本研究主要探討水氣與氧氣對膠體量子點(鋅鎘硫硒合金─硫化鋅)光穩定性之影響以及量子點之光氧化機制，量子點在光激發狀態下置於水氣及氧氣環境中皆有發光效率下降的情況，氧氣在照光前期即造成量子點效率的快速衰退，水氣則是在照光初期會先使量子點效率微幅上升才開始衰退，在水氧同時存在的情況下則會加速量子點的劣化。藉由電子能譜儀分析，量子點的表面被證明部分氧化成硫酸鹽類產物，量子點發光效率的下降主要是來自表面氧化過程造成的缺陷增加及表面破壞，使量子點內部激子的放光再結合機率下降。結合量子點暗室穩定性實驗結果與氧化反應之熱力學計算，量子點的光氧化機制主要是由於照光過程中產生的活性氧化物質造成。在發光二極體的應用中，藉由環氧樹脂封裝阻擋水氧的擴散，能夠使量子點的光穩定性得到提升。

In this study, we investigate environmental influence on the photo-stability of ZnCdSeS-ZnS colloidal quantum dots (QDs) with the photo-excitation of blue LED. The phenomenon photo-brightening of QDs is observed in inert environment; whereas, the photoluminescence intensity decrease in oxygen and moisture environment. The decline of QDs efficiency in oxygen and moisture environment is caused by photo-oxidation of QDs, which induces defects formation and QDs surface damage. ZnSO4 and ZnO/Zn(OH)2 are confirmed to be the major oxidation products of the surface ZnS layer of QDs. The dark stability results and theoretical thermodynamics calculations suggest that the surface oxidation of QDs is caused by reactive oxygen species (ROS). Finally, QD LED is fabricated with epoxy resins and the photo-stability is improved due to the protection of epoxy resins from the oxygen/water etching of QDs surface.

中文摘要 i
Abstract ii
誌謝 iii
Contents iv
Chapter 1 Introduction 1
Chapter 2 Literature Review 3
2.1 Introduction of quantum dots – quantum confinement effect 3
2.2 Radiative and non-radiative recombination path of excitons in quantum dots 7
2.3 Photo-stability of QDs 9
2.3.1 Influence of water 9
2.3.2 Influence of oxygen 15
2.3.3 Influence of structure of QDs 17
2.3.4 Influence of ligands on the QDs surface 21
2.3.5 Influence of pH value of QD solution 23
2.3.6 Influence of photo-induced ionization 25
Chapter 3 Experimental Methods 27
3.1 Fabrication of QD film 27
3.2 Fabrication of QD LED 29
3.3 The controlled atmosphere system for QDs illumination experiment 30
3.4 Instruments 32
3.4.1 Optical characterization 32
3.4.2 X-ray photoelectron spectrometer (XPS) 34
3.4.3 High resolution transmission electron microscope (TEM) 34
3.4.4 Fourier transform infrared spectrometer (FTIR) 35
3.4.5 Electrostatic force microscope (EFM) 35
Chapter 4 Results and Discussion 36
4.1 Influence of optical properties of ZnCdSeS-ZnS quantum dots after illumination in various atmospheres 36
4.2 Effect of illumination on the surface composition of quantum dots in various atmospheres 44
4.3 Proposed mechanisms of photo-brightening effect of quantum dots under blue LED illumination in inert atmosphere 54
4.4 Proposed mechanisms of degradation of quantum dots under blue LED illumination in oxygen and/or moisture atmospheres 56
4.5 Performance and photo-stability of quantum dots in LED applications 69
4.6 Photo-stability of quantum dots with smaller size in various atmospheres and LED applications 71
Chapter 5 Conclusions 74
Appendix 75
Appendix 1. Photoluminescence and UV-vis absorption spectrum of ZnCdSeS-ZnS QD solution and QD film 75
Appendix 2. Photo and thermal stability of thin/thick shell ZnCdSeS-ZnS QDs 76
Appendix 3. Photo-stability of ZnCdSeS-ZnS QD LED in air and in vacuum 77
Appendix 4. Ionization of QDs illuminated in dry N2 atmosphere 78
Appendix 5. Lattice plane distance and FFT analysis of QDs illuminated in wet O2 79
References 80

1 C. B. Murray, D. J. Norris and M. G. Bawendi, J. Am. Chem. Soc., 1993, 115, 8706-8715.
2 C. B. Murray, C. R. Kagan and M. G. Bawendi, Annu. Rev. Mater. Sci., 2000, 30, 545–610.
3 J. E. B. Katari, V. L. Colvin and A. P. Alivisatos, J. Phys. Chem., 1994, 98, 4109-4117.
4 M. A. Hines and P. Guyot-Sionnest, J. Phys. Chem., 1996, 100, 468-471.
5 B. O. Dabbousi, J. Rodriguez-Viejo, F. V. Mikulec, J. R. Heine, H. Mattoussi, R. Ober, K. F. Jensen and M. G. Bawendi, J. Phys. Chem. B, 1997, 101, 9463-9475.
