synaptic functions is fundamental to the realization of brain-like computing.Recently, many research advances have been made in the field of artificial synapses, [4] such as memristors, [5] phasechange memory, [6] and field-effect transistors [7] have been exploited to simulate synaptic behaviors. Notably, interest has arisen in organic synaptic transistors, [8] which can combine the advantages of organic electronics, such as low cost, flexibility, and ease of solution fabrication, together with the benefit of multi-terminal synaptic devices for more controllable test parameters. [9] Compared to conventional planar transistors, vertical organic field-effect transistors (VOFETs) are structurally different. [10] Attributing to their adjustable channel lengths determined by the thickness of active layers, they can be simply controlled to sub-micron level or nanometer level in channel length. Small channel length implies high on-state conductance and low voltage operation for the device. [11] The characteristics of VOFETs are consistent with requirements for low voltage operation and low energy consumption of artificial synaptic devices. Furthermore, VOFETs have some potentially unique advantages. Large-scale integration of devices can be achieved through crossbar stacking owing to the vertical electrode placement. The vertical current flow in VOFET could be more tolerant of channel cracks caused by device bending or stretching, [12] which provides a promising approach for the next generation of flexible microelectronic devices.Here, we have fabricated photonic synaptic devices with the structure of VOFETs for the first time. In our work, vertical structure transistors have been designed and constructed, in which networks of single-walled carbon nanotubes (SWCNTs) served as the bottom electrode, CsPbBr 3 quantum dots (QDs) were selected as light-harvesting material, a p-type organic polymer semiconductor, poly[2,5-bis(2-octyldodecyl)pyrrolo [3,4c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2″;5‴,2‴quaterthiophen-5,5‴-diyl)] (PDPP4T), was used as the channel material. PEDOT: PSS (conductive polymer) acted as the top transparent electrode, which could transmit light signals for synaptic activities owing to its transparency. In this photonic synaptic device, typical functions of biological synapses, such as excitatory post-synaptic current (EPSC), short-term plasticity (STP), and long-term plasticity (LTP), have been successfully Artificial synapses have shown great potential in the research of artificial intelligence and brain-like computing. Artificial synaptic devices based on vertical organic field-effect transistors (VOFETs) exhibit shorter carrier transmission distances and more stable source-drain currents than conventional planar organic transistors due to their smaller channel lengths. By taking advantage of the vertical structure, low working voltage can be achieved. Here, vertical synaptic devices with working voltage as low as 10 µV and ultra-low power consumption (≈1.3 fJ per spike) are proposed....

Characterizations and Measurements: For electrical measurement, Keithley 4200 semiconductor characterization system was used to measure the output curve, transfer curve, and other synaptic performances. UV-vis absorption spectrum of chlorophyll-a was carried out by UV-vis spectrometer (Agilent Cary 5000). The surface morphology of pure SWCNTs was observed by SEM. AFM was performed to present the distribution of these nanotubes as well.

Artificial visual systems with image sensing and storage functions have considerable potential in the field of artificial intelligence. Light‐stimulated synaptic devices can be applied for neuromorphic computing to build artificial visual systems. Here, optoelectronic synaptic transistors based on 5,15‐(2‐hydroxyphenyl)‐10,20‐(4‐nitrophenyl)porphyrin (TPP) and dinaphtho[2,3‐b:2′,3′‐f ]thieno[3,2‐b]thiophene (DNTT) are demonstrated. By utilizing stable TPP with high light absorption, the number of photogenerated carriers in the transport layer can be increased significantly. The devices exhibit high photosensitivity and tunable synaptic plasticity. The synaptic weight can be effectively modulated by the intensity, width, and wavelength of the light signals. Due to the high light absorption of TPP, an ultrasensitive artificial visual array based on these devices is developed, which can detect weak light signals as low as 1 µW cm−2. Low‐voltage operation is further demonstrated. Even with applied voltages as low as −70 µV, the devices can still show obvious responses, leading to an ultralow energy consumption of 1.4 fJ. The devices successfully demonstrate image sensing and storage functions, which can accurately identify visual information. In addition, the devices can preprocess information and achieve noise reduction. The excellent synaptic behavior of the TPP‐based electronics suggests their good potential in the development of new intelligent visual systems.

Ionically conductive metal-organic framework-based sensors combining the features of high stability, fast response speed, excellent reversibility, and high sensitivity to trace amounts of LIB electrolyte leakage were developed. The sensors were able to signal a leak while the voltage of the leaking battery was kept at almost the same level as that of a pristine battery, which showed the capability of hours of early warning from the sensors. This excellent performance made the sensors good candidates for safety assurance in a wide range of LIB applications.

The investigation of transistor-based artificial synapses in bioinspired information processing is undergoing a booming exploration, which is the stable building block for brain-like computing. Given that the storage and computing...