Structure Engineered High Piezo‐Photoelectronic Performance for Boosted Sono‐Photodynamic Therapy

Abstract

Sono-photodynamic therapy is hindered by the limited tissue penetration depth of the external light source and the quick recombination of electron-hole owing to the random movement of charge carriers. In this study, orthorhombic ZnSnO₃ quantum dots (QDs) with piezo-photoelectronic effects are successfully encapsulated in hexagonal upconversion nanoparticles (UCNPs) using a one-pot thermal decomposition method to form an all-in-one watermelon-like structured sono-photosensitizer (ZnSnO₃ @UCNPs). The excited near-infrared light has high penetration depth, and the watermelon-like structure allows for full contact between the UCNPs and ZnSnO₃ QDs, achieving ultrahigh Förster resonance energy transfer efficiency of up to 80.30%. Upon ultrasonic and near-infrared laser co-activation, the high temperature and pressure generated lead to the deformation of the UCNPs, thereby driving the deformation of all ZnSnO₃ QDs inside the UCNPs, forming many small internal electric fields similar to isotropic electric domains. This piezoelectric effect not only increases the internal electric field intensity of the entire material but also prevents random movement and rapid recombination of charge carriers, thereby achieving satisfactory piezocatalytic performance. By combining the photodynamic effect arising from the energy transfer from UCNPs to ZnSnO₃ , synergistic efficacy is realized. This study proposes a novel strategy for designing highly efficient sono-photosensitizers through structural design.