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By doping a dielectric layer material and improving the device's structure, the electrical characteristics of a memristor can be effectively adjusted, and its application field can be expanded. In this study, graphene quantum dots are embedded in the dielectric layer to improve the performance of a starch-based memristor, and the PMMA layer is introduced into the upper and lower interfaces of the dielectric layer. The experimental results show that the switching current ratio of the Al/starch: GQDs/ITO device was 102 times higher than that of the Al/starch/ITO device. However, the switching current ratio of the Al/starch: GQDs/ITO device was further increased, and the set voltage was reduced (−0.75 V) after the introduction of the PMMA layer. The introduction of GQDs and PMMA layers can regulate the formation process of conductive filaments in the device and significantly improve the electrical performance of the memristor. [ABSTRACT FROM AUTHOR]

As artificial synapse devices, memristors have attracted widespread attention in the field of neuromorphic computing. In this paper, Al/polymethyl methacrylate (PMMA)/egg albumen (EA)–graphene quantum dots (GQDs)/PMMA/indium tin oxide (ITO) electrically/optically tunable biomemristors were fabricated using the egg protein as a dielectric layer. The electrons in the GQDs were injected from the quantum dots into the dielectric layer or into the adjacent quantum dots under the excitation of light, and the EA–GQDs dielectric layer formed a pathway composed of GQDs for electronic transmission. The device successfully performed nine brain synaptic functions: excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), short-term potentiation (STP), short-term depression (STD), the transition from short-term plasticity to long-term plasticity, spike-timing-dependent plasticity (STDP), spike-rate-dependent plasticity (SRDP), the process of learning, forgetting, and relearning, and Pavlov associative memory under UV light stimulation. The successful simulation of the synaptic behavior of this device provides the possibility for biomaterials to realize neuromorphic computing. [ABSTRACT FROM AUTHOR]

Al/PMMA/SY : GQDs/PMMA/ITO devices with multilayer structures were fabricated by imbedding PMMA at both ends of soybean (SY) and graphene quantum dot (GQD) dielectric layers, which not only improved the stability of the devices but also reduced the threshold voltage and power consumption. A single unit of the device can complete the logical "AND" and "OR" operations to realize the memory calculation, which provides a new way to overcome the memory bottleneck of computer systems. [ABSTRACT FROM AUTHOR]

Biomaterials have attracted attention as a major material for biodegradable and transient electronic devices. In this work, biocompatible gelatin-doped graphene quantum dot films are reported as active layer switching memories with good electrical properties and physical transient properties. Such nonvolatile memory devices have write-once-read-many electrical properties and a concentrated distribution of low-resistance and high-resistance states. It provides a solution for the current obstacle of resistive memory storage and computing integration. Based on the sensitivity of the device to ultraviolet light, the "OR gate" logic operation is completed. Furthermore, the active layer can be dissolved in deionized water within 15 min, and the gelatin substrate-based device can be destroyed immediately in water, indicating the potential biodegradation and physical transient properties of our fabricated device. Biocompatible memory devices are environmentally friendly, sustainable for safe storage, and low-cost, making them ideal for storage applications. [ABSTRACT FROM AUTHOR]

In this paper, a floating-gate flexible nonvolatile memory is reported that is composed of natural biological materials, namely, silkworm hemolymph, graphene quantum dots as the floating-gate layer, and polymethyl methacrylate (PMMA) as the insulating layer. The device has a high ON/OFF current ratio (4.76 × 106), a low setting voltage (<−1.75 V), and good durability and retention ability. The device has two storage characteristics, namely, Flash and WORM, which can be effectively and accurately controlled by adjusting the limiting current during device setting. The resistance switching characteristics are the result of the formation and fracture of conductive filaments. The floating-gate flexible bioresistive random access memory prepared in this paper provides a new idea for the development of multifunctional and biocompatible flexible memory. [ABSTRACT FROM AUTHOR]

Physical transient electronics have attracted more attention as the basis for building green electronics and biomedical devices. However, there are difficulties in selecting materials for the fabricated devices to take into account both biodegradability and high performance. In this paper, a physically transient resistive random-access memory (RRAM) device was fabricated by using egg protein and graphene quantum dot composites as active layers. The sandwich structure composed of Al/EA:GQD/ITO shows a good write-once-multiple-read memory characteristic, and the introduced GQD improves the switching current ratio of the device. By using the sensitivity of GQDs to ultraviolet light, the logic operation of the "OR gate" is completed. Furthermore, the device exhibits a physical transient behavior and good biodegradability due to the dissolution behavior in deionized water. These results suggest that the device is a favorable candidate for the construction of memory elements for transient electronic systems. [ABSTRACT FROM AUTHOR]

Nanocarbon materials have the advantages of biocompatibility, thermal stability and chemical stability and have shown excellent electrical properties in electronic devices. In this study, Al/MWCNT:GQD/ITO memristors with rewritable nonvolatile properties were prepared based on composites consisting of multiwalled carbon nanotubes (MWCNTs) and graphene quantum dots (GQDs). The switching current ratio of such a device can be tuned in two ways. Due to the ultraviolet light sensitivity of GQDs, when the dielectric material is illuminated by ultraviolet light, the charge capture ability of the GQDs decreases with an increasing duration of illumination, and the switching current ratio of the device also decreases with an increasing illumination duration (103–10). By exploiting the charge capture characteristics of GQDs, the trap capture level can be increased by increasing the content of GQDs in the dielectric layer. The switching current ratio of the device increases with increasing GQD content (10–103). The device can be programmed and erased more than 100 times; the programmable switching state can withstand 105 read pulses, and the retention time is more than 104 s. This memristor has a simple structure, low power consumption, and enormous application potential for data storage, artificial intelligence, image processing, artificial neural networks, and other applications. [ABSTRACT FROM AUTHOR]

In this study, Al/Scindapsus aureus (SA)/ITO and Al/polymethyl methacrylate (PMMA)/SA:graphene quantum dots (GQDs)/PMMA/ITO devices of different memory types and with different electrical characteristics were fabricated based on SA. Al/SA/ITO devices have bipolar resistance switching characteristics with a switching current ratio of 103 and a holding time of more than 104 s. When an Al/SA/ITO device is fabricated on a flexible substrate, the device still maintains stable resistance switching characteristics. After the addition of GQDs into the dielectric layer, the switching current ratio is increased (>105). Accordingly, Al/PMMA/SA:GQDs/PMMA/ITO resistive memory was fabricated based on SA and GQD composites. Al/PMMA/SA:GQDs/PMMA/ITO/glass devices also show bipolar resistance switching characteristics; a single memory cell can be switched more than 200 times continuously, with the lowest threshold voltage, and the holding time is greater than 2 × 104 s. A cell of the Al/PMMA/SA:GQDs/PMMA/ITO/PET memristors fabricated in this study can exhibit both bipolar and write-once-read-many-times (WORM) memory characteristics under different limited currents. The results show that SA is a promising biomaterial for memory fabrication, and this research opens up a new avenue for the application and development of memory with multiple functions and flexible wearable electronic devices. [Display omitted] • Flexible resistive memory with different storage properties is fabricated based on the biomaterial Scindapsus aureus. • By doping with graphene quantum dots, the switching current ratio is increased, and the data misreading rate is reduced. • The device has more stable resistance switching behavior and a reduced set voltage, enabling low-power storage. • The devices fabricated on PET can exhibit both flash and WORM memory characteristics under different limited currents. [ABSTRACT FROM AUTHOR]