Boosting Non-Radiative Decay to Do Useful Work: Development of a Multi-Modality Theranostic System from an AIEgen.

The efficient utilization of energy dissipating from non-radiative excited-state decay of fluorophores was only rarely reported. Herein, we demonstrate how to boost the energy generation of non-radiative decay and use it for cancer theranostics. A novel compound (TFM) was synthesized which possesses a rotor-like twisted structure, strong absorption in the far red/near-infrared region, and it shows aggregation-induced emission (AIE). Molecular dynamics simulations reveal that the TFM aggregate is in an amorphous form consisting of disordered molecules in a loose packing state, which allows efficient intramolecular motions, and consequently elevates energy dissipation from the pathway of thermal deactivation. These intrinsic features enable TFM nanoparticles (NPs) to display a high photothermal conversion efficiency (51.2 %), an excellent photoacoustic (PA) effect, and effective reactive oxygen species (ROS) generation. In vivo evaluation shows that the TFM NPs are excellent candidates for PA imaging-guided phototherapy.