本文驗證了藉由優化主動層厚度可以有效改善固態有機白光電化學元 件 的 效 率 , 其 主 動 層 材 料 是 使 用 效 率 很 高 且 發 藍 綠 光 的 [Ir(dfppz)2(dtb-bpy)]+(PF6
─) 當 做 主 體 材 料 並 少 量 摻 雜 發 紅 光 的 [Ir(ppy)2(biq)]+(PF6
─)當做客體材料所製作而成的白光元件。
本文使用 Matlab 程式模擬穩定電致發光頻譜可以得知,當主動層厚度 從 190 奈米(元件 I)增加到 270 奈米(元件 II)時,複合區會慢慢移動到主動 層的中心位置使複合區與電極(或摻雜層)間的距離增加而緩解了激子猝熄,
因此顯著的提昇了元件效率(高達 1.5 倍)分別為 11 %的外部量子效率以及 20 流明/瓦的功率效率,這是目前已發表固態有機白光電化學元件的文獻中 的最高效率,然而更進一步將元件主動層厚度提高到 400 奈米(元件 III)卻 發現載子遷移率的平衡產生惡化,且在相同驅動電壓下主動層較厚的元件 相對電場較低也會導致載子注入變差,因此在主動層內的複合區位置變得 更不對稱。這些實驗結果可以發現固態有機白光電化學元件確實可由優化 主動層厚度來得到激子猝熄現象最少的最高效率元件。
參考文獻:
[1] M. Pope, H. P. Kallmann, and P. Magnante, "Electroluminescence in Organic Crystals",The Journal of Chemical Physics,38,2042 (1963)
[2] C. W. Tang and S. A. VanSlyke,"Organic electroluminescent diodes",Applied Physics Letters,51,913 (1987)
[3] C. W. Tang, S. A. VanSlyke, and C.H. Chen, "Electroluminescence of doped organic thin films", Journal of Applied Physics,65,3610 (1989)
[4] 陳金鑫,黃孝文, "夢幻顯示器:OLED 材料與元件",初版,台灣,五南圖書出 版,(2007)
[5] J. H. Burroughes, et al., "Light-emitting diodes based on conjugated polymers",Nature,347,539 (1990)
[6] Q. Pei, G. Yu, C. Zhang, Y. Yang, A. J. Heeger, "Polymer Light-Emitting Electrochemical Cells",Science,269,1086 (1995)
[7] Q. Pei, Y. Yang, G. Yu, C. Zhang , A. J. Heeger, "Polymer Light-Emitting Electrochemical Cells: In Situ Formation of a Light-Emitting p-n Junction",J. Am. Chem. Soc.,118,3922 (1996)
[8] J. K. Lee, D. S. Yoo, E. S. Handy, and M. F. Rubner, "Thin film light emitting devices from an electroluminescent ruthenium complex",Applied Physics Letters,69,1686 (1996)
[9] E. S. Handy, A. J. Pal, and M. F. Rubner, "Solid-State Light-Emitting Devices Based on the Tris-Chelated Ruthenium(II) Complex. 2.
Tris(bipyridyl) ruthenium(II) as a High-Brightness Emitter", J. Am. Chem.
Soc.,121,3525 (1999)
[10] J. D. Slinker, et al., "Electroluminescent devices from ionic transition metal complexes",Journal of Materials Chemistry,17,2976 (2007)
[11] C. H. Lyons, E. D. Abbas, J.-K. Lee, and M. F. Rubner, "Solid-State Light-Emitting Devices Based on the Trischelated Ruthenium(II) Complex.
1. Thin Film Blends with Poly(ethylene oxide) ",J. Am. Chem.
Soc.,120,12100 (1998)
[12] F. G. Gao and A. J. Bard, "Solid-State Organic Light-Emitting Diodes Based on Tris(2,2´-bipyridine) ruthenium(II) Complexes",J. Am. Chem.
