Fabrication of AIE Polymer-Functionalized Reduced Graphene Oxide for Information Storage

Reduced graphene oxide (RGO) has been extensively studied and applied in optoelectronic systems, but its unstable dispersion in organic solvents has limited its application. To overcome this problem, the newly designed and developed aggregation-induced emission (AIE) material poly[(9,9-bis(6-azidohexyl)-9H-fluorene)-alt-(9-(4-(1,2,2-triphenylvinyl)phenyl)-9H-carbazole)] (PAFTC) was covalently grafted onto RGO to produce (PFTC-g-RGO). The solubility of two-dimensional graphene was improved by incorporating it into the backbone of PAFTC to form new functional materials. In resistive random access memory (RRAM) devices, PFTC-g-RGO was used as the active layer material after it was characterized. The fabricated Al/PFTC-g-RGO/ITO device exhibited nonvolatile bistable resistive switching performances with a long retention time of over 104 s, excellent endurance of over 200 switching cycles, and an impressively low turn-ON voltage. This study provides important insights into the future development of AIE polymer-functionalized nanomaterials for information storage.

In Situ Modification of Multi-Walled Carbon Nanotubes with Polythiophene-Based Conjugated Polymer for Information Storage

One-dimensional multi-walled carbon nanotubes (MWNTs) have unique electrical properties, but they are not solution-processable, which severely limits their applications in microelectronic devices. Therefore, it is of great significance to improve the solubility of MWNTs and endow them with new functions by chemical modification. In this work, MWNTs were in situ functionalized with poly[(1,4-diethynyl-benzene)-alt-(3-hexylthiophene)] (PDHT) via Sonogashira-Hagihara polymerization. The obtained material PDHT-g-MWNTs was soluble in conventional organic solvents. By sandwiching a PDHT-g-MWNTs film between Al and ITO electrodes, the fabricated Al/PDHT-g-MWNTs/ITO electronic device exhibited nonvolatile rewritable memory behavior, with highly symmetrical turn-on/off voltages, a retention time of over 10⁴ s, and durability for 200 switching cycles. These findings provide important insights into the development of carbon nanotube-based materials for information storage.

Direct covalent modification of black phosphorus quantum dots with conjugated polymers for information storage

It has long been recognized that a small switching bias window, which is defined as the difference between the switch-on and switch-off voltages (Δ|VON - VOFF|), and a high ON/OFF current ratio would be greatly favorable to reduce the power consumption of memory devices and to decrease the information misreading rate in digital memory devices. In contrast to two-dimensional BP nanosheets, zero dimensional BP quantum dots (BPQDs) show more exciting physical and chemical properties. By using newly synthesized poly[(9,9-dioctyl-9H-fluorene)-alt-(4-(9H-carbazol-9-yl)aniline)] (PFCz-NH2) as the synthetic precursor, a highly soluble diazotated polymer, PFCz-N2+BF4-, was successfully synthesized and used to react with BPQDs under aqueous conditions to give the first conjugated polymer covalently functionalized BPQDs (PFCz-g-BPQDs). The as-prepared Al/PFCz-g-BPQDs/ITO device exhibits excellent nonvolatile rewritable memory performance, with a large ON/OFF current ratio (>107) and low switch-on/off voltages (-0.89/+1.95 V). In contrast, the Al/PFCz-NH2 : BPQDs blend/ITO device also shows a rewritable memory effect, but its ON/OFF current ratio and Δ|VON - VOFF| value are found to be 3 × 103 and 5.47 (Δ|+2.53-2.94|), respectively. This work, which offers an easy one-step strategy for direct covalent functionalization of BPQDs, opens a way to explore more applications of BPQDs.

Recent Progress in Two-Dimensional Nanomaterials for Laser Protection

The Nobel Prize in Physics 2018, “For groundbreaking inventions in the field of laser physics”, went to Arthur Ashkin and Gérard Mourou and Donna Strickland. Their inventions have revolutionized laser physics and greatly promoted the development of laser instruments, which have penetrated into many aspects of people’s daily lives. However, for the purpose of protecting human eyes or optical instruments from being damaged by both pulsed and continuous wave laser radiation, the research on laser protective materials is of particular significance. Due to the intriguing and outstanding physical, chemical, and structural properties, two-dimensional (2D) nanomaterials have been extensively studied as optical limiting (OL) materials owing to their broadband nonlinear optical (NLO) response and fast carrier relaxation dynamics that are important for reducing the laser intensity. This review systematically describes the OL mechanisms and the recent progress in 2D nanomaterials for laser protection.