6 X. Peng, M. C. Schlamp, A. V. Kadavanich and A. P. Alivisatos, J. Am. Chem. Soc., 1997, 119, 7019-7029.
7 J. J. Li, Y. A. Wang, W. Guo, J. C. Keay, T. D. Mishima, M. B. Johnson and X. Peng, J. Am. Chem. Soc., 2003, 125, 12567-12575.
8 Chen, J. Zhao, V. P. Chauhan, J. Cui, C. Wong, D. K. Harris, H. Wei, H.S. Han, D. Fukumura, R. K. Jain and M. G. Bawendi, Nat. Mater., 2013, 12, 445-451.
9 H. Yang and P. H. Holloway, Adv. Funct. Mater., 2004, 14, 152-156.
10 D. Chen, F. Zhao, H. Qi, M. Rutherford and X. Peng, Chem. Mater., 2010, 22, 1437-1444.
11 L. Li and P. Reiss, J. Am. Chem. Soc., 2008, 130, 11588–11589.
12 M. C. Mancini, B. A. Kairdolf, A. M. Smith and S. Nie, J. Am. Chem. Soc., 2008, 130, 10836–10837.
13 H. Zhao, M. Chaker, N. Wu and D. Ma, J. Mater. Chem., 2011, 21, 8898.
14 D. C. J. Neo, C. Cheng, S. D. Stranks, S. M. Fairclough, J. S. Kim, A. I. Kirkland, J. M. Smith, H. J. Snaith, H. E. Assender and A. A. R. Watt, Chem. Mater., 2014, 26, 4004-4013.
15 M. Regulacio and M. Han, Acc. Chem. Res., 2010, 45, 621-630.
16 K. Boldt, N. Kirkwood, G. A. Beane and P. Mulvaney, Chem. Mater., 2013, 25, 4731-4738.
17 Y. Yang, Y. Zheng, W. Cao, A. Titov, J. Hyvonen, J. R. Manders, J. Xue, P. H. Holloway and L. Qian, Nat. Photonics, 2015, 9, 259-266.
18 B. Mahler, P. Spinicelli, S. Buil, X. Quelin, J. P. Hermier and B. Dubertret, Nat. Mater., 2008, 7, 659-664.
19 Y. Ghosh, B. D. Mangum, J. L. Casson, D. J. Williams, H. Htoon and J. A. Hollingsworth, J. Am. Chem. Soc., 2012, 134, 9634-9643.
20 B. N. Pal, Y. Ghosh, S. Brovelli, R. Laocharoensuk, V. I. Klimov, J. A. Hollingsworth and H. Htoon, Nano Lett., 2012, 12, 331-336.