Soc.,122,7426 (2000)
[13] H. Rudmann and M. F. Rubner, "Single layer light-emitting devices with high efficiency and long lifetime based on tris(2,2´ bipyridyl) ruthenium(II) hexafluorophosphate",Journal of Applied Physics,90,4338 (2001)
[14] H. Rudmann, S. Shimada, and M. F. Rubner, "Solid-State Light-Emitting Devices Based on the Tris-Chelated Ruthenium(II) Complex. 4.
High-Efficiency Light-Emitting Devices Based on Derivatives of the Tris(2,2´-bipyridyl) Ruthenium(II) Complex",J. Am. Chem. Soc.,124,4918 (2002)
[15] G. Kalyuzhny, M. Buda, J. McNeill, P. Barbara, and A. J. Bard, "Stability of Thin-Film Solid-State Electroluminescent Devices Based on Tris(2,2´-bipyridine) ruthenium(II) Complexes",J. Am. Chem.
Soc.,125,6272 (2003)
[16] H. Rudmann, S. Shimada, and M. F. Rubner, "Operational mechanism of light-emitting devices based on Ru(II) complexes: Evidence for electrochemical junction formation",Journal of Applied Physics,94,115 (2003)
[17] J. D. Slinker, et al., "Solid-state electroluminescent devices based on transition metal complexes",Chem. Commun.,2392 (2003)
[18] K. W. Lee, et al., "Photophysical properties of tris(bipyridyl)ruthenium(II) thin films and devices",Phys. Chem. Chem. Phys.,5,2706 (2003)
[19] J. D. Slinker, et al., "Efficient Yellow Electroluminescence from a Single Layer of a Cyclometalated Iridium Complex", J. Am. Chem. Soc.,126,2763 (2004)
[20] J. D. Slinker, C. Y. Koh, and G. G. Malliaras, "Green electroluminescence from an ionic iridium complex",Applied Physics Letters,86,173506 (2005) [21] A. R. Hosseini, et al., "Addition of a Phosphorescent Dopant in
Electroluminescent Devices from Ionic Transition Metal Complexes",Chem Mater.,17,6117 (2005)
[22] S. T. Parker, et al., "Improved Turn-on Times of Iridium Electroluminescent Devices by Use of Ionic Liquids",Chem Mater.,17,3187 (2005)
[23] M. S. Lowry, et al., "Single-Layer Electroluminescent Devices and Photoinduced Hydrogen Production from an Ionic Iridium(III) Complex",Chem Mater.,17,5712 (2005)
[24] A. B. Tamayo, et al., "Cationic Bis-cyclometalated Iridium(III) Diimine Complexes and Their Use in Efficient Blue, Green, and Red Electroluminescent Devices",Inorg. Chem,44,8723 (2005)
[25] N. Armaroli, et al., "Highly Luminescent CuI Complexes for Light-Emitting Electrochemical Cells",Adv. Mater.,18,1313 (2006)
[26] H. C. Su, et al., "Efficient solid-state host-guest light-emitting electrochemical cells based on cationic transition metal complexes", Applied Physics Letters,89,261118 (2006)
[27] H. J. Bolink, et al., "Green Light-Emitting Solid-State Electrochemical Cell Obtained from a Homoleptic Iridium(III) Complex Containing Ionically Charged Ligands",Chem Mater.,18,2778 (2006)
[28] M. K. Nazeeruddin, et al., "Efficient Green-Blue-Light-Emitting Cationic Iridium Complex for Light-Emitting Electrochemical Cells",Inorg.
Chem,45,9245 (2006)
[29] H. J. Bolink, et al., " Efficient and Stable Solid-State Light-Emitting
Electrochemical Cell Using
Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) Hexafluorophosphate", J. Am. Chem. Soc.,128,46 (2006)
[30] H. J. Bolink, et al., " Stable Single-Layer Light-Emitting Electrochemical
Cell Using
4,7-Diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) Hexafluorophosphate", J. Am. Chem. Soc.,128,14786 (2006)
[31] Q. Zhang, et al., "Highly Efficient Electroluminescence from Green-Light-Emitting Electrochemical Cells Based on CuI Complexes",Adv.
