dc.description.abstract | In recent year, organic materials have attracted much attention due to their potential advantages of flexibility, simple process and low cost. Organic memory is an essential device for any electronic logic system to provide or store information for the logic operation, such as radio-frequency identification (RFID)-tags, electronic-papers, and electronic-signage, which strongly demand for a low cost and simple process. The organic memory devices are basically characterized by two types of structure: two terminal bistable and three terminal transistor-like memory devices. The two terminal bistable memory devices offer the advantages of a low operation voltage and a simple process over three terminal transistor-like devices. In chapter 2, we utilize gold nanoparticles embedded polymer to fabricate bistable organic memory. The I–V characteristics show that the device switches from initial OFF-state to ON-state upon application of external electric field. The current transition exhibits in a very narrow voltage range causing an abrupt increase of the current. The conduction mechanism in nanoparticles contained polymer memory was investigated experimentally and theoretically. A trap-filled space-charge-limited current model is proposed to explain the transport mechanism in this memory device.
In chapter 3, we get a stable organic bistable nonvolatile memory (ONBM) by using polymer chain stabilized gold nanoparticles (Au-NPs) in a host polymer as the memory active layer. The TEM images show that the polymer stabilized Au-NPs are well-dispersed in the polymer matrix. We further demonstrate our concept that is feasible for polymer stabilized Au-NPs. This concept enables Au-NPs to be well dispersed in host polymer in order to fabricate the stable devices. This concept enables Au-NPs to be well dispersed in host polymer in order to fabricate the stable devices. The electrical bistability of the device can be precisely controlled by applying a positive voltage pulse or a negative voltage pulse, respectively. This memory can be switched on and off over 1000 times without appreciable performance degradation. In addition, the memory state can retain over 3 days in air environment.
In the chapter 4, a 16-byte addressable ONBM array on the plastic substrate has demonstrated. The memory cell can be switched on and off over 1,000 times and the longest retention time can be estimated to be nearly one year in the air. In the analysis of the mechanical flexibility, we demonstrated that electrical properties of our ONBM were fairly stable during the application of compressive stress down to 5 mm in bending radius. After connecting the ONBM array to the current-sensing circuit, the ONBM array can be correctly addressed and operated, while maintaining low-power consumption. To our best knowledge, this is the first actively addressable ONBM array ever demonstrated.
In the chapter 5, we demonstrate an UV erasable stacked diode-switch organic nonvolatile bistable memory using a polymer-chain stabilized Au nanoparticles on the plastic substrate in the ambient air. The specified DS-ONBM array can be correctly read and avoided crosstalk in a much simplified peripheral circuits. The absorption spectrum of the gold nanoparticles shows ultra-violet (UV) absorption. Therefore, UV light was used to erase data in the DS-ONBM. The function of UV-erasing and diode-switch could greatly simplify the required peripheral circuits. This DS-ONBM was demonstrated to be able to read, write and retain the data and was reusable by UV light illumination. Hence, the UV-erasable DS-ONBM was fully applicable for key applications in printed electronics such as RFID tags. | en_US |