本研究主要是藉由旋塗技術研製一套全濕式製程來製備量子點發光二極體。元件是由多層薄膜逐層沉積而成，因此旋塗轉速及溶劑均會影響薄膜品質，透過階段性旋塗轉速及溶劑的選擇，使得各層薄膜可以均勻沉積於基板上。發光層方面，兩種不同結構的量子點被應用於此研究中，並探討其元件表現，結合電性及光學量測的結果，發現ZnS殼的結構可以阻擋電子並有更好的載子注入匹配，透過量子侷限史塔克效應（QCSE）的實驗，也發現光譜的偏移以及半高寬變寬與載子注入不匹配有關。為進一步提升元件效率，藉由優化傳輸層厚度，以減少漏電流的產生，使其在低電流密度下有更好的表現，最後透過材料參雜工程，提升電洞的注入能力，使載子注入更匹配來提升整體效率，經果此研究，我們成功製備出效率EQE: 10%，且亮度可達280,000尼特之量子點電致發光二極體，期望未來可以應用於顯示器中。

In this study, all-solution process was used via spin-coating technology to fabricate quantum dot light-emitting diodes. The device was composed of thin films deposited layer by layer. Therefore, the spin rate and solvents would affect the quality of thin films a lot. By a step-wise spin rate and selection of suitable solvents, films of each layers could be deposited on substrate uniformly. For emission layer, two structures of quantum dot are adopted in this research, and their performance of QLEDs also are investigated. By analyzing their electrical and optical properties, it is found that ZnS shell plays an important role to balance the carrier injection. From quantum-confined Stark effect, it is observed the effect of imbalance carrier injection on peak redshift and broadening. Eventually, by doping engineering, high performance of QLEDs are successfully fabricated, and their EQE and brightness reached 10% and 280,000 nits, respectively. Hopefully, QLEDs can be applied to displays in the future.

中文摘要------------------------------------------------------------2
Abstract-----------------------------------------------------------3
Contents-----------------------------------------------------------5
Chapter 1 Introduction--------------------------------------------7
Chapter 2 Literature Review---------------------------------------9
2.1 Composition and structure of quantum dot-----------------------9
2.2 Quantum-confined Stark effect---------------------------------13
2.3 Working principles of quantum dot light-emitting diode--------16
2.4 Device Structure of QLED--------------------------------------18
2.4.1 Conventional type QLED--------------------------------------18
2.4.2 Inverted type QLED------------------------------------------18
2.5 Improvement of QLED performance by transport layer modification ------------------------------------------------------------------20
2.5.1 Modification of Electron transport layer--------------------20
2.5.2 Modification of Hole transport layer------------------------26
Chapter 3 Experimental-------------------------------------------31
3.1 Chemicals-----------------------------------------------------31
3.2 Preparation of quantum dot solution---------------------------31
3.3 Device fabrication--------------------------------------------32
3.4 Device measurement--------------------------------------------34
3.5 Instruments---------------------------------------------------35
3.5.1 Device Characterization-------------------------------------35
3.5.2 Scanning Electron Microscope--------------------------------36
3.5.3 Atomic Force Microscope-------------------------------------37
3.5.5 High Resolution Transmission Electron Microscopy------------38
Chapter 4 Results and Discussion---------------------------------39
4.1 Establishment of QLED fabrication-----------------------------39
4.1.1 Hole injection layer with PEDOT:PSS solution----------------39
4.1.3 Solvents of quantum dot for emission layer------------------45
4.2. Electrical and optical characteristics of QLED---------------47
4.3 Optimization of film thickness with carrier transport layer---61
4.4 Improvement of hole injection ability by doping organic material ------------------------------------------------------------------69
4.5 Reproducibility for high brightness quantum dot light-emitting diodes------------------------------------------------------------74
Chapter 5 Conclusions--------------------------------------------76
References--------------------------------------------------------77

[1] C. B. Murray, D. J. Norris and M. G. Bawendi, J. Am. Chem. Soc., 1993, 115, 8706-8715.
