing a highly twisted three-dimensional (3D) charge-transfer network, these molecules achieve exceptional photophysical performance, including high intersystem crossing (ISC) quantum yields (Φ_ISC up to 0.86), microsecond-scale triplet lifetimes, and an extraordinarily small singlet-triplet energy gap (ΔE_ST as low as 0.008 eV), while maintaining high triplet energies and strong visible-light absorption. Benefiting from these attributes, the TSCT photosensitizers efficiently activate diphenyl ketone benzoyl oxime ester coinitiators via a triplet-triplet energy transfer (TTEnT) mechanism, enabling rapid and well-controlled acrylate polymerization under low-intensity visible-light irradiation. Importantly, this strategy enables, for the first time, the application of multichannel TSCT photosensitizers in digital light processing (DLP) 3D printing, allowing high-resolution fabrication of complex 3D architectures under ambient conditions with excellent operational robustness and biocompatibility. This work establishes a versatile molecular platform for the rational design of organic triplet photosensitizers and advances visible-light-based precision manufacturing technologies.