奈米粒子因其高比表面積和奈米尺寸而具有獨特的物理及化學性質，其形狀、尺寸等影響了他們的光學性質、反應性、韌性等性能，由於這些優異的特性因此適合用於各種像是催化1-2、成像3、醫學4和能源5以及環境6的應用，其在表面電漿共振的特性應用更為受重視。本研究以化學還原法合成出尺寸為64奈米的方形銅奈米粒子，在所測試的實驗參數中，發現溫度對尺寸變化的影響最大、濃度次之，將兩者相互搭配可合成出尺寸為30奈米的方形銅奈米粒子而不改變其形貌。使用反相微乳液法，在銅奈米外包覆二氧化矽殼層，避免銅奈米粒子的團聚及氧化，同時保留其光學性質，找出形成單分散且無空矽殼的最佳化參數為 pH 11.2的Na2CO3(aq)，矽源濃度為0.093 M，界面活性劑為0.263 M及銅奈米粒子在2毫升環己烷中的濃度為0.024 M，並發現同樣的包覆參數適用於30及64奈米的銅奈米金屬核，藉由時間及溫度的調整合成出不同的殼層厚度做為隔離層調控金屬核螢光分子的間距。利用二氧化矽容易官能化的優點，將其表面修飾3-氨基丙基三以氧基矽烷使帶有胺基，和螢光分子鍵結探討銅奈米粒子在電漿增強螢光方面的適用性。

Nanoparticles have unique physical and chemical properties, such as optical properties, reactivity, toughness, and so on, due to their high specific surface area and nanoscale size. Therefore, they are promising materials for various applications. The applications related to the surface plasmon resonance of the nanoparticles are especially important. We used a disproportionation reaction to synthesize copper nanocubes in this study. Copper nanoparticles were applied to investigate the performance of plasmon-enhanced fluorescence. Copper nanocubes with different sizes were prepared by adjusting the reaction temperature and the concentration of copper precursor. Here, we applied the reverse microemulsion method to realize the silica coating of Cu NPs for preparing Cu@SiO2 core-shell structure. The silica layer not only prevents aggregation and oxidation of Cu NPs also maintains their optical properties. The best condition to obtain monodisperse Cu@SiO2 NPs for 30-nm Cu nanocubes without core free particles involves the usage of pH 11.2 Na2CO3(aq) as the alkaline catalyst and the concentrations of silane, surfactant, and Cu NPs are 0.093, 0.263 and 0.024 M, respectively, in 2 mL cyclohexane. Above conditions were also suitable for coating 64-nm Cu nanocubes. By adjusting reaction time and temperature for silica coating, we can get different shell thicknesses as a spacer layer to regulate the distance between metal nanoparticle and fluorophore. Amino functionalized Cu@SiO2 NPs were used to conjugate with a fluorophore to investigate the feasibility of Cu@SiO2 as plasmon-enhanced fluorescence probes.

1. Peng, K.; Fu, L.; Yang, H.; Ouyang, J., Perovskite LaFeO3/Montmorillonite Nanocomposites: Synthesis, Interface Characteristics and Enhanced Photocatalytic Activity. Scientific Reports 2016, 6 , 19723.
2. Ali, S.; Khan, I.; Khan, S. A.; Sohail, M.; Ahmed, R.; Rehman, A. u.; Ansari, M. S.; Morsy, M. A., Electrocatalytic Performance of Ni@Pt Core–Shell Nanoparticles Supported on Carbon Nanotubes for Methanol Oxidation Reaction. Journal of Electroanalytical Chemistry 2017, 795, 17-25.
3. Khlebtsov, N. G.; Dykman, L. A., Optical Properties and Biomedical Applications of Plasmonic Nanoparticles. Journal of Quantitative Spectroscopy and Radiative Transfer 2010, 111, 1-35.
4. Bañobre-López, M.; Teijeiro, A.; Rivas, J., Magnetic Nanoparticle-Based Hyperthermia for Cancer Treatment. Reports of Practical Oncology & Radiotherapy 2013, 18, 397-400.
5. Tiwari, J. N.; Tiwari, R. N.; Kim, K. S., Zero-Dimensional, One-Dimensional, Two-Dimensional and Three-Dimensional Nanostructured Materials for Advanced Electrochemical Energy Devices. Progress in Materials Science 2012, 57, 724-803.
