臺灣博碩士論文加值系統

CdS and ZnS core nanoparticles were synthesized by microwave method and then coated with shell material by traditional method, using simple and safe reagents such as cadmium acetate, zinc acetate, and thiourea to synthesis the core shell nanopartices. After coating CdS core by ZnS shell the photoluminescence intensity greatly increase from 18 a.u to a maximum photoluminescence intensity of 225 a.u. For ZnS/CdS core shell nanoparticles, after CdS coated on ZnS core, the photoluminescence intensity increases significantly too, the bare ZnS cores have a photoluminescence intensity of 353 a.u and the ZnS/CdS core shell nanoparticles can reach a maximum photoluminescence intensity of 1460 a.u. Shell formation was confirmed by observation of a red shifting in the photoluminescence spectra. As the precursor feeding rate decreases, it leads the formation of bigger core shell nanoparticles, and so does the increases of precursor concentration. The advantage of the process is that it can be carried out in the open air using simple equipment and is simpler, cheaper, and safer as compared with another method.

Abstract ………………………………………………………………… I Acknowledgement……………………………………………………… II
Contents ………………………………………………………………… IV
List of Figures ……………………………………………………….…. VII
List of Tables …………………………………………………………… XIV
Chapter 1 Introduction …………………………………………………. 1
1.1 Motivation and purpose ……………………………………… 1
1.2 Outline ……………………………………………………….. 4
Chapter 2 Literature Review …………………………………………… 7
2.1 Synthesis Nanoparticles through Homogeneous Nucleation … 8
2.2 Synthesis Nanoparticles through Heterogeneous Nucleation ... 11
2.3 The Photoelectric Effect ……………………………………… 13
2.4 Energy Bands ………………………………………………… 15
2.5 Metals, Semiconductors, and Isolators ………………………. 17
2.6 Electrons and Holes ………………………………………….. 18
2.7 Direct and Indirect Semiconductors ………………………….. 19
2.8 Optical Absorption …………………………………………… 20
2.9 Luminescence ………………………………………………… 21
2.9.1 Phosphorescence and Fluorescence ……………………... 22
2.10 Photoluminescence …………………………………………… 23
2.11 Quantum Dots ………………………………………………... 24
2.12 Quantum Confinement ……………………………………….. 27
2.13 Enhance the Quantum Yield …………………………………. 29
2.13.1 Nanoparticle Optimization ……………………………… 29
2.13.2 Second Component ……………………………………… 30
2.13.3 Photoactivation ………………………………………….. 30
2.13.4 Shell Coating ……………………………………………. 31
2.14 Core shell Nanostructure …………………………………….. 32
2.14.1 Type I Quantum Dots …………………………………… 33
2.14.2 Type II Quantum Dots …………………………………... 33
2.15 Lattice constant calculation …………………………………... 35
Chapter 3 Materials and Methods ………………………………………. 36
3.1. Chemical and Materials ………………………………………. 36
3.2 Equipment ……………………………………………………. 36
3.3 Methods ………………………………………………………. 37
3.3.1 Synthesis CdS core nanoparticles ……………………….. 37
3.3.2 Coating CdS core with ZnS shell ……………………….. 38
3.3.2.1 Using pre heating ZnS precursor …………………….. 38
3.3.2.2 Without pre heating ZnS precursor ………………….. 38
