Synthesis and luminescent properties of iridium complexes with reduced concentration quenching effect

Abstract

Three novel cyclometalated ligands 1-benzyl-2-phenyl-1H-benzoimidazole(BPBM), 1-(4-methoxy-benzyl)-2-(4-methoxy-phenyl)-1H-benzoimidazole(MBMPB) and 4-[2-(4-dimethylamino-phenyl)-benzoinidazol-1-ylmethyl]-phenyl-dimethyl-amine(DBPA) were designed and synthesized, and the corresponding highly efficiency green-emitting phosphorescent iridium complexes Ir(BPBM)₂(acac)(1), Ir(MBMPB)₂(acac)(2) and Ir(DPBA)₂(acac) (3) with acetylacetone(acac) as auxiliary ligand were also synthesized. The ligands are functionalized by bulky non-planarity substituents, thus the phosphorescent concentration quenching is substantially suppressed, and all the complexes exhibit bright photoluminescence(PL) in solid state. The photo-physical properties of the three iridium complexes were researched in detail. The results indicate that they have potential application in fabricating non-doped electrophosphorescence device.

Keywords

Green-emitting / Iridium complex / Bulky non-planarity substituent

References

[1] Adachi C, Baldo M A, Forrest S R, Thompson M E. Appl. Phys. Lett., 2000, 77: 904.

[2] Ma Y G, Zhang H Y, Shen J C, Che C M. Synth. Met., 1998, 94: 245.

[3] Bian Z Q, Gao D Q, Sun C Y, Wang K Z, Jin L P, Huang C H. Chem. Res. Chinese Universities, 2002, 18(4): 466.

[4] Tsuboyama A, Iwawaki H, Furugori M, Mukaide T, Kamatani J, Igawa S, Moriyama T, Miura S, Takiguchi T, Okada S, Hoshino M, Ueno K. J. Am. Chem. Soc., 2003, 125(42): 12971.

[5] Xin H, Li F Y, Shi M, Bian Z Q, Huang C H. J. Am. Chem. Soc., 2003, 125: 7166.

[6] Yang C H, Fang K H, Chen C H, Sun I W. Chem. Commun., 2004, 2232.

[7] Liu Y, Liu S L, Wang Y G. Chem. Res. Chinese Universities, 2010, 26(2): 249.

[8] Yang C H, Tai C C, Sun I W. J. Mater. Chem., 2004, 14(6): 947.

[9] Lupton J M, Samuel I D W, Frampton M J, Beavington R, Burn P L. Adv. Funct. Mater., 2001, 11: 287.

[10] Liu J, Chen H B, Liu S G. Chem. Res. Chinese Universities, 2012, 28(4): 572.

[11] Liu Z W, Guan M, Bian Z Q, Nie D B, Gong Z L, Li Z B, Huang C H. Adv. Funct. Mater., 2006, 16: 1441.

[12] Ding J Q, Gao J, Cheng Y X, Xie Z Y, Wang L X, Ma D G, Jing X B, Wang F S. Adv. Funct. Mater., 2006, 16: 575.

[13] Markham J P J, Lo S C, Magennis S W, Burn P L, Samuel I D W. Appl. Phys. Lett., 2002, 80: 2645.

[14] Zhou G C, Ho L, Wong W Y, Wang Q, Ma D G, Wang L X, Lin Z Y, Marder T B, Beeby A. Adv. Funct. Mater., 2008, 18: 499.

[15] Chou P T, Chi Y. Chem. Eur. J., 2007, 13: 380.

[16] Ashwini K A, Samson A. J. Chem. Mater., 1996, 8: 579.

[17] Kober E M, Caspar J V, Lumpkin R S, Meyer T J. J. Phys. Chem., 1986, 90: 3722.

[18] Spellane P, Watts R J, Vogler A. Inorg. Chem., 1993, 32: 5633.

[19] Strickler S J, Berg R A J. J. Chem. Phys., 1962, 37: 814.

[20] Einstein A. Phys. Z., 1917, 18: 121.

[21] Zhang J P, Jin L, Zhang H X, Bai F Q. Chem. J. Chinese Universities, 2011, 32(12): 2885.