All-Solution-Processed InGaO/PbI₂ Heterojunction for Self-Powered Omnidirectional Near-Ultraviolet Photodetection and Imaging

The persistent photocurrent (PPC) and high carrier concentration are challenging the ultraviolet photodetection behaviors of amorphous InGaO films. Herein, InGaO/PbI2 heterojunction is constructed by an all-solution synthesis process to set up a built-in electric field at the heterojunction interface, which is aimed at the inhibition of PPC, suppression of dark current, and promotion of photogenerated carrier separation. With an optimized In content of 90%, the as-fabricated InGaO/PbI2 heterojunction photodetector exhibits excellent self-powered near-ultraviolet photodetection behaviors with high Ilight/Idark ratio of 10(4), ultralow dark current of 10(-13 )A and fast response times of 0.8/0.6 ms. Additionally, benefiting to the all-solution synthesis process and amorphous characteristic, InGaO/PbI2 heterojunction can be implanted onto any useful substrates to achieve the specific function of photodetection. The as-fabricated InGaO/PbI2 heterojunction flexible self-powered photodetector exhibits outstanding mechanical flexibility, bending endurance, and photoelectric stability. When the InGaO/PbI2 heterojunction is implanted onto the transparent substrate, it demonstrates excellent omnidirectional self-powdered photodetection performance and imaging capability. All results promise all-solution-processed InGaO for next-generation advanced optoelectronics.