3.3.3 Synthesis ZnS core nanoparticles ……………………….. 40
3.3.4 Coating ZnS core with CdS shell at 180oC and 200 oC
reaction temperature using various added
precursor rate ……………………………………………. 41
3.4 Analysis Instrument ………………………………………….. 42
3.5 Material Properties …………………………………………… 43
3.5.1 Cadmium acetate ………………………………………... 43
3.5.2 Zinc acetate ……….……………………………………... 43
3.5.3 Thiourea ………..………………………………………...43

3.5.4 TOPO …………………………………..………………... 44
3.5.5 TOP ……………………………….……………………... 44
3.5.6 N, N-Dimethylformamide (DMF) …………………..…... 45
3.5.7 Cadmium Sulfide nanocrystal …....……………………... 45
3.5.8 Zinc Sulfide nanocrystal …………….…………………... 46
Chapter 4 Result and Discussion ……………………………………….. 48
4.1 Synthesis CdS and ZnS nanoparticles ………………………... 48
4.2 Synthesis CdS/ZnS using pre-heating ZnS precursor ………... 49
4.3 Synthesis CdS/ZnS without using pre-heating ZnS precursor... 51
4.3.1 Synthesis CdS/ZnS at 180oC reaction temperature
With various ZnS precursor feeding rates ...…………….. 51
4.3.2 Synthesis CdS/ZnS at 180oC reaction temperature
With various ZnS concentrations ……...……………….. 57
4.3.3 Synthesis CdS/ZnS at 200oC reaction temperature
With various ZnS precursor feeding rates …..………….. 63
4.3.4 Synthesis CdS/ZnS at 200oC reaction temperature
With various ZnS concentrations ……………………….. 69
4.4 Synthesis of ZnS/CdS core shell nanoparticles ………………. 75
4.4.1 Synthesis ZnS/CdS at 180oC reaction temperature
With various CdS precursor feeding rate ……………….. 75
4.4.1 Synthesis ZnS/CdS at 200oC reaction temperature
With various CdS precursor feeding rates……………….. 81
Chapter 5 Conclusion …………………………………………………... 88
References ……………………………………………………………… 90

[1]G.Y. Tseng, J.C. Ellenbogen, Science 294, (2001) 1293
[2]G.Z. Cao, Nanosrtuctures and Nanomaterials Synthesis, Properties and Applications, Imperial College Press (2004)
[3]J.H. Schon, H. Meng, Z. Bao, Science 294, (2001) 2138
[4]Aviram, M.A. Ratner, Chem. Phys. Lett. 29, 277 (1974)
[5]J.H. Schon, H. Meng, Z. Bao, Nature 413, (2001) 713
[6]K.Guido, Hybrid Materials. Synthesis, Characterization, and Applications, 2007
[7]J.R. Ireland, J. McMath, J. Ramsley, Insights in Nanomedicine : Fight Cancer with Gold Nanoshells, NanoEd Resource Portal, 2004
[8]Y.C. Tian, T. Newton, N.A. Kotov, D.M. Guldi, J.H. Fendler, J. Phys. Chem. 21, 100 (1996) 8927–8939
[9]Y. Wang, Z.Y. Tang, M.A. Correa-Duarte, I.P. Santos, M. Giersig, N.A. Kotov, L.M. Liz-Marzan, J. Phys. Chem. B, 108 (2004) 15461-15469
[10]A.R. Loukanov, C.D. Dushkin, K.I. Papazova, A.V. Kirov, M.V. Abrashev, E. Adachi, Colloide Surf. A, 245(2004) 9-14
[11]M. Protiere, P. Reiss, Nanoscale Res. Lett., 1(2006) 62-67
[12]M. Ethayaraja, C. Ravikumar, D. Muthukumar, K. Dutta, R. Bandyopadhayaya, J. Phys. Chem. C, 111 (2007) 3246-3252
[13]R.S. Mane, C.D. lokhande, Mater. Chem. Phys., 65 (2000) 1
[14]G. Henshaw, I.P Oarkin, G. Shaw, Chem. Commun., (1996) 1095
[15]R. He, X.F. Qian, J. Yin, H.A. Xi, L.J. Bian, Z.K. Zhu, Colloide Surf. A, 220 (2003) 151-157
