Direct synthesis of graphene quantum dots from multilayer graphene flakes through grinding assisted co-solvent ultrasonication for all-printed resistive switching arrays
| Autor: | Ghayas Uddin Siddiqui, Kiju Um, Kyung Hyun Choi, Young Jin Yang, Kang Taek Lee, Junaid Ali |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Materials science Photoluminescence Graphene General Chemical Engineering Nanotechnology 02 engineering and technology General Chemistry Polymer 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Exfoliation joint 0104 chemical sciences law.invention symbols.namesake chemistry Quantum dot law symbols Fourier transform infrared spectroscopy 0210 nano-technology High-resolution transmission electron microscopy Raman spectroscopy |
| Zdroj: | RSC Advances. 6:5068-5078 |
| ISSN: | 2046-2069 |
| Popis: | Graphene quantum dots (GQD) with diameters as small as ∼2 nm were synthesized by an efficient chemo-mechanical technique. This involved mortar grinding and ultra-sonication as a means of mechanical energy transfer, while N-methyl-pyrrolidone and 1,2-dichlorobenzene were used for exfoliation and breakdown of graphene nanoplatelets. High resolution transmission electron microscopy images showed that the solution-based GQDs were about 2–4 nm in size, and had a crystalline lattice parameter of 0.24 nm. The technique proved useful for extracting GQDs of the desired size. XRD, Raman and FTIR spectroscopy were used to analyze the quality of the graphene structure within the GQDs. The UV responsive GQDs had a band-gap of 2.6 eV and stronger photoluminescence at 350 nm compared to lower wavelengths of laser excitation. An all-printed 2 × 2 array of memristors based on a GQD embedded polymer matrix fabricated on a flexible PET substrate showed an OFF/ON ratio of just over 7 when read at 100 mV, stable retention despite a high compliance current for ∼100 switching cycles, and a robustness of 200 bending cycles up to 1.5 cm bending diameter without compromise on resistive switching states. |
| Databáze: | OpenAIRE |
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