Wang Cheng, Chen Yu, Zhang Bin, Liu Shanshan, Chen Qibin, Cao Yaming, Sun Sai
Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Dalton Trans. 2016 Jan 14;45(2):484-8. doi: 10.1039/c5dt03969j.
A solution-processed organometallic halide perovskite-based bulk heterojunction (BHJ) memory device with a configuration of indium-doped tin oxide (ITO)/CH3NH3PbI3:PVK/Al has been successfully fabricated. Under a threshold voltage of -1.57 V, this device shows a nonvolatile write-once read-many-times (WORM) memory effect, with a maximum ON/OFF current ratio exceeding 10(3). In contrast, the ITO/CH3NH3PbI3/Al device showed only conductor characteristics, while the PVK-based device exhibited insulator behavior. Upon being subjected to voltages, an interesting filamentary nature of the CH3NH3PbI3:PVK film was also observed in situ at the microscopic nanometer level using a conductive atomic force microscopy (C-AFM) technique with a device configuration of Si/Pt/CH3NH3PbI3:PVK/Pt. The mechanism associated with the memory effect is discussed. The electric-field-induced intermolecular charge transfer effect between CH3NH3PbI3 and PVK, and the possible conformational ordering of the PVK side-chains/backbone under an applied bias voltage, may cause the electrical conductivity switching and WORM effect in the reported BHJ device.
一种具有氧化铟锡（ITO）/CH3NH3PbI3:PVK/Al结构的溶液处理有机金属卤化物钙钛矿基体异质结（BHJ）存储器件已成功制备。在-1.57 V的阈值电压下，该器件呈现出非易失性一次写入多次读取（WORM）存储效应，最大开/关电流比超过10(3)。相比之下，ITO/CH3NH3PbI3/Al器件仅表现出导体特性，而基于PVK的器件则表现出绝缘体行为。在施加电压时，使用具有Si/Pt/CH3NH3PbI3:PVK/Pt器件结构的导电原子力显微镜（C-AFM）技术，还在微观纳米尺度原位观察到了CH3NH3PbI3:PVK薄膜有趣的丝状性质。讨论了与存储效应相关的机制。CH3NH3PbI3和PVK之间的电场诱导分子间电荷转移效应，以及在施加偏置电压下PVK侧链/主链可能的构象有序化，可能导致所报道的BHJ器件中的电导率切换和WORM效应。
