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 Ilight/Idark 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 Ilight/Idark 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.