Toward Smart, Flexible, and Omnidirectional Self-Powered Photodetection by an All-Solution-Processed In2O3/Pbl2 Heterojunction

Amorphous In₂O₃ film is emerging as a promising oxide semiconductor for next-generation electronics and optoelectronics owing to high mobility and wide band gap. However, the persistent photocurrent phenomenon and high carrier concentration in amorphous In₂O₃ film are challenging the photodetection performances, resulting in a long response time and low I_light/I_dark ratio. In this work, the In₂O₃/PbI₂ heterojunction is constructed by an all-solution synthesis process to inhibit the persistent photocurrent phenomenon and large dark current. Benefiting from the built-in electric field at the heterojunction interface, the In₂O₃/PbI₂ heterojunction photodetector exhibits excellent self-powered photodetection performances with an ultralow dark current of 10^-12 A, a high I_light/I_dark ratio of 10⁴, and fast response times of 0.6/0.6 ms. Furthermore, the entire solution synthesis process and amorphous characteristics enable the fabrication of an In₂O₃/PbI₂ heterojunction photodetector on arbitrary substrates to realize specific functions. When configured onto the polyimide substrate, the In₂O₃/PbI₂ heterojunction photodetector shows excellent mechanical flexibility, bending endurance, and photoresponse stability. When implanted onto the transparent substrate, the In₂O₃/PbI₂ heterojunction photodetector exhibits an outstanding omnidirectional self-powdered photodetection performance and imaging capability. All results pave the way for an all-solution-processed amorphous In₂O₃ film in advanced high-performance photodetectors.