The Organic-Transition Metal Complex and the Emission of Triplet States

doi:10.7517/j.issn.1674-0475.2011.02.81

Abstract

Abstract: In recent years,the emission of triplet state of organic-transition metal complex attracted extensive attentions with the development of OLED devices.It not only concerns with the increase the device efficiency,but also with some problems deeply in the field of photo-physics.In this article,the energy level splitting of organic-metallic compounds,and the zero-field splitting(ZFS) of emissive triplet state are discussed briefly.Simultaneously,the relationship of electronic configuration of centered metallic ions,such as the octahedral and square planar coordination and their photo-physical behaviors are also discussed.Especially,the emission state of these compounds,under the influence of spin-orbital coupling(SOC) and configuration interaction(CI) which can induce the admixture of singlet and triplet state,then to improve the emissive transition from the lowest triplet state to ground state,has also been discussed.

Key words: organic-transition metal complex, zero-field splitting(ZFS), spin-orbital coupling(SOC), photo-physical behaviors, emission of triplet state

CLC Number:

WU Shi-kang, WANG Peng-fei. The Organic-Transition Metal Complex and the Emission of Triplet States[J]. Imaging Science and Photochemistry, 2011, 29(2): 81-98.

References

[1] Baldo M A,Thompson M E,Forrest S R.Phosphorescent materials for application to organic light emitting de-vices[J].Pure Appl.Chem.,1999,71:2095.
[2] Adachi C,Baldo M A,Thompson M E,Forrest S R.Nearly 100% internal quantum efficiency in an organiclight-emitting device[J].J.Appl.Phys.2001,90:5048.
[3] Yersin H,Finkenzeller W J.Triplet emitters for organic light-emitting diodes:basic properties,inHighly Effi-cient OLEDs with Phosphorescent Materials[M].Ed.Hartmut Yersin,WILEY-VCH Verlag GmbH&Co.Weinheim,2008.
[4] Klessinger M.Elektronenstruktur Organischer Molekule[M].Verlag Chemie,Weinheim,1982.
[5] McGlynn S P,Azumi T,Kinoshita M.Molecular Spectroscopy of the Triplet State[M].Prentice-Hall,En-glewood Cliffs,New Jersey,1969.
[6] Turro N J.Modern Molecular Photochemistry[M].Benjamin-Cummings,Menlo Park,Calif.1978.31.
[7] Mataga N,Kubota T.Molecular Interactions and Electronic Spectra[M].Marcel Dekker,NewYork,1970.187.
[8] Kohler A,Bassler H.Triplet states in organic semiconductors[J].Materials Science and Engineering R,2009,66:71-109.
[9] Maestri M,Sandrini D,Balzani V,Chassot L,Jolliet P,A.von Zelewsky.Luminescence of ortho-metallatedplatinum(ii)complexes[J].Chem.Phys.Lett.,1985,122,375.
[10] Yersin H,Donges D.Low-lying electronic states and photophysical properties of organometallic Pd(II)and Pt(II)compounds.Modern research trends presented in detailed case studies in:Transition Metal and RareEarth Compounds.Excited States,Transitions and Interactions,Vol.II Springer-Verlag Berlin,ed.YersinH.,Top.Curr.Chem.2001,214:81.
[11] Jolly W L.Modern Inorganic Chemistry[M].McGraw-Hill,New York,1984.
[12] Yersin H,Humbs W,Strasser J.Characterization of excited electronic and vibronic states of platinum metalcompounds with chelate ligands by highly frequency-resolved and time-resolved spectra.Electronic and VibronicSpectra of Transition Metal Complexes,Vol.II Springer-Verlag Berlin,ed.Yersin H.,Top.Curr.Chem.1997,191:153.
[13] Yersin H,Humbs W.Spatial extensions of excited states of metal-organic Pt(II)compound in a Shpolskii ma-trix[J].Inorg.Chem.,1999,38:5820.
[14] Glasbeek M.Excited state spectroscopy and excited state dynamics of Rh(III)and Pd(II)chelates as studied byoptically detected magnetic resonance techniques[J].Top.Curr.Chem.,2001,213:96.
[15] Komada Y,Yamauchi S,Hirota N.Phosphorescence and zero-field optically detected magnetic resonance stud-ies of the lowest excited triplet states of organometallic diimine complexes.1.Rhodium bipyridine and rhodiumphenanthroline complexes [Rh(bpy)₃] ³⁺ and [Rh(phen)₃] ³⁺[J].J.Phys.Chem.,1986,90:6425.