6. Peer Reviewed: Environmental Technologies at the Nanoscale. Environmental Science & Technology 2003, 37, 102A-108A.
7. Ray, K.; Badugu, R.; Lakowicz, J. R., Distance-Dependent Metal-Enhanced Fluorescence from Langmuir−Blodgett Monolayers of Alkyl-NBD Derivatives on Silver Island Films. Langmuir 2006, 22 , 8374-8378.
8. Reineck, P.; Gómez, D.; Ng, S. H.; Karg, M.; Bell, T.; Mulvaney, P.; Bach, U., Distance and Wavelength Dependent Quenching of Molecular Fluorescence by Au@SiO2 Core–Shell Nanoparticles. ACS Nano 2013, 7, 6636-6648.
9. Cui, Q.; He, F.; Li, L.; Möhwald, H., Controllable Metal-Enhanced Fluorescence in Organized Films and Colloidal System. Advances in Colloid and Interface Science 2014, 207, 164-177.
10. Willets, K. A.; Van Duyne, R. P., Localized Surface Plasmon Resonance Spectroscopy and Sensing. Annual Review of Physical Chemistry 2007, 58, 267-297.
11. Mayer, K. M.; Hafner, J. H., Localized Surface Plasmon Resonance Sensors. Chemical Reviews 2011, 111, 3828-3857.
12. Li, M.; Cushing, S. K.; Wu, N., Plasmon-Enhanced Optical Sensors: A Review. Analyst 2015, 140, 386-406.
13. Geddes, C.; Lakowicz, J., Metal-Enhanced Fluorescence. Journal of Fluorescence 2002, 12, 121-129.
14. Jeong, Y.; Kook, Y.-M.; Lee, K.; Koh, W.-G., Metal Enhanced Fluorescence (MEF) for Biosensors: General Approaches and A Review of Recent Developments. Biosensors and Bioelectronics 2018, 111, 102-116.
15. Lakowicz, J. R.; Ray, K.; Chowdhury, M.; Szmacinski, H.; Fu, Y.; Zhang, J.; Nowaczyk, K., Plasmon-Controlled Fluorescence: A New Paradigm in Fluorescence Spectroscopy. Analyst 2008, 133, 1308-1346.
16. 徐良敏; 張正龍; 蔡曉燕; 鄭海榮, 金屬表面螢光增強的物理增強機制. 發光學報 2009, 30, 373-378.
17. Radiative-Decay Engineering: Surface Plasmon-Coupled Emission. In Principles of Fluorescence Spectroscopy, Lakowicz, J. R., Ed. Springer US: Boston, MA, 2006; pp 861-871.
18. Radiative Decay Engineering: Metal-Enhanced Fluorescence. In Principles of Fluorescence Spectroscopy, Lakowicz, J. R., Ed. Springer US: Boston, MA, 2006; pp 841-859.
19. Tsai, Y.-C.; Lin, C.-F.; Chang, J.-W., Controlling Spontaneous Emission with the Local Density of States of Honeycomb Photonic Crystals. Optical Review 2009, 16, 347-350.
20. Ji, X.; Xiao, C.; Lau, W.-F.; Li, J.; Fu, J., Metal Enhanced Fluorescence Improved Protein and DNA Detection by Zigzag Ag Nanorod Arrays. Biosensors and Bioelectronics 2016, 82, 240-247.
21. Sun, B.; Wang, C.; Han, S.; Hu, Y.; Zhang, L., Metal-Enhanced Fluorescence-Based Multilayer Core–Shell Ag-Nanocube@SiO2@PMOs Nanocomposite Sensor for Cu2+ Detection. RSC Advances 2016, 6, 61109-61118.
22. Livage, J., Basic Principles of Sol-Gel Chemistry. In Sol-Gel Technologies for Glass Producers and Users, Aegerter, M. A.; Mennig, M., Eds. Springer US: Boston, MA, 2004; pp 3-14.
23. Chang, C.-L.; Fogler, H. S., Kinetics of Silica Particle Formation in Nonionic W/O Microemulsions from TEOS. AIChE Journal 1996, 42, 3153-3163.
24. Stöber, W.; Fink, A.; Bohn, E., Controlled Growth of Monodisperse Silica Spheres in the Micron Size Range. Journal of Colloid and Interface Science 1968, 26, 62-69.
