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Optoelectronic synaptic devices have been regarded as the key component in constructing neuromorphic computing systems. However, the optoelectronic synapses based on conventional 2D transistor are still suffering low photosensitivity and volatile retention behavior, which can affect the recognition accuracy and long-term memory. Here, a novel optoelectronic synaptic device based on surface-state-rich CdSe nanobelt photosensitized 2D MoS2 transistor is demonstrated. Benefiting from the excellent light absorption of CdSe and effective charge trapping at the hetero-interface, the device exhibits not only high photosensitivity but also long retention time (>1,500 s). In addition, typical synaptic functions including the excitatory postsynaptic current, paired-pulse facilitation, the transformation from short-term to long-term plasticity, the transformation from short-term to long-term plasticity, spike-amplitude-dependent plasticity, and learning-forgetting-relearning process are successfully simulated and modulated by light stimulation. Most importantly, an artificial neural network is simulated based on the optical potentiation and electrical habituation characteristics of the synaptic devices, with recognition accuracy rates of 89.2, 93.8, and 91.9 % for file type datasets, small digits, and large digits are achieved. This study demonstrates a simple and efficient way to fabricate highly photosensitive optoelectronic synapse for artificial neural networks by combining the merits of specific materials and device architecture.

The vertical electronic and optoelectronic devices based on 2D materials have shown great advantages over lateral devices, such as higher current density, faster switch speed, and superior short-channel control. However, it is difficult to fabricate vertical device with conventional metal deposition methods due to the aggressive process usually results in damage to the contact region. Here, we develop a simple and effective metal transfer technique and fabricate p-type and n-type WSe2 transistors by using metals with different work functions and subsequently create a vertical WSe2 transistors with a 18-nm-thick channel, which retain good gate coupling effect. Furthermore, a vertical WSe2 photodiode is constructed with graphene and Pt as asymmetric van der Waals (vdW) contacts. The work-function difference between graphene and Pt generates a built-in electric filed, leading to a high current rectification over 105. Under 405 nm laser illumination, the device exhibits excellent self-powered photodetection properties, including a high responsivity of 0.28 A W−1, fast response speed of 24 μs, and large light on/off ratio exceeding 105 at zero bias, which surpass most of the vdW photodiodes. This work demonstrates that the metal transfer technique is a promising strategy for the construction of high-performance vertical optoelectronic devices.

The synthesis of high‐entropy alloys (HEAs) with ultra‐small particle sizes has long been a challenging task. The complex and time‐consuming synthesis process hinders their practical application and widespread adoption. This study presents the novel synthesis of TiO2 nanoparticles loaded with a quinary high‐entropy alloy through flame spray pyrolysis (FSP) for the first time. The extremely fast heating rate of flame combustion makes the precursor fast pyrolysis gasification, high temperature in the flame field promotes the metal vapor mixing uniformly, and the fast quenching process can reduce the particle aggregation sintering, the ultra‐small particle size of HEA firmly attached to the TiO2 surface. The catalysts prepared via this gas‐to‐particle pathway exhibit excellent performance in CO2 hydrogenation, achieving a conversion rate of 62% at 450 °C, and maintaining their activity for over 220 h without significant particle agglomeration. This finding provides valuable insights for the future design of catalytically active materials with enhanced activity and long‐term stability. [ABSTRACT FROM AUTHOR]

Optoelectronic synaptic devices have been regarded as the key component in constructing neuromorphic computing systems. However, the optoelectronic synapses based on conventional 2D transistor are still suffering low photosensitivity and volatile retention behavior, which can affect the recognition accuracy and long-term memory. Here, a novel optoelectronic synaptic device based on surface-state-rich CdSe nanobelt photosensitized 2D MoS2 transistor is demonstrated. Benefiting from the excellent light absorption of CdSe and effective charge trapping at the hetero-interface, the device exhibits not only high photosensitivity but also long retention time (>1,500 s). In addition, typical synaptic functions including the excitatory postsynaptic current, paired-pulse facilitation, the transformation from short-term to long-term plasticity, the transformation from short-term to long-term plasticity, spike-amplitude-dependent plasticity, and learning-forgetting-relearning process are successfully simulated and modulated by light stimulation. Most importantly, an artificial neural network is simulated based on the optical potentiation and electrical habituation characteristics of the synaptic devices, with recognition accuracy rates of 89.2, 93.8, and 91.9 % for file type datasets, small digits, and large digits are achieved. This study demonstrates a simple and efficient way to fabricate highly photosensitive optoelectronic synapse for artificial neural networks by combining the merits of specific materials and device architecture. [ABSTRACT FROM AUTHOR]