Utilization of Nonradiative Excited-State Dissipation for Promoted Phototheranostics Based on an AIE-Active Type I ROS Generator.

As for effective multimodal phototheranostic AIEgens, it is important to find strategies for manipulating photophysical dissipation to achieve optimized performance. Herein, a "all-in-one" phototheranostic AIEgen, ( E )-3-(2-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)vinyl)naphtho[1,2- d ]thiazol-1-ium-1-yl)propane-1-sulfonate (NS-STPA) was constructed by a rigid coplanar grafting flexible rotor. NS-STPA nanoparticles (NPs) exhibited NIR fluorescent luminescence (FL) with φ FL 2.78%. Upon 660 nm irradiation, the high photothermal conversion efficiency (39.01%) and effective reactive oxygen species (ROS) generation (5.28 times to Ce6) indicated the nonradiative decays are valuable in phototherapy. High • OH outputs showed NS-STPA NPs were outstanding type I ROS generators. The twisted D-A structure induced a large spin-orbit coupling (SOC), and insertion of thiophene decreased the S 1 -T 1 energy gap (Δ E ST ). The nanoaggregate prolonged the triplet-state lifetime (τ T ). These all facilitate the intersystem crossing (ISC) for NS-STPA NPs. The photoinduced electron transfer resulted in • O 2 - and then • OH generation. In vivo evaluation indicated the promising application of NS-STPA NPs in FL and photothermal dual imaging-guided synergistic photodynamic and photothermal therapies.