[16] Yersin H,Donges D,Nagle J K,Sitters R,Glasbeek M.Intra-ligand charge transfer in the Pd(II)oxinatecomplex Pd(qol)2Site-selective emission,excitation,and optically detected magnetic resonance[J].Inorg.Chem.,2000,39:770.
[17] Donges D,Nagle J K,Yersin H.Intra-ligand charge transfer in Pt(qol)2,characterization of electronic statesby high-resolution Shpol'skii Spectroscopy[J].Inorg.Chem.,1997,36:3040.
[18] Czerwieniec R,Strasser A,Starukhin A,Hofbeck T,Wedel A,Finkenzeller W,Yersin H.This work waspresented at the SPIE optics and photonics,Conference 5937,San Diego(USA),August,2005.
[19] Hay P J.Theoretical studies of the ground and excited electronic states in cyclo-metalated phenylpyridine Ir(III)complexes using density functional theory[J].J.Phys.Chem.A,2002,106:1634.
[20] Abedin-Siddique Z,Yamamoto Y,Ohno T,Nozaki K.Structure-dependent photo-physical properties of singletand triplet metal-to-ligand charge transfer states in Copper(I)bis(diimine)compounds.[J].Inorg.Chem.,2003,42:6366.
[21] Pierloot K,Ceulemans A,Merch n M,Serrano-Andr s L.Electronic spectra of the cyclometalated complexesM(2-thienylpyridine)2with M=Pd,Pt:a theoretical study[J].J.Phys.Chem.A,2000,104:4374.
[22] Abedin-Siddique Z,Ohno T,Nozaki K,Tsubomura T.Intense fluorescence of metal-to-ligand charge transferin[Pt(0)(binap)2] [binap=2,2-′Bis(diphenylphosphino)-1,1-′binaphthyl] [J].Inorg.Chem.,2004,43:663.
[23] Yutaka T,Obara S,Ogawa S,Nozaki K,Ikeda N,Ohno T,Ishii Y,Sakai K,Haga M.Syntheses and prop-erties of emissive iridium(III)complexes with tridentate benzimidazole derivatives[J].Inorg.Chem.,2005,44:4737.
[24] Miki H,Shimada M,Azumi T,Brozik J A,Crosby G A.Effect of the ligand-field strength on the radiativeproperties of the ligand-localized 3.pi..pi.*state of rhodium complexes with 1,10-phenanthroline:proposedrole of dd states[J].J.Phys.Chem.,1993,97:11175.
[25] Schmidt J,Wiedenhofer H,A von Zelewsky,Yersin H.Time-resolved vibrational structures of the tripletsublevel emission of Pd(2-thpy)2[J].J.Phys.Chem.,1995,99:226.
[26] Finkenzeller W J,Yersin H.Emission of Ir(ppy)3.temperature dependence,decay dynamics,and magneticfield properties[J].Chem.Phys.Lett.,2003,377:299.
[27] Finkenzeller W J,Stoessel P,Yersin H.Emission and absorption of Ir(ppy)2(CO)(Cl)-temperature depend-ence,phosphorescence decay dynamics,and assignments of excited states[J].Chem.Phys.Lett.,2004,397:289.
[28] Ceulemans A,Vanquickenborne L G.Charge-transfer spectra of iron(II)-and ruthenium(II)-tris(2,2'-bipyri-dyl)complexes[J].J.Am.Chem.Soc.,1981,103:2238.
[29] Finkenzeller W J,Yersin H.Emission of Ir(ppy)3.Temperature dependence,decay dynamics,and magneticfield properties.Chem.Phys.Lett.,2003,337:299.
[30] Yersin H,Humbs W,Strasser J.Characterization of excited electronic and vibronic states of platinum metalcompounds with chelate ligands by highly frequency-resolved and time-resolved spectra.Electronic and Vibron-ic Spectra of Transition Metal Complexes,Vol.II Springer-Verlag Berlin,ed.Yersin H.,Top.Curr.Chem.1997,191:153.
[31] Obara S,Itabashi M,Okuda F,Tamaki S,Tanabe Y,Ishii Y,Nozaki K,Haga M.Highly phosphorescent i-ridium complexes containing both tridentate bis(benzimidazolyl)-benzene or-pyridine and bidentate phenylpyri-dine:synthesis,photophysical properties,and theoretical study of Ir-bis(benzimidazolyl)benzene complex[J].Inorg.Chem.,2006,45:8907.
[32] Rebane K K.in:Sild O,Haller K(Eds.).Zero-Phonon Lines and Spectral Hole Burning in Spectroscopy andPhotochemistry[M].Berlin:Springer,1988.
[33] Alshitz E I,Personov R I,Kharlamov B M.Zero-field line splitting in the fluorescence spectra of complex mole-cules[J].Pisma Zh.Eksp.Teor.Fiz.,1977,26:751.
[34] Finkenzeller W J,Hofbeck T,Thompson M E,Yersin H.Triplet state properties of the OLED emitterIr(btp)(2)(acac):characterization by site-selective spectroscopy and application of high magnetic fields[J].Inorg.Chem.,2007,46:5076.
[35] Kohler A,Bassler H.Triplet states in organic semiconductor[J].Materials Science and Engineering,2009,71:R66.