石墨烯量子点的定义
石墨烯量子点(Graphene Quantum Dots, GQDs)是横向尺寸小于50 nm、厚度为0.5-1.0nm的石墨烯(图1)。石墨烯量子点的制备由top-down和bottom-up两种途径,top-down方法主要以石墨烯或石墨为前驱体通过化学、电化学或物理法将横向尺寸减小到几个纳米,bottom-up方法主要以含苯环的小分子通过水热、高温气相沉积或电化学合成等方法实现几个纳米的量子点。
图1 石墨烯量子点的表征
(a)石墨烯量子点的TEM图像(插图为石墨烯量子点的横向尺寸分布)
(b)石墨烯量子点高分辨TEM图像
(c)石墨烯量子点的AFM图像及对应高度分析。Chem. Mater., 2015, 27, 2004-2011.
石墨烯量子点的物性
化学稳定性方面,石墨烯量子点具有石墨烯的sp2构型原子排列结构,在化学稳定性方面,石墨烯量子点具有较之于其它量子点材料所不具备的化学稳定性,能够承受强酸、强碱和较高温度的极端环境。
带隙性质方面,石墨烯是一种零带隙类半导体材料,当石墨烯的横向尺寸减小到量子尺度(<100 nm)时,石墨烯中的π电子发生局域化,其带隙随之打开,通过尺寸调控、形貌调控、边缘结构调控及掺杂等手段,石墨烯量子点的带隙可实现从0 eV 到5 eV之间的宽幅调制。
光学性质方面,石墨烯量子点具有显著的光致发光性能,其具有高荧光稳定性、高抗离子干扰能力和高抗光漂白能力(图2)。同时,通过简单的手段对石墨烯量子点尺寸与化学结构(边缘/表面基团修饰、晶格异质原子掺杂)的控制可实现石墨烯量子点发光波长的有效调控,从而实现石墨烯量子点可见光全光谱发光调制。
图2 石墨烯量子点的荧光性能
石墨烯量子点(N-GQD)
水溶液与荧光染料罗丹明B(RhB)
乙醇溶液在可见光下(左图)及紫外光下(右图)的照片
其中N-GQD的荧光量子产率为0.74,RhB的荧光量子产率为0.68。Part. Part. Syst. Charact., 2015, 32, 434-440
催化性能方面,石墨烯量子点具有高比表面积及边缘原子比例,边缘原子的占比可以高达20%,这使得该类材料在催化过程中具有最高的暴露活性位点。这一系列优异的界面性质使石墨烯量子点材料在能源应用领域(锂离子电池、超级电容器、光催化产氢/氧等)以及环境保护领域(光催化降解)具有极高的应用价值。
生物性能方面,石墨烯量子点作为典型的碳基半导体材料,其生物安全性较之传统荧光材料(荧光染料、II-IV族量子点等)更高,具有优异的生物相容性。同时,石墨烯量子点的小尺寸使其在细胞荧光成像中更易于进入细胞内,从而实现胞内环境成像。
石墨烯量子点的应用
发光器件
石墨烯量子点通过掺杂、表面修饰等方式对其荧光性能进行有效调控后,可用于碳基发光器件的构建(图3),较之于传统LED发光器件,石墨烯量子点为发光材料的碳基发光器件具有更好的稳定性,同时避免了潜在的重金属污染。
图3 基于石墨烯量子点的高效绿光LED器件 Appl. Phys. Express, 2017, 10, 032102
光学探针
石墨烯量子点通过掺杂、表面基团修饰等手段,可实现离子、生物分子、自由基等的高灵敏检测。检出限可达10-6 M至10-12 M(图4),该方案较之于传统的检测技术,具有更高的灵敏度和抗干扰能力。
图4 基于Se掺杂石墨烯量子点所构建的细胞中羟基自由基-还原型谷胱甘肽氧化还原过程的荧光探针技术。Chem. Mater., 2015, 27, 2004-2011
生物成像
石墨烯量子点兼具良好的生物相容性、稳定性、抗干扰能力和荧光性能。因此,石墨烯量子点可作为一种理想的细胞荧光成像剂应用于细胞、组织成像(图5)。
图5 基于绿光N掺杂石墨烯量子点在细胞成像中的应用
(a)不同浓度N掺杂石墨烯量子点的细胞毒性
(b)可见光下N掺杂石墨烯量子点处理后的组织细胞的显微图像
(c)对应的荧光显微图像。Part. Part. Syst. Charact., 2015, 32, 434-440
肿瘤诊疗
石墨烯量子点具有丰富的表面基团,通过表面靶向剂修饰、药物担载等手段,可实现基于石墨烯量子点的肿瘤诊断与靶向治疗。同时,利用石墨烯量子点优异的荧光性能,在靶向治疗的同时,能够实现肿瘤组织的实时荧光监控,实现全治疗过程的长效可视化。
图6 基于绿光N掺杂石墨烯量子点的肿瘤治疗方案
(a)绿光N掺杂石墨烯量子点在小鼠肿瘤包块中的选择性富集
(b)N掺杂石墨烯量子点与自噬调节剂连用后30天中对小鼠肿瘤模型的治疗效果
(c)N掺杂石墨烯量子点与自噬调节剂连用对小鼠30天存活率的提升。Adv. Funct. Mater., 2018, 1800881
中科院上海微系统所发表的石墨烯量子点相关论文列表
1. Emancipating target-functionalized carbon dots from autophagy vesicles for visualized tumor therapy, Advanced Functional Materials 2018, 1800881.
