The visual system, one of the most crucial units of the human perception system, combines the functions of multi-wavelength signal detection and data processing. Herein, the large-scale artificial synaptic device arrays based on the organic molecule-nanowire heterojunctions with tunable photoconductivity are proposed and demonstrated. The organic thin films of p-type 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene (C8-BTBT) or n-type phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) are used to wrap the InGaAs nanowire parallel arrays to configure two different type-I heterojunctions, respectively. Due to the difference in carrier injection, persistent negative photoconductivity (NPC) or positive photoconductivity (PPC) are achieved in these heterojunctions. The irradiation with different wavelengths (solar-blind to visible ranges) can stimulate the heterojunction devices, effectively mimicking the synaptic behaviors with two different photoconductivities. The long-term and multi-state light memory are also realized through synergistic photoelectric modulation. Notably, the arrays with different photoconductivities are adopted to build the hardware kernel for the visual system. Due to the tunable photoconductivity and response to multiple wavelengths, the recognition rate of neural networks can reach 100% with lower complexity and power consumption. Evidently, these photosynaptic devices are illustrated with retina-like behaviors and capabilities for large-area integration, which reveals their promising potential for artificial visual systems.

中文翻译：

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基于有机分子-纳米线异质结的可调光电导人工视觉系统

视觉系统是人类感知系统最重要的单元之一，集多波长信号检测和数据处理功能于一体。在此，提出并论证了基于具有可调光电导性的有机分子-纳米线异质结的大规模人工突触装置阵列。p型2,7-二辛基[1]苯并噻吩并[3,2-b][1]苯并噻吩(C8-BTBT)或n型苯基-C ₆₁ -丁酸甲酯(PC ₆₁BM)用于包裹InGaAs纳米线并联阵列，分别配置两个不同的I型异质结。由于载流子注入的差异，在这些异质结中实现了持久负光电导（NPC）或正光电导（PPC）。不同波长（可见光范围内的日盲）的照射可以刺激异质结器件，有效地模拟具有两种不同光电导的突触行为。长期和多状态的光记忆也通过协同光电调制实现。值得注意的是，采用具有不同光导率的阵列来构建视觉系统的硬件内核。由于可调的光电导性和对多个波长的响应，神经网络的识别率可以达到100%，复杂度和功耗更低。显然，这些光突装置具有类似视网膜的行为和大面积集成能力，这揭示了它们在人工视觉系统方面的巨大潜力。