ZnO can be made into many nanostructures that have unique properties for advanced applications, such as piezoelectric and pyroelectric materials. ZnOnanorod is one of the nanostructures that possess advanced properties. This paper reports a gas phase flame process to continuously synthesize aerosols of ZnOnanorods in large quantities. Unlike previous work, our process shows that pure ZnOnanorods can be made in a freestanding form rather than growing on a substrate surface. It was found that the ZnOnanorods preferentially grow in the thermodynamically stable direction [001] in the gas phase with different aspect ratios, depending on flame process conditions. The ZnOnanorod aerosols are highly crystalline and have a hexagonal geometry. Raman and photoluminescence spectroscopic studies showed that there are no structural defects in the nanorods, which have energy band gap of 3.27 eV in the near UV region. It was demonstrated that the gas phase flame reactor can provide a convenient means for continuous production of highly pure aerosols of ZnOnanorods.
References
[1]
Z. L. Wang, “Zinc Oxide Nanostructures: Growth, Properties and Applications,” Journal of Physics Condensed Matter, Vol. 16, No. 25, 2004, pp. R829-R858. http://dx.doi.org/10.1088/0953-8984/16/25/R01
[2]
S. Sakthivela, B. Neppolianb, M. V. Shankarb, B. Arabindoob, M. Palanichamy and V. Murugesan, “Solar Photocatalytic Degradation of Azo Dye: Comparison of Photocatalytic Efficiency of ZnO and TiO2,” Solar Energy Materials and Solar Cells, Vol. 77, No. 1, 2003, pp. 6582. http://dx.doi.org/10.1016/S0927-0248(02)00255-6
[3]
Y. Hao, M. Yang, W. Li, X. Qiao, L. Zhang and S. Cai, “A Photoelectrochemical Solar Cell Based on ZnO/Dye/ polypyrrole Film Electrode as Photoanode,” Solar Energy Materials and Solar Cells, Vol. 60, No. 4, 2000, pp. 349-354. http://dx.doi.org/10.1016/S0927-0248(99)00053-7
[4]
R. Jose, V. Thavasi and S. Ramakrishna, “Metal Oxides for Dye-Sensitized Solar Cells,” Journal of American Ceramic Society, Vol. 92, No. 2, 2009, pp. 289-301. http://dx.doi.org/10.1016/j.ssc.2003.11.051
[5]
X. C. Sun, H. Z. Zhang, J. Xu, Q. Zhao, R. M. Wang and D. P. Yu, “Shape Controllable Synthesis of ZnO Nanorod Arrays via Vapor Phase Growth,” Solid State Communications, Vol. 129, No. 12, 2004, pp. 803-807. http://dx.doi.org/10.1016/j.ssc.2003.11.051
[6]
X. Y. Kong, Y. Ding, R. Yang and Z. L. Wang, “SingleCrystal Nanorings Formed by Epitaxial Self-Coiling of Polar Nanobelts,” Science, Vol. 303, No. 5662, 2004, pp. 1348-1351. http://dx.doi.org/10.1126/science.1092356
[7]
N. Tamaekong, C. Liewhiran, A. Wisitsoraat and S. Phanichphant, “Flame Spray-Made Undoped Zinc Oxide Films for Gas Sensing Applications,” Sensor, Vol. 10, No. 8, 2010, pp. 7863-7873. http://dx.doi.org/10.3390/s100807863
[8]
M. J. Height, L. Madler and S. E. Pratsinis, “Nanorods of ZnO Made by Flame Spray Pyrolysis,” Chemistry of Materials, Vol. 18, No. 2, 2006, pp. 572-578. http://dx.doi.org/10.1021/cm052163y
[9]
A. B. Hartanto, X. Ning, Y. Nakata and T. Okada, “Growth Mechanism of ZnO Nanorods from Nanoparticles Formed in a Laser Ablation Plume,” Applied Physics A, Vol. 78, No. 3, 2004, pp. 299-301. http://dx.doi.org/10.1007/s00339-003-2286-2
[10]
W. I. Park, D. H. Kim, S. W. Jung and G. C. Yi, “Metalorganic Vapor-Phase Epitaxial Growth of Vertically Well-Aligned ZnO Nanorods,” Applied Physics Letters, Vol. 80, No. 22, 2002, pp. 4232-4234. http://dx.doi.org/10.1063/1.1482800
[11]
J. J. Wu and S. C. Liu, “Low-Temperature Growth of Well-Aligned ZnO Nanorods by Chemical Vapor Deposition,” Advanced Materials, Vol. 14, 2002, pp. 215-218.