[2] V. L. Colvin, M. C. Schlamp and A. P. Alivisatos, Nature, 1994, 370, 354-357.
[3] N. Tessler, V. Medvedev, M. Kazes, S. Kan and U. Banin, Science, 2002, 295, 1506-1508.
[4] D. J. Norris, A. L. Efros, M. Rosen and M. G. Bawendi, Phys. Rev. B, 1996, 53, 16347.
[5] J. Lee, V. C. Sundar, J. R. Heine, M. G. Bawendi and K. F. Jensen, Adv. Mater., 2000, 12, 1102-1105.
[6] S. Mei, X. Liu, W. Zhang, R. Liu, L. Zheng, R. Guo and P. Tian, ACS Appl. Mater. Interfaces, 2018, 10, 5641-5648.
[7] V. L. Colvin, M. C. Schlamp and A. P. Alivisatos, Nature, 1994, 370, 354-357.
[8] Y. Sun, Y. Jiang, X. W. Sun, S. Zhang and S. Chen, Chem. Rec., 2019, 19, 1729-1752.
[9] Y. Zou, Y. Liu, M. Ban, Q. Huang, T. Sun, Q. Zhang and B. Sun, Nanoscale Horiz., 2017, 2, 156-162.
[10] J. Q. Grim, L. Manna and I. Moreels, Chem. Soc. Rev., 2015, 44, 5897-5914.
[11]P. Reiss, M. Protiere and L. Li, Small, 2009, 5, 154-168.
[12] Y. Li, Y. Ding, Y. Zhang and Y. Qian, J. Phys. Chem. Solids, 1999, 60, 13-15.
[13] C. A. Smith, H. W. H. Lee, V. J. Leppert and S. H. Risbud, Appl. Phys. Lett., 1999, 75, 1688-1690.
[14] P. V. Kamat, J. Phys. Chem. C, 2008, 112, 18737-18753.
[15] J. A. Hansen, J. Wang, A. N. Kawde, Y. Xiang, K. V. Gothelf and G. Collins, J. Am. Chem. Soc., 2006, 128, 2228-2229.
[16] M. D. Regulacio and M. Y. Han, Acc. Chem. Res., 2010, 43, 621-630.
[17] M. Grabolle, J. Ziegler, A. Merkulov, T. Nann and U. R. Genger, Ann. N. Y. Acad. Sci., 2018, 1130, 235-241.
[18] H. Shen, Q. Lin, H. Wang, L. Qian, Y. Yang, A. Titov and L. S. Li, ACS Appl. Mater. Interfaces, 2013, 5, 12011-12016.
[19] S. K. Panda, S. G. Hickey, C. Waurisch and A. Eychmüller, J. Mater. Chem., 2011, 21, 11550-11555.
[20] W. K. Bae, K. Char, H. Hur and S. Lee, Chem. Mater., 2008, 20, 531-539.
[21] X. Zhong, M. Han, Z. Dong, T. J. White and W. Knoll, J. Am. Chem. Soc., 2003, 125, 8589-8594.
[22] S. A. Empedocles and M. G. Bawendi, Science, 1997, 278, 2114-2117.
[23] T. Takeuchi, C. Wetzel, S.Yamaguchi, H. Sakai, H. Amano, I. Akasaki and N. Yamada, Appl. Phys. Lett., 1998, 73, 1691-1693.
[24] P. B. Wilkinson, T. M. Fromhold, L. Eaves, F. W. Sheard, N. Miura and T. Takamasu, Nature, 2016, 380, 608-610.
[25] D. Schooss, A. Mews, A. Eychmüller and H. Weller, Phys. Rev. B, 1994, 49, 17072.
[26] H. Moon, C. Lee, W. Lee, J. Kim and H. Chae, Adv. Mater., 2019, 31, 1804294.
[27] J. Verma, S. M. Islam, A. Verma, V. Protasenko and D. Jena, Woodhead Publishing, 2018, 377-413.
[28] D. A. Miller, D. S. Chemla, T. C. Damen, A. C. Gossard, W. Wiegmann, T. H. Wood and C. A. Burrus, Phys. Rev. Lett., 1984, 53, 2173.
