Key Laboratory for UV Light-Emitting Materials and Technology, Ministry of Education , Northeast Normal University , 5268 Renmin Street , Changchun 130024 , China.
ACS Appl Mater Interfaces. 2018 Jun 27;10(25):21755-21763. doi: 10.1021/acsami.8b07850. Epub 2018 Jun 13.
Hybrid organic-inorganic perovskite, well-known as light-absorbing materials in solar cells, have recently attracted considerable interest for applications in resistive switching (RS) memory. A better understanding of the role of interface state in hybrid perovskite materials on RS behavior is essential for the development of practical devices. Here, we study the influence of interface state on the RS behavior of an Au/CHNHPbI/FTO memory device using a simple air exposure method. We observe a transition of RS hysteresis behavior with exposure time. Initially no hysteresis is apparent, but air exposure induces bipolar RS and a negative differential resistance (NDR) phenomenon. The reductions of I/Pb atomic ratio and work function on the film surface are examined using XPS spectra and Kelvin probe technique, verifying the produce of donor-type interface states (e.g., iodine vacancies) during CHNHPbI film degradation. Studies on complex impedance spectroscopy confirm the responsibility of interface states in NDR behavior. Eventually, the trapping/detrapping of electrons in bulk defects and at interface states accounts for the bipolar RS behavior accompanied with the NDR effect.
杂化有机-无机钙钛矿作为太阳能电池中的光吸收材料，最近因其在电阻式开关（RS）存储器中的应用而引起了相当大的关注。更好地理解界面态在杂化钙钛矿材料中的 RS 行为中的作用对于实际器件的开发至关重要。在这里，我们使用简单的空气暴露方法研究了界面态对 Au/CHNHPbI/FTO 存储器器件 RS 行为的影响。我们观察到随着暴露时间的变化，RS 迟滞行为发生了转变。最初没有明显的迟滞，但空气暴露会诱导双极 RS 和负微分电阻（NDR）现象。使用 XPS 光谱和 Kelvin 探针技术研究了薄膜表面的 I/Pb 原子比和功函数的降低，证实了在 CHNHPbI 薄膜降解过程中产生了施主型界面态（例如碘空位）。复阻抗谱研究证实了界面态在 NDR 行为中的作用。最终，体缺陷和界面态中的电子俘获/释放解释了伴随着 NDR 效应的双极 RS 行为。
