Color-Tunable Ambipolar Autonomous Photodetector Based on Heterostructure-Engineered Semiconducting Quantum Dots for Biomimetic Visual Sensing

Self-powered photodetectors with broadband response and color-sensitive ambipolar properties represent a major advancement in optoelectronics. This work presents a robust and fast broadband photodetector with self-powered and color-tunable ambipolar photoconductivity that is achieved using solution-processed MoS2:MoO3 heterostructure quantum dot thin films. The device operates in the absence of external bias due to having an in situ type-II heterojunction between MoS2:MoO3. It exhibits tunable photoresponse with ambipolar behavior if the color of incident light changes like photoreceptors in the retina. The device shows a dark-to-light current ratio of 103, with superlinear light intensity dependence, indicating complex photocarrier dynamics in the presence of defects. Further, it displays a light detection speed efficiently up to 10.65 kHz. With an external quantum efficiency exceeding 60% and a responsivity of 0.25 A/W in the near-infrared region, the combination of self-powering, broadband detection, and color-tunable ambipolar response makes it a promising candidate for next-generation sensing and automation technologies.