Mimicking biological synapses with resistive random switching memory (RRAM) can lay a concrete foundation for the future of artificial intelligence. RRAMs based on low-cost and solution-processed organic materials provide a competitive approach. Here, we report an artificial synaptic device with a solution-processed small molecule (bis-4-(N-carbazolyl)phenyl)phenylphosphine oxide (BCPO) based RRAM. The BCPO-based RRAM exhibits reproducible resistive switching behavior, a long retention time as well as good thermal tolerance with a sufficient on/off current ratio. In situ Kelvin probe force microscopy (KPFM), conductive atomic force microscopy (C-AFM) and density function theory (DFT) calculations demonstrate that both the redox state and the trap-filled space charge limited current (SCLC) determine the resistive switching of a BCPO-based RRAM. Furthermore, the fabricated device was employed to emulate a biological synapse in which several synaptic functions, including spike-rate-dependent plasticity (SRDP), a transition from short-term plasticity (STP) to long-term plasticity (LTP) and spike-time-dependent plasticity (STDP), were realized. To the best of our knowledge, this is the first successful demonstration of solution-processed small molecules in artificial synaptic devices. The BCPO layer is solution-processed at low temperature which is compatible with a flexible substrate and printable electronics. We believe this electronic synapse will have a wide range of applications in future neuromorphic computing.

中文翻译：

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使用溶液可加工的有机小分子进行生物启发的电子突触†

用电阻随机开关存储器（RRAM）模仿生物突触可以为人工智能的未来奠定坚实的基础。基于低成本和溶液处理的有机材料的RRAM提供了一种有竞争力的方法。在这里，我们报告与基于溶液处理的小分子（双-4-（N-咔唑基）苯基）苯基膦氧化物（BCPO）的RRAM的人工突触设备。基于BCPO的RRAM具有可再现的电阻开关性能，较长的保留时间以及良好的耐热性以及足够的开/关电流比。原位开尔文探针力显微镜（KPFM），导电原子力显微镜（C-AFM）和密度函数理论（DFT）计算表明，氧化还原状态和陷阱填充的空间电荷限制电流（SCLC）都决定了BCPO的电阻切换基于RRAM。此外，制造的装置可用来模拟生物突触，其中一些突触功能包括尖峰速率依赖性可塑性（SRDP），从短期可塑性（STP）到长期可塑性（LTP）的转变以及尖峰-实现了与时间有关的可塑性（STDP）。据我们所知，这是在人工突触设备中溶液处理的小分子的首次成功演示。BCPO层在低温下进行固溶处理，与柔性基板和可印刷电子设备兼容。