Funct. Mater.,16,1203 (2006)
[32] H. C. Su, et al., "Highly Efficient Orange and Green Solid-State Light-Emitting Electrochemical Cells Based on Cationic IrIII Complexes with Enhanced Steric Hindrance", Adv. Funct. Mater.,17,1019 (2007)
[33] H. J. Bolink, et al., " Long-Living Light-Emitting Electrochemical Cells – Control through Supramolecular Interactions", Adv. Mater.,20,3910 (2008) [34] H. C. Su, H. F. Chen, C. C. Wu, and K. T. Wong, "Decreased Turn-On
Times of Single-Component Light-Emitting Electrochemical Cells by Tethering an Ionic Iridium Complex with Imidazolium Moieties",Chem.
Asian J.,3,1922 (2008)
[35] E. Z. Colman, et al., "Improved Turn-On Times of Light-Emitting Electrochemical Cells",Chem. Mater.,20,388 (2008)
[36] H. J. Bolink, et al., "Near-Quantitative Internal Quantum Efficiency in a Light-Emitting Electrochemical Cell",Inorg. Chem.,47,9149 (2008)
[37] S. Graber, et al., "A Supramolecularly-Caged Ionic Iridium(III) Complex Yielding Bright and Very Stable Solid-State Light-Emitting Electrochemical Cells", J. Am. Chem. Soc.,130,14944 (2008)
[38] L. He, et al., "Blue-Emitting Cationic Iridium Complexes with 2-(1H-Pyrazol-1-yl)pyridine as the Ancillary Ligand for Efficient Light-Emitting Electrochemical Cells", Adv. Funct. Mater.,18,2123 (2008) [39] R. D. Costa, et al., "Archetype Cationic Iridium Complexes and Their Use
in Solid-State Light-Emitting Electrochemical Cells",Adv. Funct.
Mater.,19,3456 (2009)
[40] R. D. Costa, et al., "Two are not always better than one: ligand optimisation for long-living light-emitting electrochemical cells",Chem. Commun.,2029 (2009)
[41] C. Rothe, et al., "Ionic Iridium(III) Complexes with Bulky Side Groups for
Use in Light Emitting Cells: Reduction of Concentration Quenching", Adv.
Funct. Mater.,19,2038 (2009)
[42] T. H. Kwon, Y. H. Oh, I. S. Shin, and J. I. Hong, "New Approach Toward Fast Response Light-Emitting Electrochemical Cells Based on Neutral Iridium Complexes via Cation Transport", Adv. Funct. Mater.,19,711 (2009) [43] L. He, et al., "Toward Highly Efficient Solid-State White Light-Emitting
Electrochemical Cells: Blue-Green to Red Emitting Cationic Iridium Complexes with Imidazole-Type Ancillary Ligands", Adv. Funct.
Mater.,19,2950 (2009)
[44] R. D. Costa, et al., "Efficient and Long-Living Light-Emitting Electrochemical Cells", Adv. Funct. Mater.,20,1511 (2010)
[45] R. D. Costa, et al., "Intramolecular π-Stacking in a Phenylpyrazole-Based Iridium Complex and Its Use in Light-Emitting Electrochemical Cells", J.
Am. Chem. Soc.,132,5978 (2010)
[46] M. Mydlak, et al., "Positively Charged Iridium(III) Triazole Derivatives as Blue Emitters for Light-Emitting Electrochemical Cells",Adv. Funct.
Mater.,20,1812 (2010)
[47] C. H. Yang, et al., "Iridium Metal Complexes Containing N-Heterocyclic Carbene Ligands for Blue-Light-Emitting Electrochemical Cells",Inorg.