[12]
F. Xu, C. D’Esposito, X. Liu, B. Kear and S. D. Tse, “Flame Synthesis of ZnON Anostrucutres: Morphology and Local Growth Conditions,” Materials Research Society Symposium Proceedings, Vol. 1142, 2009, pp. JJ05JJ39.
[13]
Y. C. Hong, J. H. Kim and H. S. Uhm, “ZnO Nanorods Synthesized by Self-Catalytic Method of Metal in Atmospheric Microwave Plasma Torch Flame,” Japanese Journal of Applied Physics, Vol. 45, No. 7, 2006, pp. 5940-5944. http://dx.doi.org/10.1143/JJAP.45.5940
[14]
H. Peng, Y. Fangli, B. Liuyang, L. Jinlin and C. Yunfa, “Plasma Synthesis of Large Quantities of Zinc Oxide Nanorods,” Journal of Physical Chemistry C, Vol. 111, No. 1, 2007, pp. 194-200. http://dx.doi.org/10.1021/jp065390b
[15]
M. K. Akhtar, S. E. Pratsinis and S. V. R. Mastrangelo, “Dopants in Vapor-Phase Synthesis of Titania Powders,” Journal of American Ceramic Society, Vol. 75, No. 12, 1992, pp. 3408-3416. http://dx.doi.org/10.1111/j.1151-2916.1992.tb04442.x
[16]
T. Tani, L. Madler and S. E. Pratsinis, “Homogeneous ZnO Nanoparticles by Flame Spray Pyrolysis,” Journal of Nanoparticle Research, Vol. 4, No. 4, 2002, pp. 337-343. http://dx.doi.org/10.1023/A:1021153419671
[17]
F. Xu, S. D. Tse, J. F. Al-Sharab and B. H. Kear, “Flame Synthesis of Aligned Tungsten Oxide Nanowires,” Applied Physics Letters, Vol. 88, 2006, Article ID: 243115. http://dx.doi.org/10.1063/1.2213181
[18]
P. M. Rao and X. Zheng, “Rapid Catalyst-Free Flame Synthesis of Dense, Aligned-Fe2O3 Nanoflake and Cuonanoneedle Arrays,” Nano Letters, Vol. 9, No. 8, 2009, pp. 3001-3006. http://dx.doi.org/10.1021/nl901426t
[19]
W. Merchan-Merchan, A. V. Saveliev and A. M. Taylor, “High Rate Flame Synthesis of Highly Crystalline Iron Oxide Nanorods,” Nanotechnology, Vol. 19, 2008, Article ID: 125605. http://dx.doi.org/10.1088/0957-4484/19/12/125605
[20]
W. Merchan-Merchan, A. V. Saveliev and V. Nguyen, “Opposed Flow Oxy-Flame Synthesis of Carbon and Oxide Nanostrucutres on Molybdenum Probes,” Proceedings of the Combustion Institute, Vol. 32, No. 2, 2009, pp. 1879-1886. http://dx.doi.org/10.1016/j.proci.2008.07.025
[21]
S. L. Chung and J. L. Katz, “The Counterflow Diffusion Flame Burner: A New Tool for the Study of the Nucleation of Refractory Compounds,” Combustion and Flame, Vol. 61, No. 3, 1985, pp. 271-279. http://dx.doi.org/10.1016/0010-2180(85)90108-7
[22]
Y. Xing, U. O. Koylu and D. E. Rosner, “Synthesis and Restructuring of Inorganic Nanoparticles in Counterflow diffusion Flames,” Combustion and Flame, Vol. 107, No. 1996, pp. 85-102. http://dx.doi.org/10.1016/0010-2180(96)00005-3
[23]
Y. Xing, T. P. Kole and J. L. Katz, “Shape Controlled Synthesis of Iron Oxide Nanoparticles,” Journal of Materials Science Letters, Vol. 22, No. 11, 2003, pp. 787-790. http://dx.doi.org/10.1023/A:1023923104337
[24]
G. C. Yi, C. Wang and W. I. Park, “ZnO Nanorods: Synthesis, Characterization and Applications,” Semiconductor Science and Technology, Vol. 20, No. 4, 2005, pp. S22-S34. http://dx.doi.org/10.1088/0268-1242/20/4/003
[25]
M. R. Zachariah, D. Chin, H. G. Semerjian and J. L. Katz, “Silica Particle Synthesis in a Counterflow Diffusion Flame Reactor,” Combustion and Flame, Vol. 78, No. 3-4, 1989, pp. 287-298. http://dx.doi.org/10.1016/0010-2180(89)90018-7
[26]
