Deep Ultraviolet Light Stimulated Synaptic Transistors Based on Poly(3-hexylthiophene) Ultrathin Films

Abstract

Deep ultraviolet (DUV)-light-stimulated artificial synaptic devices exhibit potential applications in various disciplines including intelligent military monitoring, biological and medical analysis, flame detection, etc. Along these lines, we report here a DUV-light-stimulated synaptic transistor fabricated on a poly­(3-hexylthiophene) (P3HT) ultrathin film that responds selectively to DUV light. Significantly, our devices have the ability to successfully simulate various synapse-like behaviors including excitatory postsynaptic currents (EPSCs), paired-pulse facilitation (PPF), short-term memory (STM), long-term memory (LTM), STM-to-LTM transition, and learning and forgetting behaviors. Moreover, the proposed artificial synaptic structures were also fabricated on flexible poly­(ethylene terephthalate) (PET) substrates and also successfully simulated typical synaptic behaviors, which could be of great importance for wearable applications.

A brief review on device operations and working mechanisms of organic transistor photomemories

“…60 Knowing these parameters for the photosynaptic transistor-based device is essential. In the latter paragraph, the progress of photosynaptic transistors will be elaborated on the latest reports found in the literature which are not limited to the use of photoactive organics/polymers, 97,130,131 but also hybrid-inorganics and other potential photoactive materials. 115,118,119,121,132…”

“…121 Last but not least, the development of polymer-based photosynaptic transistors keeps pace with other potential materials. 122,130,131,134 In this scope, a photosynaptic transistor utilizing P3HT- b -P2VP block copolymer active layer could emulate PPF, STDP/SRDP, and STP/LTP behaviors. 130 The corresponding LTM can keep the current contrast to 10 5 , the STM with a high PPF ratio of 1.38, and an ultralow energy consumption calculated ca.…”

“…A simpler polymer-based photosynaptic device with capabilities to simulate various synapse-like behaviors such as EPSC, PPF, STM/LTM and its transition using DUV light was demonstrated. 131 The device contains of P3HT as active channel and CYTOP as a modifying layer for the dielectric surface with DEPSC values recorded up to 6.2 nA under the exertion of a single light pulse intensity of 0.15 mW cm À2 and duration of 4 s. And the very recent progress on photosynaptic device that using the same concept of photo-assisted operations (see in subsection of 4.4), while investigating the effect of molecular weight (Mw) of polymer electret to the photosynaptic behavior have been reported. 134 With poly(N-vinylcarbazole) (PVK) as the case study, such device could exhibit a larger memory window (28.2 V) bundling with an instantaneous programming speed of 1 ms for lower Mw PVK electret.…”

Optoelectronic Artificial Synaptic Device Based on Amorphous InAlZnO Films for Learning Simulations

“…We fabricated a single synaptic device based on an a -IAZO monolayer semiconductor operated in a three-terminal TFT mode. The TFT structure can record information through changes in the conductance of the semiconductor channel layer, , with the gate voltage as a window to perceive the external environment and simulate the influence of environmental factors on human learning. As a transparent electrode, , ITO can transmit incident light so that the light impinging on the device is not blocked, making the device more responsive.…”

Multistimuli-Responsive Plasticity Transitions of a Phototransistor Conferred by Using Thermoresponsive Polyfluorene Block Copolymers

“…The rapid technological developments in the era of Internet of Things, sensor networks, robotics, and artificial intelligence bring new challenges to develop material systems and architectures for memory technologies with large storage capacity. − Despite intensive progress in this field, conventional voltage-driven memory lags far behind the increasing demands for high data storage density, fast transmission, and physical miniaturization designs. The state-of-the-art nonvolatile photomemory, which transduce broadband optical stimuli into electrical signals, thereby reducing the dependence on electrical programming, have emerged as a potential candidate in ultrafast, multibit data storage, and noncontact programming memory. − Material systems including inorganic materials, organic–inorganic hybrid composites, conjugated-insulated polymer blends, and block-copolymers (BCPs) have been proposed for nonvolatile photomemory in recent years. − However, the photoresponsivity and memory retention of memory comprising inorganic and composite systems strongly rely on the size control and distribution of trapping units in a nanoscale, which produce cumbersome device fabrication. − …”