25. Han, Y.; Lu, Z.; Teng, Z.; Liang, J.; Guo, Z.; Wang, D.; Han, M.-Y.; Yang, W., Unraveling the Growth Mechanism of Silica Particles in the Stöber Method: In Situ Seeded Growth Model. Langmuir 2017, 33, 5879-5890.
26. Chaudhary, A.; Gaur, P.; Barman, M.; Mishra, R.; Singh, M., A Review on Microemulsion A Promising Optimising Technique Used as A Novel Drug Delivery System. International Research Journal Of Pharmacy 2018, 9, 47-52.
27. Migahed, M. M. A.; Attya, M. M.; Rashwan, S. M.; El-Raouf, M.; Al-Sabagh, A., Synthesis of Some Novel Non Ionic Surfactants Based on Tolyltriazole and Evaluation Their Performance as Corrosion Inhibitors for Carbon Steel. Egyptian Journal of Petroleum 2013, 22, 149–160.
28. Garti, N.; Aserin, A.; Ezrahi, S.; Wachtel, E., Water Solubilization and Chain Length Compatibility in Nonionic Microemulsions. Journal of Colloid and Interface Science 1995, 169, 428-436.
29. Ding, H. L.; Zhang, Y. X.; Wang, S.; Xu, J. M.; Xu, S. C.; Li, G. H., Fe3O4@SiO2 Core/Shell Nanoparticles: The Silica Coating Regulations with a Single Core for Different Core Sizes and Shell Thicknesses. Chemistry of Materials 2012, 24, 4572-4580.
30. Baskaran, S., Structure and Regulation of Yeast Glycogen Synthase. 2010.
31. Guo, H.; Chen, Y.; Cortie, M. B.; Liu, X.; Xie, Q.; Wang, X.; Peng, D.-L., Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties. The Journal of Physical Chemistry C 2014, 118, 9801-9808.
32. Tee, S. Y.; Ye, E.; Pan, P. H.; Lee, C. J. J.; Hui, H. K.; Zhang, S.-Y.; Koh, L. D.; Dong, Z.; Han, M.-Y., Fabrication of Bimetallic Cu/Au Nanotubes and Their Sensitive, Selective, Reproducible and Reusable Electrochemical Sensing of Glucose. Nanoscale 2015, 7, 11190-11198.
33. Ye, E.; Zhang, S.-Y.; Liu, S.; Han, M.-Y., Disproportionation for Growing Copper Nanowires and their Controlled Self-Assembly Facilitated by Ligand Exchange. Chemistry (Weinheim an der Bergstrasse, Germany) 2011, 17, 3074-7.
34. Yang, H.-J.; He, S.-Y.; Tuan, H.-Y., Self-Seeded Growth of Five-Fold Twinned Copper Nanowires: Mechanistic Study, Characterization, and SERS Applications. Langmuir 2014, 30, 602-610.
35. Guo, H.; Chen, Y.; Ping, H.; Jin, J.; Peng, D.-L., Facile Synthesis of Cu and Cu@Cu–Ni Nanocubes and Nanowires in Hydrophobic Solution in the Presence of Nickel and Chloride Ions. Nanoscale 2013, 5, 2394-2402.
36. Chu, C. R.; Lee, C.; Koo, J.; Lee, H. M., Fabrication of Sintering-Free Flexible Copper Nanowire/Polymer Composite Transparent Electrodes with Enhanced Chemical and Mechanical Stability. Nano Research 2016, 9, 2162-2173.
37. Baldan, A., Review Progress in Ostwald Ripening Theories and Their Applications to the γ′-Precipitates in Nickel-Base Superalloys Part II Nickel-Base Superalloys. Journal of Materials Science 2002, 37, 2379-2405.
38. Bastús, N. G.; Comenge, J.; Puntes, V., Kinetically Controlled Seeded Growth Synthesis of Citrate-Stabilized Gold Nanoparticles of up to 200 nm: Size Focusing versus Ostwald Ripening. Langmuir 2011, 27, 11098-11105.
39. Yang, H.-J.; He, S.-Y.; Chen, H.-L.; Tuan, H.-Y., Monodisperse Copper Nanocubes: Synthesis, Self-Assembly, and Large-Area Dense-Packed Films. Chemistry of Materials 2014, 26, 1785-1793.
40. Crane, C. C.; Wang, F.; Li, J.; Tao, J.; Zhu, Y.; Chen, J., Synthesis of Copper–Silica Core–Shell Nanostructures with Sharp and Stable Localized Surface Plasmon Resonance. The Journal of Physical Chemistry C 2017, 121, 5684-5692.
