Zeng Fanju, Guo Yuanyang, Hu Wei, Tan Yongqian, Zhang Xiaomei, Feng Julin, Tang Xiaosheng
Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
School of Big Data Engineering, Kaili University, Kaili, Guizhou 556011, China.
ACS Appl Mater Interfaces. 2020 May 20;12(20):23094-23101. doi: 10.1021/acsami.0c03106. Epub 2020 May 6.
Recently, several types of lead halide perovskites have been demonstrated as active layers in resistive switching memory or artificial synaptic devices for neuromorphic computing applications. However, the thermal instability and toxicity of lead halide perovskites severely restricted their further practical applications. Herein, the environmentally friendly and uniform CsCuI perovskite films are introduced to act as the active layer in the Ag/CsCuI/ITO memristor. Generally, the Ag ions could react with iodide ions and form AgI compounds easily, so the Ag/PMMA/CsCuI/ITO memristor was designed by employing the ultrathin polymethylmethacrylate (PMMA) layer to avoid the direct contact between the top Ag electrode and CsCuI perovskite films. After optimization, the obtained memristor demonstrated bipolar resistive switching with low operating voltage (< ±1 V), large on/off ratio (10), stable endurance (100 cycles), and long retention (>10 s). Additionally, biological synaptic behaviors including long-term potentiation and long-term depression have been investigated. By using the MNIST handwritten recognition data set, the handwritten recognition rate based on experimental data could reach 94%. In conclusion, our work provides the opportunity of exploring the novel application for the development of next-generation neuromorphic computing based on lead-free halide perovskites.
最近，几种类型的卤化铅钙钛矿已被证明可作为用于神经形态计算应用的电阻式开关存储器或人工突触器件的活性层。然而，卤化铅钙钛矿的热不稳定性和毒性严重限制了它们的进一步实际应用。在此，引入了环境友好且均匀的CsCuI钙钛矿薄膜，以用作Ag/CsCuI/ITO忆阻器的活性层。通常，Ag离子容易与碘离子反应并形成AgI化合物，因此通过采用超薄聚甲基丙烯酸甲酯（PMMA）层来设计Ag/PMMA/CsCuI/ITO忆阻器，以避免顶部Ag电极与CsCuI钙钛矿薄膜直接接触。经过优化后，所获得的忆阻器表现出双极电阻开关特性，具有低工作电压（<±1 V）、大的开/关比（10）、稳定的耐久性（100个循环）和长保持时间（>10 s）。此外，还研究了包括长时程增强和长时程抑制在内的生物突触行为。通过使用MNIST手写识别数据集，基于实验数据的手写识别率可达94%。总之，我们的工作为探索基于无铅卤化物钙钛矿的下一代神经形态计算开发的新应用提供了机会。