[29] L. Zhang, B. Lv, H. Yang, R. Xu, X. Wang, M. Xiao and J. Zhang, Nanoscale, 2019, 11, 12619-12625.
[30] Y. Shirasaki, G. J. Supran, W. A. Tisdale and V. Bulović, Phys. Rev. Lett., 2013, 110, 217403.
[31] Q. Hong, K. C. Lee, Z. Luo and S. T. Wu, Appl. Opt., 2015, 54, 4617-4622.
[32] J. Lim, S. Jun, E. Jang, H. Baik, H. Kim and J. Cho, Adv. Mater., 2007, 19, 1927-1932.
[33] E. Jang, S. Jun, H. Jang, J. Lim, B. Kim and Y. Kim, Adv. Mater., 2010, 22, 3076-3080.
[34] M. K. Choi, J. Yang, T. Hyeon and D. H. Kim, npj Flex. Electron., 2018, 2, 1-14.
[35] V. L. Colvin, M. C. Schlamp and A. P. Alivisatos, Nature, 1994, 370, 354-357.
[36] Z. Tan, F. Zhang, T. Zhu, J. Xu, A. Y. Wang, J. D. Dixon and J. Ruzyllo, Nano Lett., 2017, 7, 3803-3807.
[37] J. Kwak, W. K. Bae, D. Lee, I. Park, J. Lim, M Park and S. Lee, Nano Lett., 2012, 12, 2362-2366.
[38] J. Pan, C. Wei, L. Wang, J. Zhuang, Q. Huang, W. Su and J. Chen, Nanoscale, 2018, 10, 592-602.
[39] H. T. Nguyen, N. D. Nguyen and S. Lee, Nanotechnology, 2013, 24, 115201.
[40] H. K. Woo, M. S. Kang, T. Park, J. Bang, S. Jeon, W. S. Lee and D. H. Ha, Nanoscale, 2019, 11, 17498-17505.
[41] W. K. Bae, Y. S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel and V. I. Klimov, Nat. Commun., 2013, 4, 1-8.
[42] Y. H. Won, O. Cho, T. Kim, D. Y. Chung, T. Kim, H. Chung and E. Jang, Nature, 2019, 575, 634-638.
[43] H. Shen, Q. Gao, Y. Zhang, Y. Lin, Q. Lin, Z. Li and S. Wang, Nat. Photonics, 2019,13, 192-197.
[44] J. Y. Dong, W. Y. Ji, S. P. Wang, Q. L. Yuan, Y. C. Kong, S. C. Su and Z. K. Tang, ACS Appl. Electron. Mater., 2020, 2, 1074-1080.
[45] X. Huang, S. Su, Q. Su, H. Zhang, F. Wen and S. Chen, J. Soc. Inf. Disp., 2018, 26, 470-476.
[46] D. Dong, F. Zhu, S. Wu, L. Lian, H. Wang, D. Xu and G. He, Org. Electron., 2019, 68, 22-27.
[47] W. K. Bae, S. Brovelli and V. I. Klimov, MRS Bull., 2013, 38, 721.
[48] N. Kirkwood, B. Singh and P. Mulvaney, Adv. Mater. Interfaces, 2016, 3, 1600868.
[49] X. Dai, Z. Zhang, Y. Jin, Y. Niu, H. Cao, X. Liang and X. Peng, Nature, 2014, 515, 96-99.
[50] M. Rahmati, S. Dayneko, M. Pahlevani and Y. Shi, Adv. Funct. Mater., 2019, 29, 1906742.
[51] S. Kim, J. Kim, D. Kim, B. Kim, H. Chae, H. Yi and B. Hwang, ACS Appl. Mater. Interfaces, 2019, 11, 26333-26338.
[52] Y. Sun, Y. Jiang, H. Peng, J. Wei, S. Zhang and S. Chen, Nanoscale, 2017, 9, 8962-8969.
