Study on Application of Tris-(Pinene-2-Phenylpyridine) Iridium (III) Complexes Attached Alkoxy Groups in Polymer Light-Emitting Diodes

doi:10.7517/j.issn.1674-0475.2008.01.16

Abstract

Abstract: A new family of Tris-(pinene-2-phenylpyridine) Iridium (III) complexes attached alkoxy groups were doped in PVK and polymer devices ITO/PEDOT:PSS (40 nm)/PVK_0.7:PBD_0.3: (x%.) Ir-complex (80 nm)/CsF (1.5 nm)/Mg:Ag (200 nm) were fabricated by spin-coating.The results indicated that the devices of the Ir-complex attached hexadecoxy groups exhibit better performance.The maximum luminance efficiency 19.9 cd/A (7.8 lm/W) at 9.1V was obtained with doping concentration of 3.2%,CIE coordinates (0.20,0.56),and the maximum luminance of the devices was 15700 cd/m² at 8.4 V.Orbit alignment and energy transfer mechanism between the host material and dopant were studied by their photophysics and electrochemistry properties.

Key words: iridium complex, phosphorescent materials, polymer light-emitting diodes, energy transfer

CLC Number:

HE Jian, LIU Hong-mei, ZHENG Cai-jun, WANG Jing, ZHANG Xiao-hong. Study on Application of Tris-(Pinene-2-Phenylpyridine) Iridium (III) Complexes Attached Alkoxy Groups in Polymer Light-Emitting Diodes[J]. Imaging Science and Photochemistry, 2008, 26(1): 16-24.