21 B. Xie, R. Hu and X. Luo, J. Electron. Packag., 2016, 138, 020803.
22 A. Y. Nazzal, X. Wang, L. Qu, W. Yu, Y. Wang, X. Peng and M. Xiao, J. Phys. Chem. B, 2004, 108, 5507-5515.
23 K. Pechstedt, T. Whittle, J. Baumberg and T. Melvin, J. Phys. Chem. C, 2010, 114, 12069–12077.
24 L. Liu, Q. Peng and Y. Li, Inorg. Chem., 2008, 47, 3182-3187.
25 E. Cho, H. Jang, S. Jun, H. A. Kang, J. G. Chung and E. Jang, J. Phys. Chem. C, 2012, 116, 11792-11796.
26 V. I. Klimov, J. Phys. Chem. B, 2006, 110, 16827-16845.
27 F. T. Rabouw and C. de Mello Donega, Top. Curr. Chem., 2016, 374, 58.
28 J. Jasieniak, M. Califano and S. E. Watkins, ACS Nano, 2011, 5, 5888-5902.
29 P. Reiss, M. Protiere and L. Li, Small, 2009, 5, 154-168.
30 I. L. Medintz, H. T. Uyeda, E. R. Goldman and H. Mattoussi, Nat. Mater., 2005, 4, 435-446.
31 X. Zhong, M. Han, Z. Dong, T. J. White and W. Knoll, J. Am. Chem. Soc., 2003, 125, 8589-8594.
32 T. H. Gfroerer, Encyclopedia of Analytical Chemistry, 2006, DOI: 10.1002/9780470027318.a2510.
33 R. Vaxenburg, A. Rodina, A. Shabaev, E. Lifshitz and A. L. Efros, Nano Lett., 2015, 15, 2092-2098.
34 A. L. Efros and M. Rosen, Phys. Rev. Lett., 1997, 78, 1110-1113.
35 C. Galland, Y. Ghosh, A. Steinbruck, M. Sykora, J. A. Hollingsworth, V. I. Klimov and H. Htoon, Nature, 2011, 479, 203-207.
36 S. T. Malak, Y. J. Yoon, M. J. Smith, C. H. Lin, J. Jung, Z. Lin and V. V. Tsukruk, ACS Photonics, 2017, 4, 1691-1704.
37 A. A. Bol and A. Meijerink, J. Phys. Chem. B, 2001, 105, 10203-10209.
38 S. R. Cordero, P. J. Carson, R. A. Estabrook, G. F. Strouse and S. K. Buratt, J. Phys. Chem. B, 2000, 104, 12137-12142.
39 C. Carrillo-Carrion, S. Cardenas, B. M. Simonet and M. Valcarcel, Chem. Commun., 2009, 5214-5226.
40 M. Jones, J. Nedeljkovic, R. J. Ellingson, A. J. Nozik and G. Rumbles, J. Phys. Chem. B, 2003, 107, 11346-11352.
41 W. G. J. H. M. v. Sark, P. L. T. M. Frederix, D. J. V. d. Heuvel and H. C. Gerritsen, J. Phys. Chem. B, 2001, 105, 8281-8284.
42 M. Sykora, A. Y. Koposov, J. A. McGuire, J. M. Pietryga and V. I. Klimov, ACS Nano, 2010, 4, 2021–2034.
43 C. F. Wang, F. Fan, R. P. Sabatini, O. Voznyy, K. Bicanic, X. Li, D. P. Sellan, M. Saravanapavanantham, N. Hossain, K. Chen, S. Hoogland and E. H. Sargent, Chem. Mater., 2017, 29, 5104-5112.
44 C. Y. Cheng and M. H. Mao, J. Appl. Phys., 2016, 120, 083103.
45 Y. Wang, Z. Tang, M. A. C. Duarte, I. P. Santos, M. Giersig, N. A. Kotov and L. M. L. Marza, J. Phys. Chem. B, 2004, 108, 15461-15469.
46 H. Yang, P. H. Holloway, G. Cunningham and K. S. Schanze, J. Chem. Phys., 2004, 121, 10233-10240.
47 G. W. Shu, W. Z. Lee, I. J. Shu, J. L. Shen, J. C. A. Lin, W. H. Chang, R. C. Ruaan and W. C. Chou, IEEE Trans. Nanotechnol, 2005, 4, 632-636.
48 J. Ma, J. Y. Chen, J. Guo, C. C. Wang, W. L. Yang, L. Xu and P. N. Wang, Nanotechnology, 2006, 17, 2083-2089.
49 J. Ma, J. Y. Chen, Y. Zhang, P. N. Wang, J. Guo, W. L. Yang and C. C. Wang, J. Phys. Chem. B, 2007, 111, 12012-12016.
50 K. Sato, S. Kojima, S. Hattori, T. Chiba, K. Ueda-Sarson, T. Torimoto, Y. Tachibana and S. Kuwabata, Nanotechnology, 2007, 18, 465702.