[53] J. H. Kim, C. Y. Han, K. H. Lee, K. S. An, W. Song, J. Kim and H. Yang, Chem. Mater., 2015, 27, 197-204.
[54] Y. Sun, W. Wang, H. Zhang, Q. Su, J. Wei, P. Liu and S. Zhang, ACS Appl. Mater. Interfaces, 2018, 10, 18902-18909.
[55] E. Tamburri, S. Sarti, S. Orlanducci, M. L. Terranova and M. Rossi, Mater. Chem. Phys., 2011, 125, 397-404.
[56] Y. Song, Q. D. Ling, S. L. Lim, E. Y. H. Teo, Y. P. Tan, L. Li and C. Zhu, IEEE Electron Device Lett., 2007, 28, 107-110.
[57] S. K. Kim, J. H. Kim, H. S. Yang and Y. S. Kim, Dig. Tech. Pap., 2018, 49, 1632-1635.
[58] J. W. Lee, J. K. Kim and Y. S. Yoon, Chin. J. Chem., 2010, 28, 115-118.
[59] H. Zhang, S. Wang, X. Sun and S. Chen, J. Mater. Chem. C, 2017, 5, 817-823.
[60] W. B. Stockton and M. F. Rubner, Macromolecules, 1997, 30, 2717-2725.
[61] M. D. Ho, D. Kim, N. Kim, S. M. Cho and H. Chae, ACS Appl. Mater. Interfaces, 2013, 5, 12369-12374.
[62] J. Kwak, W. K. Bae, D. Lee, I. Park, J. Lim, M. Park and S. Lee, Nano Lett., 2012, 12, 2362-2366.
[63] Y. Liu, Z. Hong, Q. Chen, H. Chen, W. H. Chang, Y. Yang, T. B. Song and Y. Yang, Adv. Mater., 2016 28, 440-446.
[64] T. H. Schloemer, J. A. Christians, J. M. Luther and A. Sellinger, Chem. Sci., 2019, 10, 1904-1935.
[65] B. Liu, L. Lan, Y. Liu, H. Tao, H. Li, H. Xu, J. Zou, M. Xu L. Wang and Y. Cao, Org. Electron., 2019, 74, 144-151.
[66] K. Rakstys, C. Igci and M. K. Nazeeruddin, Chem. Sci., 2019, 10, 6748-6769.
[67] J. Pan, J. Chen, Q. Huang, L. Wang and W. Lei, RSC Adv., 2017, 7, 43366-43372.
[68] M. D. Ho, D. Kim, N. Kim, S. M. Cho and H. Chae, ACS Appl. Mater. Interfaces, 2013, 5, 12369-12374.
[69] Y. Liu, C. Jiang, C. Song, J. Wang, L. Mu, Z. He and J. Peng, ACS Nano, 2018, 12, 1564-1570.
[70] W. Zheng, D. Song, S. Zhao, B. Qiao, Z. Xu, J. Chen and Y. Liang, Org. Electron., 2020, 77, 105544.
[71] X. Yang, Y. Ma, E. Mutlugun, Y. Zhao, K. S. Leck, S. T. Tan and X. W. Sun, ACS Appl. Mater. Interfaces, 2014, 6, 495-499.
[72] C. Jiang, H. Liu, B. Liu, Z. Zhong, J. Zou, J. Wang and Y. Cao, Org. Electron., 2016, 31, 82-89.
[73] H. Ma, H. L. Yip, F. Huang and A. K. Y. Jen, Adv. Funct. Mater., 2010, 20, 1371-1388.
[74] W. Zheng, D. Song, S. Zhao, B. Qiao, Z. Xu, J. Chen and Y. Liang, Org. Electron., 2020, 77, 105544.
[75] L. Wang, T. Chen, Q. Lin, H. Shen, A. Wang, H. Wang and L. S. Li, Org. Electron., 2016, 37, 280-286.
[76] J. Wu, J. Xia and W. Lei, Org. Electron., 2019, 67, 116-121.
[77] L. Liu, , X. Liu, K. Wu, J. Ding, B. Zhang, Z. Xie and L. Wang, Org. Electron., 2014, 15, 1401-1406.