2. Facile and Highly Effective Synthesis of Controllable Lattice Sulfur-Doped Graphene Quantum Dots via Hydrothermal Treatment of Durian, ACS Applied Materials & Interfaces, DOI: 10.1021/acsami.7b16002.
3. Highly Active Black TiO2/N-doped Graphene Quantum Dots Nanocomposites For Sunlight Driven Photocatalytic Sewage Treatment, ChemistrySelect 3 (2018) 201-206.
4. Electrochemical Cutting in Weak Aqueous Electrolyte: the Strategy for Controllable and Efficient Preparation of Graphene Quantum Dots, Langmuir 34 (2018) 250-258.
5. C3N - a 2D crystalline, hole-free, tunable-narrow-bandgap semiconductor with high on-off current ratio and ferromagnetic properties, Advanced Materials 29 (2017) 1605625.
6. Robust GQDs Modified Thermally Reduced Graphene Oxide Membranes for Ultrafast and Long-Term Purification of Dye-Wasted Water, Advanced Materials Interfaces, 4 (2017) 1700209.
7. Insights into oxidation mechanism of sp2-sp3 hybrid carbon material: preparation of water-soluble 2D porous conductive network and detectable molecule separation, Langmuir 33 (2017) 913-919.
8. Tunable amplified spontaneous emissionin graphene quantum dots doped cholesteric liquid crystals, Nanotechnology 28 (2017) 245202.
9. 石墨烯量子点:石墨烯材料体系中的明珠,丁古巧等,张江科技评论 3 (2017) 35-36.
10. Carbon Dioxide Hydrogenation over a Metal-Free Carbon Based Catalyst,ACS Catalysis 7 (2017) 4497-4503.
11. Graphene quantum dot incorporated perovskite films: passivating grain boundaries and facilitating electron extraction, Physical Chemistry Chemical Physics, 19 (2017) 6057-6063.
12. Fabrication of centimeter-scale light emitting diode with improved performance based on fat soluble graphene quantum dots, Applied Physics Express 10 (2017) 032102.
13. Facile Synthesis of Highly Graphitized Nitrogen-Doped Carbon Dots and Carbon Sheets with Solid-State White-Light Emission, Materials Letters 195 (2017) 58-61.
14. A Metal-Free Electrocatalyst for Carbon Dioxide Reduction to Multi-Carbon Hydrocarbons and Oxygenates, Nature Communications 7 (2016) 13869.
15. Supramolecular recognition control of polyethylene glycol modified N-doped graphene quantum dots: tunable selectivity for alkali and alkaline-earth metal ions, Analyst 141 (2016) 1052-1059.
16. Ultrafast adsorption and selective desorption of aqueous aromatic dyes by graphene sheets modified by graphene quantum dots, Nanotechnology 24 (2016) 245703.
17. Green, simple and large scale synthesis of N-doped graphene quantum dots with uniform edge groups by electrochemical bottom-up synthesis, RSC Advances 6 (2016) 82648-82653.
