English original title: improved performance of ch3nh3pbi3 – xclx resisitiveswitching memory by assembling 2D / 3D perovskite heterostuctures
Corresponding author: Li Bixin, Hunan No.1 Normal University; Xia Yingdong, Nanjing University of Technology
By Fei Xia, Ying Xu, Bixin Li, Wei Hui, Shiyang Zhang, Lin Zhu, Yingdong Xia, Yonghua Chen and Wei Huang
With the rapid development of information technology, the demand for data processing and storage continues to increase, which puts forward higher requirements for the performance of memory devices. In recent years, organic-inorganic hybrid perovskite materials have attracted extensive attention in photovoltaic devices, optoelectronic devices and memory due to their unique characteristics of mixed electron ions. However, the conventional 3D Perovskite Thin Films need to be prepared by antisolvent in inert atmosphere. In addition, 3D perovskite polycrystalline films are easy to decompose due to defects on the surface and grain boundary, which restricts the storage performance of the device. Therefore, the development of perovskite based resistive memory with simple preparation process, high switch ratio and good storage performance has become one of the hot spots in this field.
Recently, Li Bixin of Hunan No.1 Normal University and Xia Yingdong of Nanjing University of technology constructed a 2D / 3D perovskite heterostructure passivation method to passivate the surface defect state of ch3nh3pbi3 xclx film by spin coating the 3D perovskite ch3nh3pbi3 xclx solution on the surface, which significantly improved the performance of the device. The researchers first used methylamine acetate ionic liquid as solvent to dissolve perovskite precursor, and realized the preparation of high-quality ch3nh3pbi3 xclx perovskite film by one-step spin coating method in air. Then, the Bai solution was spin coated on the surface of the perovskite film, and the chemical reaction between Bai and 3D perovskite molecules was used to generate 2D perovskite interface layer, then 2D / 3D perovskite heterostructure was formed, and the defect state of 3D perovskite surface was passivated (Fig. 1, Fig. 2). Compared with ch3nh3pbi3 xclx based memory device, the switch ratio of the resistive memory device based on this structure is increased by nearly 1000 times (& gt; 103), with lower working voltage (Fig. 3). After 1000 write / erase cycles and 104s constant voltage reading, it can still maintain stable storage performance (Fig. 4). The researchers believe that the introduction of 2D perovskite interface layer reduces the high resistance state current of the device, making the current conduction mechanism of the high resistance state change from space charge limited conductivity to Schottky emission conduction mechanism (Figure 5), thus improving the storage performance. The researchers believe that by introducing 2D perovskite interface layer to passivate the surface defects of hybrid perovskite films, the preparation of high-performance 2D / 3D perovskite heterostructure resistive memory will further promote the development of metal halide perovskite materials in the field of resistive memory devices.
Figure 1. (a) schematic diagram of the preparation process of 2D / 3D perovskite heterostructure memory device and (b) 2D perovskite formation process.
Fig. 2. (a) X-ray diffraction, (b) UV-Vis absorption, and (C-F) SEM images of ch3nh3pbi3 xclx films treated with 0, 1, 3 and 6mg / ml Bai solutions, respectively.
Figure 3. I-V characteristic curve of 2D / 3D perovskite heterostructure memory device based on (a) ch3nh3pbi3 xclx and (b) treatment with 3mg / ml Bai.
Fig. 4. (a) I-V characteristic curve of 2D / 3D perovskite heterostructure memory device after the first and different scanning times to 300 times. (b) Data retention characteristics and (c) durability test chart, reading voltage is 0.25V.
Figure 5. (a) I-V curve of ITO / ch3nh3pbi3 xclx / Al device in high resistance state and low resistance state. (b) I-V curves of 2D / 3D heterostructure perovskite based devices in high and low resistance states. The fitting results of (c) Schottky model ln (I)? (V) 1 / 2 and (d) ohmic model ln (I)? Ln (V) are used for the high and low resistance states.
The research results were published in the recent ACS Applied Materials & interfaces journal. The research was supported by the national key basic research development plan, the National Natural Science Foundation, the special Professor program of Jiangsu Province, and the six talent peak program of Jiangsu Province.
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ACS Appl. Mater. Interfaces 2020, ASAP
Publication Date: March 9, 2020
https://doi.org/10.1021/acsami.9b22732
Copyright ? 2020 American Chemical Society
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