[78] F. O. O. Ngome, Y. T. Kim, H. D. Lee, Y. H. Kim, T. W. Lee and C. G. Park, J. Mater. Chem. C, 2017, 5, 9761-9769.
[79] H. Cho, S. Park, H. Shin, M. Kim, H. Jang, J. Park and D. Y. Jeon, Small, 2020, 16, 2002109.
[80] J. Wu, X. Zhang, J. Xia, W. Lei and B. Wang, Org. Electron., 2018, 62, 434-440.
[81] E. Petryayeva, W. R. Algar and I. L. Medintz, Appl. Spectrosc., 2013, 67, 215-252.
[82] P. Guo, J. Jiang, S. Shen and L. Guo, Int. J. Hydrog. Energy, 2013, 38, 13097-13103.
[83] W. Ji, P. Jing, W. Xu, X. Yuan, Y. Wang, J. Zhao and A. K. Y. Jen, Appl. Phys. Lett., 2013, 103, 053106.
[84] D. Dong, F. Zhu, S. Wu, L. Lian, H. Wang, D. Xu and G. H, Org. Electron., 2019, 68, 22-27.
[85] H. M. Kim, J. Kim and J. Jang, Nanoscale, 2018, 10, 7281-7290.
[86] F. Wang, W. Sun, P. Liu, Z. Wang, J. Zhang, J. Wei and Z. A. Tan, J. Phys. Chem. Lett., 2019, 10, 960-965.
[87] K. Sun, F. Li, Q. Zeng, H. Hu and T. Guo, Org. Electron., 2018, 63, 65-70.
[88] Y. Sun, Y. Jiang, X. W. Sun, S. Zhang and S. Chen, Chem. Rec., 2019, 19, 1729-1752.
[89] H. Qi, S. Wang, X. Jiang, Y. Fang, A. Wang, H. Shen and Z. Du, J. Mate. Chem. C, 2020, 8, 10160-10173.
[90] B. Mashford, J. Baldauf, T. L. Nguyen, A. M. Funston and P. Mulvaney, J. Apply. Phys., 2011, 9, 094305.
[91] S. Shendre, V. K. Sharma, C. Dang and H. V. Demir, ACS Photonics, 2018, 2, 480-486.
[92] J. A. Brum and G. Bastard, Phys. Rev. B, 1985, 31, 3893.
[93] J. W. Christopher, B. B. Goldberg and A. K. Swan, Sci. Rep., 2017, 7, 1-8.
[94] D. F. Blossey, Phys. Rev. B, 1971, 3, 1382.
[95] W. Xiang, Z. Wang, D. J. Kubicki, X. Wang, W. Tress, J. Luo and M. Grätzel, Nat. Commun., 2019, 10, 1-8.
[96] J. Pan, J. Chen, Q. Huang, Q. Khan, X. Liu, Z. Tao and Z. Zhang, RSC Adv., 2015, 5, 82192-82198.
[97] C. Jiang, Z. Zhong, B. Liu, Z. He, J. Zou, L. Wang and Y. Cao, ACS Appl. Mater. Interfaces, 2016, 8, 26162-26168.
[98] S. Shen, Z. Guan, P. Lv, W. Bi, Z. Chen, A. Tang and F. Teng, Org. Electron., 2020, 105790.
[99] J. Li, Z. Liang, Q. Su, H. Jin, K. Wang, G. Xu and X. Xu, ACS Appl. Mater. Interfaces, 2018, 10, 3865-3873.
[100] J. Panidi, A. F. Paterson, D. Khim, Z. Fei, Y. Han, L. Tsetseris and T. D. Anthopoulos, Adv. Sci., 2018, 5, 1700290.
[101] H. A. Al‐Attar and A. P. Monkman, Adv. Funct. Mater., 2012, 22, 3824-3832.
[102] L. Duan, L. Hou, T. W. Lee, J. Qiao, D. Zhang, G. Dong and Y. Qiu, J. Mater. Chem., 2010, 20, 6392-6407.