The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202105485.Human behavior (e.g., the response to any incoming information) has very complex forms and is based on the response to consecutive external stimuli entering varied sensory receptors. Sensory adaptation is an elementary form of the sensory nervous system known to filter out irrelevant information for efficient information transfer from consecutive stimuli. As bioinspired neuromorphic electronic system is developed, the functionality of organs shall be emulated at a higher level than the cell. Because it is important for electronic devices to possess sensory adaptation in spiking neural networks, the authors demonstrate a dynamic, real-time, photoadaptation process to optical irradiation when repeated light stimuli are presented to the artificial photoreceptor. The filtered electrical signal generated by the light and the adapting signal produces a specific range of postsynaptic states through the neurotransistor, demonstrating changes in the response according to the environment, as normally perceived by the human brain. This successfully demonstrates plausible biological sensory adaptation. Further, the ability of this circuit design to accommodate changes in the intensity of bright or dark light by adjusting the sensitivity of the artificial photoreceptor is demonstrated. Thus, the proposed artificial photoreceptor circuits have the potential to advance neuromorphic device technology by providing sensory adaptation capabilities.

There is a growing demand for human-eye-invisible short-wave infrared (SWIR) detection due to its potential in applications in areas such as medical diagnostics, environmental monitoring, and night vision. PbS colloidal quantum dots (QDs) are a promising light absorber for SWIR detection. Herein, we report on a PbS QD/InGaZnO (IGZO) heterostructure-based phototransistor and flat-panel imager for human-eye-safe SWIR photodetection and high-resolution imaging. Such hybrid phototransistors show good electrical performance and obvious photoresponse behaviors with a maximum responsivity of 104 A/W and specific detectivity of 1012 Jones under 1310 nm SWIR illumination. We found that PbS QD ligand molecules significantly impact the environmental stability. Phototransistors featuring a tetrabutylammonium iodide (TBAI) ligand exhibit excellent air stability with no serious degradation after exposure to air for 3 weeks, while phototransistors with ethanedithiol (EDT) ligands lose their SWIR detecting capability within 2 weeks. Such an improved air stability may be correlated with the TBAI ligand passivation effect that is confirmed by X-ray photoemission spectroscopy analyses. PbS QDs are patterned on the flexible IGZO transistor array by photolithographic lift-off method for implementing a more practical imaging pixel array. Furthermore, we demonstrate a prototype of 1.3 μm SWIR flat-panel image sensor array, establishing its potential application in advanced developments as a gate-tunable, highly sensitive, high-resolution, and large area flat-panel SWIR imager.

We report the effect of oxidation on PbS quantum dot (QD) photodetectors using rapid thermal annealing (RTA) and furnace annealing in air at different durations and temperatures. Air-annealed QD films using RTA had an improved specific detectivity of up to 1.51 × 10 12 Jones with a responsivity of up to 1.895 × 10 3 A/W at 1 kHz. We used transient photocurrent decay measurements, Xray photoelectron spectroscopy, and frequency response measurements to investigate the origin of this effect. We found that short-term annealing with RTA in air increases the product of carrier mobility and carrier lifetime (μτ) of the QD photoconductors, which leads to high photoconductive gain and bandwidth.

In article number 2105485, Tae-Yeon Seong and co-workers experimentally demonstrate dynamic photoadaptation behavior of an integrated optoelectronic device array that mimics the functionality of the biological visual nervous system. The device array, which is designed to adapt to repeated optical stimuli that change according to external conditions, exhibits excellent performance. This autonomic response to stimuli is essential to the improvement of nextgeneration bionic electronics.