I. S. Altman, I. E. Agranovski and M. Choi, “Nanoparticle Generation: The Concept of a Stagnation Size Region for Condensation Growth,” Physical Review E, Vol. 70, 2004, Article ID: 062603. http://dx.doi.org/10.1103/PhysRevE.70.062603
[27]
T. P. Pandya and F. J. Weinberg, “The Structure of Flat Counterflow Diffusion Flames,” Proceedings of the Royal Society London, Series A: Mathematical and Physical Sciences, Vol. 279, No. 1379, 1964, pp. 544-561. http://dx.doi.org/10.1098/rspa.1964.0124
[28]
D. C. Kim, B. H. Kong and H. K. Cho, “Synthesis and Growth Mechanism of Catalyst Free ZnO Nanorods with Enhanced Aspect Ratio by High Flow Additional Carrier Gas at Low Temperature,” Journal of Physics D: Applied Physics, Vol. 42, 2009, Article ID: 065406. http://dx.doi.org/10.1088/0022-3727/42/6/065406
[29]
L. Vayssieres, K. Keis, A. Hagfeldt and S. E. Lindquist, “Three-Dimensional Array of Highly Oriented Crystalline ZnO Microtubes,” Chemistry of Materials, Vol. 13, No. 12, 2001, pp. 4395-4398. http://dx.doi.org/10.1021/cm011160s
[30]
C. Ye, X. Fang, Y. Hao, X. Teng and L. Zhang, “Zinc Oxide Nanostrucutres: Morphology Derivation and Evolution,” Journal of Physical Chemistry B, Vol. 109, No. 42, 2005, pp. 19758-19765. http://dx.doi.org/10.1021/jp0509358
[31]
Y. Kuniya, Y. Deguchi and M. Ichida, “Physicochemical Properties of Dimethylzinc, Dimethylcadmium and Diethylzinc,” Applied Organometallic Chemistry, Vol. 5, No. 4, 1991, pp. 337-347. http://dx.doi.org/10.1002/aoc.590050419
[32]
H. E. Ruiz, “Synthesis of Iron Oxide Nanoparticles in a Counterflow Diffusion Flame Reactor,” M.S. Thesis, Missouri University of Science and Technology, 2008.
[33]
Ph. Buffat and J-P. Borel, “Size Effect on Melting Temperature of Gold Particles,” Physical Review A, Vol. 13, No. 6, 1976, pp. 2287-2298. http://dx.doi.org/10.1103/PhysRevA.13.2287
[34]
J. B. Baxter, F. Wu and E. S. Aydil, “Growth Mechanism and Characterization of Zinc Oxide Hexagonal Columns,” Applied Physics Letters, Vol. 83, No. 18, 2003, pp. 3797-3799. http://dx.doi.org/10.1063/1.1624467
[35]
J. M. Calleja and M. Cardona, “Resonant Raman Scattering in ZnO,” Physical Review B, Vol. 16, No. 8, 1977, pp. 3753-3761. http://dx.doi.org/10.1103/PhysRevB.16.3753
[36]
A. Umar, S. H. Kim, Y. S. Lee, K. S. Nahm and Y. B. Hahn, “Catalyst-Free Large-Quantity Synthesis of ZnONanorods by Vapor-Solid Growth Mechanism: Structural and Optical Properties,” Journal of Crystal Growth, Vol. 282, No. 1-2, 2005, pp. 131-136. http://dx.doi.org/10.1016/j.jcrysgro.2005.04.095
[37]
R. S. Zeferino, M. B. Flores and U. Pal, “Photoluminescence and Raman Scattering in Ag-Doped ZnONanoparticles,” Journal of Applied Physics, Vol. 109, 2011, Article ID: 014308. http://dx.doi.org/10.1063/1.3530631
[38]
H. Zeng, G. Duan, Y. Li, S. Yang, X. Xu and W. Cai, “Blue Luminescence of ZnO Nanoparticles Based on Non-Equilibrium Processes: Defect Origins and Emission Controls,” Advanced Functional Materials, Vol. 20, No. 4, 2010, pp. 561-572. http://dx.doi.org/10.1002/adfm.200901884
[39]
Y. Wang, I. Ramos and J. J. Santiago-Aviles, “Optical Bandgap and Photoconductance of Electrospun Tin Oxide Nanofibers,” Journal of Applied Physics, Vol. 102, 2007, Article ID: 093517. http://dx.doi.org/10.1063/1.2800261
[40]
C. F. Klingshirn, B. K. Meyer, A. Waag, A. Hoffman and J. Geurts, “Zinc Oxide: From Fundamental Properties towards Novel Applications,” Springer, Berlin, 2010. http://dx.doi.org/10.1007/978-3-642-10577-7