18. 3D periodic multiscale TiO2 architecture: a platform decorated with graphene quantum dots for enhanced photoelectrochemical water splitting, Nanotechnology 27 (2016) 115401.
19. Enhanced monolayer MoS2/InP heterostructure solar cells by graphene quantum dots, Applied Physics Letters 108 (2016) 163901.
20. Processable aqueous dispersions of graphene stabilized by graphene quantum dots, Chemistry of Materials 27 (2015) 218-226.
21. Selenium doped graphene quantum dots as an ultrasensitive redox fluorescent switch, Chemistry of Materials, 27 (2015) 2004-2011.
22. Negative induction effect of graphite N on graphene quantum dots: tunable band gap photoluminescence, Journal of Materials Chemistry C, 3 (2015) 8810-8816.
23. A new mild, clean and high-efficient method for preparation of graphene quantum dots without by-products, Journal of Materials Chemistry B, 3 (2015) 6871-6876.
24. Aromatic-N Doping Dominant Ultra-High Quantum Yield of Graphene Quantum Dots, Particle & Particle Systems Characterization. 32 (2015) 434-440.
25. Graphene Quantum Dots Coating Enhances Lithium Storage Performance of CuO Nanowires, Advanced Materials Interfaces 2 (2015) 1400499.
26. The emission wavelength dependent photoluminescence lifetime of the N-doped graphene quantum dots. Applied Physics Letters 107 (2015) 241905.
27. Triphenylphosphine modified graphene quantum dots: spectral modulation for full spectrum of visible light with high quantum yield, RSC Advances 5(2015) 33347.
28. Deep Ultraviolet Emission Photoluminescence and High Luminescece Efficiency of Ferric Passivated Graphene Quantum Dots: Strong Negative Inductive Effect of Fe, Synthetic Metals, 209 (2015) 468-472.
29. Large-scale Fabrication of Heavy Doped Carbon Quantum Dots with Tunable-photoluminescence and Sensitive Fluorescent Detection, Journal of Materials Chemistry A 2 (2014) 8660.
中科悦达提供的石墨烯量子点产品规格
中科悦达(上海)材料科技有限公司针对石墨烯量子点在肿瘤诊疗、电致发光等领域中的应用需求开发了多样化的石墨烯量子点产品,包括蓝光、黄绿光、红光水溶性石墨烯量子点粉体;水溶性氧化石墨烯量子点粉体;蓝光、绿光、黄光、白光石墨烯量子点荧光粉。
同时,中科悦达(上海)材料科技有限公司针对客户实际应用需求,可实现石墨烯量子点多样化结构修饰,提供多样化的石墨烯量子点宏量生产、修饰技术解决方案。
一、水溶性石墨烯量子点粉体
※ 基本物性
※ 光学性质
※ 主要用途
1. 肿瘤诊断、治疗及诊疗一体化
2. 肿瘤标志物检测试剂盒
3. 干细胞辅助治疗技术开发
4. 光电转换、热电转换、光催化触媒
5. 发光涂层、电致发光器件
6. 石墨烯等二维材料水相辅助分散
7. 海水淡化、超滤
※ 相关文献
1. Advanced Functional Materials, 2018, 28 (30), 1800881.
2. Nano Letters, 2010, 10(5), 1869-1873.
3. Chemistry of Materials, 2014, 27, 218-226.
4. Chemistry of Materials, 2015, 27 (6), 2004-2011.
5. Journal of Materials Chemistry A, 2014, 2 (23), 8660-8667.
6. Journal of Materials Chemistry A, 2019, 7 (10), 5740-5747.
7. Particle & Particle Systems Characterization, 2015, 32 (4), 434-440.
8. Advanced Energy Materials, 2013, 3(8), 997-1003.
二、石墨烯量子点荧光粉
※ 基本物性
※ 光学性质
※ 主要用途
1. 环保型LED荧光粉
2. 环保型高级荧光防伪油墨(用于烟酒及食品等荧光防伪技术)
3. 荧光快速检测试纸
※ 相关文献
1. JOURNAL OF MATERIALS CHEMISTRY, 2012, 22(42), 22378-22381.
2. Particle & Particle Systems Characterization, 2016, 33(2), 70-74.
3. Nature Communications, 2018, 9, 2249.
4. Nano Today, 2014, 9(5), 590-60.
5. ACS Nano, 2013, 7(12), 11234-11241.
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