References

[1] Burroughes J H,Bradley D D C,Brown A R,et al.Light-emitting diodes based on conjugated polymers[J].Nature,1990,347:539-541.
[2] Baldo M A,O'Brien D F,You Y,et al.Highly efficient phosphorescent emission from organic electroluminescent devices[J].Nature,1998,395:151-154.
[3] O'Brien D F,Baldo M A,Thompson M E,et al.Improved energy transfer in electrophosphorescent devices[J].Appl.Phys.Lett.,1999,74:442-444.
[4] Hung L S,Chen C H.Recent progress of molecular organic electroluminescent materials and devices[J].Mater.Sci.Eng.R.,2002,39:143-222.
[5] 吴世康,张晓宏,李述汤.磷光电致发光器件研究中的若干问题[J].化学进展,2001,13:413-419.Wu S K,Zhang X H,Lee S T.Problems in the study of electro-luminescence devices based on phosphorescent dyes[J].Progress in Chemistry,2001,13:413-419.
[6] Markham J P J,Lo S C,Magennis S W,et al.High-efficiency green phosphorescence from spin-coated single-layer dendrimer light-emitting diodes[J].Appl.Phys.Lett.,2002,80:2645-2647.
[7] Gong X,Robinson MR,Ostrowski JC,et al.High-efficiency polymer-based electrophosphorescent devices[J].Adv.Mater.,2002,14.581-585.
[8] Xie H Z,Liu M W,Wang O Y,et al.Reduction of self-quenching effect in organic electrophosphorescence emitting devices via the use of sterically hindered spacers in phosphorescence molecules[J].Adv.Mater.,2001,13:1245-1248.
[9] Chew S,Lee C S,Lee S T,et al.Photoluminescence and electroluminescence of a new blue-emitting homoleptic iridium complex[J].Appl.Phys.Lett.,2006,88:093510-093512.
[10] Liu H M,He J,Wang P F,et al.High-efficiency polymer electrophosphorescent diodes based on an Ir(Ⅲ)complex[J].Appl.Phys.Lett.,2005,87:221103-221105.
[11] 何鉴,汪鹏飞,刘红梅,等.带烷氧基的苯基蒎烯吡啶铱配合物的合成及光物理性质[J].高等学校化学学报,2007,28(4):678-682.He J,Wang P F,Liu H M,et al.Synthesis and photophysical characterization of tris-(pinene-2-phenylpyridine)iridium complexes with alkyloxy groups[J].Chem.J.Chin.Univ.,2007,28(4):678-682.
[12] Sonntag M,Strohriegl P.Novel 2,7-linked carbazole trimers as model compounds for conjugated carbazole polymers[J].Chem.Mater.,2004,16:4736-4742.
[13] Mason M G,Hung L S,Tang W C,et al.Characterization of treated indium-tin-oxide surfaces used in electroluminescent devices[J].J.Appl.Phys.,1999,86:1688-1692.
[14] 黄春辉,李富友,黄维.有机电致发光材料和器件导论[M].上海:复旦大学出版社,2005.110-111.Huang C H,Li F Y,Huang W.Introduction to Organic Light-emitting Materials and Devices[M].Shanghai:Fudan University Press,2005.110-111.
[15] 藤嵨昭等著;陈震,姚建年译.电化学测定方法[M].北京:北京大学出版社,1995.90-92.Fujishima S,et al.translated by Chen Z,Yao J N.Electrochem Determ Methods[M].Beijing:Peking University Press,1995.90-92.
[16] Chen F C,Chang S C,He G,et al.Energy transfer and triplet exciton confinement in polymeric electrophosphorescent devices[J].J.Polymer Science:Polymer Physics,2003,41:2681-2690.
[17] Chang S C,He G,Chen F C,et al.Degradation mechanism of phosphorescent-dye-doped polymer light-emitting diodes[J].Appl.Phys.Lett.,2001,79:2088-2090.
[18] Lamansky S,Kwong R C,Nugent M,et al.Molecularly doped polymer light emitting diodes utilizing phosphorescent Pt(Ⅱ)and Ir(Ⅲ)dopants[J].Org.Electron.,2001,2:53-62.
[19] Adachi C,Tsutsui T,Saito S.Organic electroluminescent device having a hole conductor as an emitting layer[J].Appl.Phys.Lett.,1989,55:1489-1491.
[20] Brown T M,Kim J S,Friend R H,et al.Built-in field electroabsorption spectroscopy of polymer light-emitting diodes incorporating a doped poly(3,4-ethylene dioxythiophene)hole injection layer[J].Appl.Phys.Lett.,1999,75:1679-1681.
[21] Jabbour G E,Kippelen B,Armstrong N R,et al.Aluminum based cathode structure for enhanced electron injection in electroluminescent organic devices[J].Appl.Phys.Lett.,1998,73:1185-1187.
[22] Jiang C,Yang W,Peng J B,et al.High-efficiency,saturated red-phosphorescent polymer light-emitting diodes based on conjugated and non-conjugated polymers doped with an Ir complex[J].Adv.Mater.,2004,16:537-541.
[23] Gong X,Robinson M R,Ostrowski J C,et al.High-efficiency polymer-based electrophosphorescent devices advanced materials[J].Adv.Mater.,2002,14:581-585.
[24] Thoms T,Okada S,Chen J P.Improved host material design for phosphorescent guest-host systems[J].Thin Solid Film,2003,436:264-268.
[25] Tsuboyama A,Iwawaki H,Furugori M,et al.Homoleptic cyclometalated iridium complexes with highly efficient red phosphorescence and application to organic light-emitting diode[J].J.Am.Chem.Soc.,2003,25:12971-12979.
[26] Tokito S,Iijima T,Suzuri Y,et al.Confinement of triplet energy on phosphorescent molecules for highly-efficient organic blue-light-emitting devices[J].Appl.Phys.Lett.,2003,83:569-571.
[27] Adachi C,Kwong R C,Djurovich P,et al.Endothermic energy transfer:A mechanism for generating very efficient high-energy phosphorescent emission in organic materials[J].Appl.Phys.Lett.,2001,79:2082-2084.
[28] K Walter,F Dieter.Triplet energy transfer in solid solutions and films of poly(vinyl carbazole)[J].J.Polymer Sci.:Symposium,1973,40:43-56.
[29] Wittmann H F,Friend R H,Khan M S,et al.Optical spectroscopy of platinum and palladium containing poly-ynes[J].J.Chem.Phys.,1994,101:2693-2698.
[30] Baldo M A,Lamansky S,Burrows P E,et al.Very high-efficiency green organic light-emitting devices based on electrophosphorescence[J].Appl.Phys.Lett.,1999,75:4-6.