Study On Electrically Bistable Characteristics Based On Inorganic Nanocrystal/Polymer Composite Films

To overcome the limitation of the exploitation for the inorganic semiconductor memory devices, it is necessary to develop new types of memory materials, which has been extensively studied in the past few decades. Organic materials become promising candidates in electrically memory devices due to their low-cost, flexible, large-capacity data storage and so on. However, only one material has lacked behind the development steps with the advance of the science and technology, and the composite materials have dominated the trend of the development of the materials. Currently, incorporation of inorganic materials into polymer to form polymer-based composite materials have become the focus of the area of memory devices, owing to the breakthrough of the synthesis and optoelectronic properties of the inorganic nanocrystals.In this paper, inorganic nanoparticles capped by dodecanethiol were prepared by chemical method. Electrically bistable devices have been fabricated using nanocomposite films consisting of nanoparticles and a semiconducting polymer by a simple spin-coating method. Reproducible electrical bistability were observed in current-voltage characteristics. The effects on the devices and the working priciples of the electrically bistable devices have been studied. The main contents are listed as follows:1. Cu2S and Ag nanoparticels were prepared using a one-pot reaction method, in which dodecanethiol was used as sulfide sources and capping ligands.. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements have been used to characterize the crystal structure and morphology of the as-obtained samples..2. Electrically bistable devices were fabricated based on blends of Gu2S nanocrystals and a semiconducting polymer poly (N-vinylcarbazole) (PVK) using a simple spin-coating method. Current-voltage (I-V) characteristics were employed to study the electrical bistability properties of the devices by applying different amplitude of sweeping voltages and varying the mass ratios of Cu2S nanocrystals to polymer. The electrical transition from a low conducting state (OFF state) to a high conducting state (ON state) was discussed.3. An electrically bistable device was fabricated based on the nanocomposites containing Ag nanoparticles and PVK prepared by a spin coating method. Current-voltage (I-V) measurements were preformed to study the electrical properties of the bistable devices by applying different amplitude of sweeping voltages and varying the mass ratios of Ag nanocrystals to polymer. And a large reproducible electrical bistability and NDR behavior was observed. To further understand the current switching from the ON state to the OFF state, we have tried to fit the I-V characteristics in both states in terms of different theoretical models.