Retinomorphic Motion Detector Fabricated with Organic Infrared Semiconductors

Abstract

Organic retinomorphic sensors offer the advantage of in‐sensor processing to filter out redundant static backgrounds and are well suited for motion detection. To improve this promising structure, here, the key role of interfacial energetics in promoting charge accumulation to raise the inherent photoresponse of the light‐sensitive capacitor is studied. Specifically, incorporating appropriate interfacial layers around the photoactive layer is crucial to extend the carrier lifetime, as confirmed by intensity‐modulated photovoltage spectroscopy. Compared to its photodiode counterpart, the retinomorphic sensor shows better detectivity and response speed due to the additional insulating layer, which reduces the dark current and the RC time constant. Lastly, three retinomorphic sensors are integrated into a line array to demonstrate the detection of movement speed and direction, showing the potential of retinomorphic designs for efficient motion tracking.

Bias Dependence of Organic-Oxide Phototransistors with Peak Infrared Absorption at 1550 nm

“…There are ongoing efforts to develop alternative semiconductors − that facilitate low-cost, monolithic detector fabrication. Among these emerging technologies, organic semiconductors such as donor–acceptor conjugated polymers − enable facile and scalable processing and functionality to infrared wavelengths beyond 1 μm. However, according to the energy-gap law, as the bandgap of organic semiconductors decreases, the recombination rate of photogenerated excitons increases, leading to a decline in device efficiency at longer wavelengths.…”