41. Abeywickrama, T.; Sreeramulu, N. N.; Xu, L.; Rathnayake, H., A Versatile Method to Prepare Size- and Shape-Controlled Copper Nanocubes Using an Aqueous Phase Green Synthesis. RSC Advances 2016, 6, 91949-91955.
42. Zheng, P.; Tang, H.; Liu, B.; Kasani, S.; Huang, L.; Wu, N., Origin of Strong and Narrow Localized Surface Plasmon Resonance of Copper Nanocubes. Nano Research 2018, 1-6.
43. Bagwe, R. P.; Yang, C.; Hilliard, L. R.; Tan, W., Optimization of Dye-Doped Silica Nanoparticles Prepared Using a Reverse Microemulsion Method. Langmuir 2004, 20, 8336-8342.
44. Jaramillo, N.; Paucar, C.; García, C., Influence of The Reaction Time and the Triton x-100/Cyclohexane/Methanol/H2O Ratio on the Morphology and Size of Silica Nanoparticles Synthesized via Sol–Gel Assisted by Reverse Micelle Microemulsion. Journal of Materials Science 2014, 49, 3400-3406.
45. Wu, W.-C.; Tracy, J. B., Large-Scale Silica Overcoating of Gold Nanorods with Tunable Shell Thicknesses. Chemistry of Materials 2015, 27, 2888-2894.
46. Bai, Y.; Li, Z.; Cheng, B.; Zhang, M.; Su, K., Higher UV-Shielding Ability and Lower Photocatalytic Activity of TiO2@SiO2/APTES and its Excellent Performance in Enhancing the Photostability of Poly(p-phenylene sulfide). RSC Advances 2017, 7, 21758-21767.
47. Ahmed, M.; Torati, S.; Lee, C.; Rinaldi, C.; Kim, C., Fe3O4/SiO2 Core/Shell Nanocubes: Novel Coating Approach with Tunable Silica Thickness and Enhancement in Stability and Biocompatibility. Journal of Nanomedicine & Nanotechnology 2014, 05.
48. Sharma, R. K.; Sharma, S., Silica Nanosphere-Supported Palladium(ii) Furfural Complex as a Highly Efficient and Recyclable Catalyst for Oxidative Amination of Aldehydes. Dalton Transactions 2014, 43, 1292-1304.
49. Boufi, S.; Baklouti, S.; Pagnoux, C.; Baumard, J.-F., Interaction of Cationic and Anionic Polyelectrolyte with SiO2 and Al2O3 Powders. Journal of the European Ceramic Society 2002, 22, 1493-1500.
50. Wang, J.; Zheng, S.; Shao, Y.; Liu, J.; Xu, Z.; Zhu, D., Amino-Functionalized Fe3O4@SiO2 Core–Shell Magnetic Nanomaterial as a Novel Adsorbent for Aqueous Heavy Metals Removal. Journal of Colloid and Interface Science 2010, 349, 293-299.
51. Aslan, K.; Wu, M.; Lakowicz, J. R.; Geddes, C. D., Fluorescent Core−Shell Ag@SiO2 Nanocomposites for Metal-Enhanced Fluorescence and Single Nanoparticle Sensing Platforms. Journal of the American Chemical Society 2007, 129, 1524-1525.
52. Liu, S.; Han, M.-Y., Silica-Coated Metal Nanoparticles. Chemistry – An Asian Journal 2010, 5, 36-45.
53. Sugawa, K.; Tamura, T.; Tahara, H.; Yamaguchi, D.; Akiyama, T.; Otsuki, J.; Kusaka, Y.; Fukuda, N.; Ushijima, H., Metal-Enhanced Fluorescence Platforms Based on Plasmonic Ordered Copper Arrays: Wavelength Dependence of Quenching and Enhancement Effects. ACS Nano 2013, 7, 9997-10010.
54. Chowdhury, S.; Bhethanabotla, V. R.; Sen, R., Quenching of Fluorescence from CdSe/ZnS Nanocrystal QDs Near Copper Nanoparticles in Aqueous Solution. Plasmonics 2011, 6, 735.
55. Chowdhury, S.; Bhethanabotla, V. R.; Sen, R., Effect of Ag−Cu Alloy Nanoparticle Composition on Luminescence Enhancement/Quenching. The Journal of Physical Chemistry C 2009, 113, 13016-13022.