[16]Datta, S.K. Panda, S. Chaudhuri, J. Phys. Chem. C, 111 (2007) 17260-17264
[17]J.W. Kemling, Advances in Lasing from Colloidal Quantum Dots, 2007
[18]X.H. Zhong, R.G. Xie, Y. Zhang, T. Basche, W. Knoll, Chem. Mater., 17 (2005) 4038-4042
[19]D. Yang, Q. Chen, S. Xu, J. of Luminescence, 126 (2007) 853-85
[20]W. Shockley, Electron and Holes in Semiconductors, Litton Educational Publishing Co., Inc., 1950
[21]W. Middleton, M.E. Van Valkenburg, Reference Data for Engineers, 9th ed, 2002
[22]R. Lakowicz, Principles of Fluorescence Spectroscopy, 2nd ed., New York 1999
[23]Skoog, F. J. Holler, T. A. Nieman, Principles of Instrumental Analysis, 5th ed., 1998
[24]K.M. Yeh, The Synthesis and Optoelectronic Properties of Electroluminescent and Phosphorescent Host Polymers, Doctoral Dissertation, National Cheng Kung University, 2007
[25]B.G. Streetman, Solid State Electronic Devices, 2nd ed., Prentice Hall (1980)
[26]S.M. Sze, Physics of Semiconductor Device, Wiley Interscience Publication, New York, 1981
[27]B.O. Dabbousi, J. Rodriguez-Viejo, F.V. Mikulec, J.R. Heine, H. Mattoussi, R. Ober, K.F. Jensen, M.G. Bawendi, J. Phys. Chem. B, 101 (1997) 9463-9475
[28]L.A. Peyser, A.E. Vinson, A.P. Bartko, R.M. Dickson, Science Mag. 291, 5501 (2001) 103-106
[29]B. Murray, D.J. Norris, M.G. Bawendi, J. Am. Chem. Soc., 115 (1993) 8706
[30]T. Vossmeyer, L. Katsikas, M. Giersig, I.G. Popovic, K. Diesner, A. Chemseddine, A. Eyechmuller, H. Weller, J. Phys. Chem., 98 (1994) 7665
[31]Z.A. Peng, X. Peng, J. Am. Chem. Soc., 123 (2001) 183
[32]A.L. Smith, Particle Growth in Suspension, AcademicPress : London, 1983, 3-15
[33]C.B. Murray, D.J. Norris, M.G. Bawendi, J. Am. Chem. Soc., 115 (1993) 8706-8715
[34]A.A. Bol, A. Meijerink, J. Phys. Chem. B, 105 (2001) 10197
[35]Y. Wang, Z. Tang, M.A. Correa-Duarte, L.M. Liz-Marzan, N.A. Kotov, J. Am. Chem. Soc., 125 (2003) 283
[36]A.A. Bol, A. Meijerink, J. Phys. Chem. B, 105 (2001) 10203
[37]L.A. Peyser, A.E. Vinson, A.P. Bartko, R.M. Dickson, Science Mag. 291, 5501 (2001) 103-106
[38]M.A. Malik, P. O’Brien, N. Revaprasadu, Chem. Mater., 14 (2002) 2004-2010
[39]R. Xie, U. Kolb, J.X. Li, T. Basche, A. Mews, J. Am. Chem. Soc., 127 (2005) 7480-7488
[40]S.A. Ivanov, A. Piryatinski, J. Nanda, S, Tretiak, K.R. Zavaldi, W.O. Wallace, D. Werder, V.I. Klimov, J. Am. Chem. Soc., 129 (2007) 11708-11719
[41]Nemchinov, M. Kirsanova, N.N. Hewa-Kasakarage, M. Zamkov, J. Phys. Chem. C, 112 (2008) 9301-9307
[42]R. Hua, J.H. Niu, M.T. Li, T.Z. Yu, W.L. Li, Chem. Phys. Lett., 419 (2006) 269-272
[43]K. Rajeshwar, N.R. TAcconi, C.R. Chenthamarakshan, Chem. Mater., 13 (2001) 27
[44]S. Kalele, S.W. Gosavi, J. Urban, S.K. Kulkarni, Curr. Sci., 91 (2006) 103
[45]R.G. Xie, U. Kolb, J.X. Li, T. Basche, A. Mews, J. Am. Chem. Soc., 127 (2005) 7480
[46]J.P. Schaffer, A. Saxena, S.D. Antolovich, T.H. Sanders,Jr., S.B. Warner, The Science and Design of Engineering Materials, 2nd ed, McGraw-Hill, 1999