Chem.,49,9891 (2010)
[48] H. C. Su, et al., "Solid-state light-emitting electrochemical cells employing phosphorsensitized fluorescence",Journal of Materials Chemistry,20,5521 (2010)
[49] M. Lenes, et al., "Operating Modes of Sandwiched Light-Emitting Electrochemical Cells", Adv. Funct. Mater.,21,1581 (2011)
[50] J. Kido, K. Hongawa, K. Okuyama, and K. Nagai, "White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter llayer doped with three fluorescent dyes", Applied Physics Letters,64,815 (1994)
[51] Y. Yang, and Q. Pei, "Efficient blue-green and white light-emitting electrochemical cells based on poly[9,9-bis(3,6-dioxaheptyl)-fluorene-2,7-diyl]",Journal of Applied Physics,81,3294 (1997)
[52] M. Sun, C. Zhong, F. Li, Yong Cao, and Qibing Pei, "A Fluorene-Oxadiazole Copolymer for White Light-Emitting Electrochemical Cells", J. Am. Chem. Soc.,43,1714 (2010)
[53] S. Tang, J. Pan, H. Buchholz, and L. Edman, "White Light-Emitting Electrochemical Cell",Appl. Mater. Inter.,3,3384 (2011)
[54] S. Tang, J. Pan, H. A. Buchholz, and L. Edman, "White Light from a Single-Emitter Light-Emitting Electrochemical Cell",J. Am. Chem.
Soc.,135,3647 (2013)
[55] C. S. Tsai, S. H. Yang, B. C. Liu, H. C. Su, "Single-component polyfluorene electrolytes bearing different counterions for white light-emitting electrochemical cells",Organic Electronics,14,483 (2013)
[56] H. C. Su, et al., "Solid-State White Light-Emitting Electrochemical Cells Using Iridium-Based Cationic Transition Metal Complexes",J. Am. Chem.
Soc.,130,3413 (2008)
[57] L. He, et al., "Highly Efficient Blue-Green and White Light-Emitting Electrochemical Cells Based on a Cationic Iridium Complex with a Bulky Side Group",Chem. Mater.,22,3535 (2010)
[58] H. C. Su, et al., "Highly efficient double-doped solid-state white light-emitting electrochemical cells",Journal of Materials Chemistry,21,9653 (2011)
[59] H. B. Wu, et al., "Efficient and color-stable solid-state white light-emitting electrochemical cells employing red color conversion layers",Organic Electronics,13,483 (2012)
[60] H. C. Su, et al., "Efficient solid-state white light-emitting electrochemical cells based on phosphorescent sensitization",Journal of Materials
Chemistry,22,22998 (2012)
[61] J. C. deMello, "Organic electronics: What´s in a name?",Nature Materials,6,796 (2007)
[62] S. V. Reenen et al., "A Unifying Model for the Operation of Light-Emitting Electrochemical Cells", J. Am. Chem. Soc.,132,13776 (2010)
[63] R. D. Costa et al., "Luminescent Ionic Transition-Metal Complexes for Light-Emitting Electrochemical Cells",Angew. Chem. Int. Ed.,51,8178 (2012)
[64] T. Hu et al., "Solid-state light-emitting electrochemical cells based on ionic iridium(III) complexes", Journal of Materials Chemistry,22,4206 (2012) [65] X. Liu, D. Poitras, Y. Tao, C. Py, "Microcavity organic light emitting
diodes with double sided light emission of different colors",J. Vac. Sci.
Technol. ,22 ,764 (2004)
[66] T. W. Wang, H. C. Su, "Extracting evolution of recombination zone position in sandwiched solid-state light-emitting electrochemical cells by employing microcavity effect",Org. Electron,14 , accepted. (2013)
[67] I. H. Campbell, D. L. Smith, C. J. Neef, J. P. Ferraris, "Capacitance measurements of junction formation and structure in polymer light-emitting electrochemical cells", Applied Physics Letters,72,2565 (1998)