p-n Heterojunction-based Thermoelectric Generator for Highly Efficient Cancer Thermoelectric Therapy

Photothermal therapy (PTT) based on the light-heat conversion principle has attracted extensive attention in preclinical research, however, the hyperthermia resulted the treatment-related damage to surrounding tissues prevents further advanced clinical practice. Here, we developed a thermoelectric therapy (TET) based on p-n heterojunction (SrTiO3/Cu2Se nanoplates) on the principle of light-heat-electricity-chemical energy conversion, demonstrating great potential for cancer treatment. The principle of TET is based on light-heat-electricity-chemical energy conversion, regarded as an upgraded version of PTT. Upon laser irradiation and subsequently natural cooling-induced the mild temperature gradient (35-45 oC), a self-build-in electric field was constructed and thereby facilated electrons and holes separation in bulk SrTiO3 and Cu2Se. Importantly, the contact between SrTiO3 (n type) and Cu2Se (p type) constructed another interficial electric field, which further guided the seperated electrons and holes to transfer to re-locate onto the surfaces of SrTiO3 and Cu2Se, respectively. The formation of two electric fields in bulk and interface of SrTiO3/Cu2Se nanoplates minimized probability of charges recombination. Of note, high-performance superoxide radicals (·O2−) and hydroxyl radicals (·OH) generation from O2 and H2O under catalization by seperated electrons and holes, led to intracellular ROS burst and cancer cells apoptosis without apparent damage to surrounding tissues. As far as it is known, this is the first report on TET based a p-n heterojunction in biomedical field. Construction of bulk and interficial electric fields in heterojunction for improving charges separation and transfer is also expected to provide a robust and universal strategy for diverse applications including energy, environment, and biomedical engineering.