51 H. Asami, Y. Abe, T. Ohtsu, I. Kamiya and M. Hara, J. Phys. Chem. B, 2003, 107, 12566-12568.
52 H. Bao, Y. Gong, Z. Li and M. Gao, Chem. Mater., 2004, 16, 3853-3859.
53 T. D. Krauss and L. E. Brus, Phys. Rev. Lett., 1999, 83, 4840-4843.
54 O. Cherniavskaya, L. Chen, M. A. Islam and L. Brus, Nano. Lett., 2003, 3, 497-501.
55 S. Li, M. L, Steigerwald and L. E. Brus, ACS Nano, 2009, 3, 1267–1273.
56 S. Maenosono, C. D. Dushkin, S. Saita and Y. Yamaguchi, Jpn. J. Appl. Phys., 2000, 39, 4006–4012.
57 S. Maenosono, Chem. Phys. Lett., 2003, 376, 666-670.
58 D. B. Tice, M. T. Frederick, R. P. H. Chang and E. A. Weiss, J. Phys. Chem. C, 2011, 115, 3654-3662.
59 P. Ramasamy, N. Kim, Y. S. Kang, O. Ramirez and J. S. Lee, Chem. Mater., 2017, 29, 6893-6899.
60 L. S. Dake, D. R. Baer and J. M. Zachara, Surf. Interface Anal., 1989, 14, 71-75.
61 E. Agostinelli, C. Battistoni, D. Fiorani, G. Mattogno and M. Nogues, J. Phys. Chem. Solids, 1989, 50, 269-272.
62 W. E. S. Jr., K. J. Wynne and D. M. Hercules, Anal. Chem., 1971, 43, 1884-1887.
63 R. V. Siriwardane and J. A. Poston, Appl. Surf. Sci., 1990, 45, 131-139.
64 G. Deroubaix and P. Marcus, Surf. Interface Anal., 1992, 18, 39-46.
65 M. I. De Barros, J. Bouchet, I. Raoult, T. Le Mogne, J. M. Martin, M. Kasrai and Y. Yamada, Wear, 2003, 254, 863-870.
66 V. I. Nefedov, J. Electron Spectrosc. Relat. Phenom., 1982, 25, 29-47.
67 C. Battistoni, J. L. Dormann, D. Fiorani, E. Paparazzo and S. Viticoli, Solid State Comm., 1981, 39, 581-585.
68 H. Peisert, T. ChassB, P. Streubel, A. Meisel and R. Szargan, J. Electron Spectrosc. Relat. Phenom., 1994, 68, 321-328.
69 S. S. M Shenasa, D Lichtman, J. Electron. Spectrosc. Relat. Phenom., 1986, 40, 329-337.
70 D. L. Pavia, G. M. Lampman, G. S. Kriz and J. A. Vyvyan, Introduction to spectroscopy, Cengage, Boston, 2008.
71 D. Dwibedi, R. B. Araujo, S. Chakraborty, P. P. Shanbogh, N. G. Sundaram, R. Ahuja and P. Barpanda, J. Mater. Chem. A, 2015, 3, 18564-18571.
72 D. D. Wagman, W. H. Evans, V. B. Parker, R. H. Schumm and I. Halow, J. Phys. Chem. Ref. Data, Suppl., 1982, 11.
73 W. H. Koppenol and J. Butler, Adv. Free Radical Biol. Med., 1985, 1, 91-131.
74 A. Fujishima, X. Zhang and D. Tryk, Surf. Sci. Rep., 2008, 63, 515-582.
75 F. Wei, L. Ni and P. Cui, J. Hazard. Mater., 2008, 156, 135-140.
76 W. Xie, Y. Li, W. Sun, J. Huang, H. Xie and X. Zhao, J. Photochem. Photobiol., A, 2010, 216, 149-155.
77 C. Tian, Q. Zhang, A. Wu, M. Jiang, Z. Liang, B. Jiang and H. Fu, Chem. Commun., 2012, 48, 2858-2860.
78 D. Chen, F. Huang, G. Ren, D. Li, M. Zheng, Y. Wang and Z. Lin, Nanoscale, 2010, 2, 2062-2064.
79 C. J. Chang, K. L. Huang, J. K. Chen, K. W. Chu and M. H. Hsu, J. Taiwan Inst. Chem. Eng., 2015, 55, 82-89.
80 W. Ho and J. C. Yu, J. Mol. Catal. A: Chem., 2006, 247, 268-274.
81 J. Zhao, M. A. Holmes and F. E. Osterloh, ACS Nano, 2013, 7, 4316–4325
82 M. A. Holmes, T. K. Townsend and F. E. Osterloh, Chem. Commun., 2012, 48, 371-373.
83 J. C. Colmenares and R. Luque, Chem. Soc. Rev., 2014, 43, 765-778.
84 A. H. Mamaghani, F. Haghighat and C. S. Lee, Appl. Catal., B, 2017, 203, 247-269.
85 J. Brandrup, E. H. Immergut, E. A. Grulke, A. Abe and D. R. Bloch, Polymer handbook, Wiley-Interscience, Hoboken, 1999.
86 A. I. H. Committee, Engineered materials handbook: adhesives and sealants, CRC Press, Boca Raton, 1990.
87 L. K. Massey, Permeability properties of plastics and elastomers: a guide to packaging and barrier materials, William Andrew, Norwich, 2003.