The triplet state in tris-(8-hydroxyquinoline)aluminum

This paper presents the characterization of the triplet state in tris-(8-hydroxyquinoline)aluminum (Alq3). An emission spectrum of Alq3, namely, the phosphorescence, is presented for crystalline and amorphous Alq3, which enables direct investigation of the T1→S0 transition. The assignment of this spectrum to the phosphorescence is further confirmed by temperature-dependent measurements and comparison with the delayed fluorescence. The triplet energies of the meridional and facial isomer (in α- and δ-Alq3) are determined from the well-resolved vibronic progressions of the phosphorescence as 2.11±0.1 and 2.16±0.1eV, respectively. Furthermore, the lifetime of the triplet state is measured for a temperature range from 6to150K. These temperature-dependent measurements also identify a so far unknown phase transition of Alq3 at about 50K. Optically detected magnetic resonance at a zero field is used to measure the characteristic zero-field splitting parameters (∣E∣=0.0114cm−1 and ∣D∣=0.0630cm−1), and these are d...

[1]  Hong Zhang,et al.  Femtosecond fluorescence upconversion spectroscopy of vapor-deposited tris(8-hydroxyquinoline) aluminum films. , 2000 .

[2]  M. Cölle,et al.  Preparation and Characterization of Blue‐Luminescent Tris(8‐hydroxyquinoline)‐aluminum (Alq3) , 2003 .

[3]  T. Blanton,et al.  Refinement of the crystal structure of the δ-modification of tris(8-hydroxyquinoline) aluminum(III), δ-Al(C9H6NO)3, the blue luminescent Alq3 , 2003 .

[4]  W. Gillin,et al.  Morphological study of aluminum tris(8-hydroxyquinoline) thin films using infrared and Raman spectroscopy , 2002 .

[5]  F. Lelj,et al.  Are UV-Vis and luminescence spectra of Alq3 [aluminum tris(8-hydroxy quinolinate)] δ-phase compatible with the presence of the fac-Alq3 isomer? A TD-DFT investigation , 2002 .

[6]  M. Kinoshita,et al.  Molecular Spectroscopy of the Triplet State through Optical Detection of Zero-Field Magnetic Resonance , 1981 .

[7]  B. S. Basak,et al.  Crystal and molecular structure of 8‐hydroxyquinoline , 1978 .

[8]  H. Wolf,et al.  ESR-Untersuchungen an Triplett-Excitonen in Anthracen- und Naphthalin-Einkristallen , 1970 .

[9]  H. Wolf,et al.  Elektronenspin‐Resonanz von Triplett‐Exzitonen in Anthrazen , 1967 .

[10]  Michele Muccini,et al.  Correlation between Molecular Packing and Optical Properties in Different Crystalline Polymorphs and Amorphous Thin Films of mer-Tris(8-hydroxyquinoline)aluminum(III) , 2000 .

[11]  Richard L. Martin,et al.  Molecular and solid-state properties of tris-(8-hydroxyquinolate)-aluminum , 2000 .

[12]  Charles E. Swenberg,et al.  Electronic Processes in Organic Crystals and Polymers , 1999 .

[13]  R. Dinnebier,et al.  The structure of the blue luminescent ??-phase of tris(8-hydroxyquinoline)aluminium(iii) (Alq3)Electronic supplementary information (ESI) available: experimental section and crystallographic data. See http://www.rsc.org/suppdata/cc/b2/b209164j/ , 2002 .

[14]  C. H. Chen,et al.  Electroluminescence of doped organic thin films , 1989 .

[15]  M. Cölle,et al.  Phosphorescence of aluminum tris(quinoline-8-olate) , 2004 .

[16]  I. Akai,et al.  PHOTOLUMINESCENCE AND DYNAMICS OF EXCITONS IN Alq3 SINGLE CRYSTALS , 2001 .

[17]  Jan F. Schmidt,et al.  Spin-forbidden radiationless processes in isoelectronic molecules: Anthracene, acridine and phenazine , 1974 .

[18]  M. Cölle,et al.  Vibrational analysis of different crystalline phases of the organic electroluminescent material aluminium tris(quinoline-8-olate)(Alq3) , 2003 .

[19]  F. Papadimitrakopoulos,et al.  Characterization of isomers in aluminum tris(quinoline-8-olate) by one-dimensional 27Al nuclear magnetic resonance under magic-angle spinning , 2003 .

[20]  K. C. Kao,et al.  Electrical Transport in Solids , 1983 .

[21]  H. Wolf,et al.  ESR-Untersuchungen an Naphthalin-d8: Naphthalin-h8-Mischkristallen in deren Triplett-Zustand , 1967 .

[22]  K. Obata,et al.  Fluorescence Lifetime of Organic Thin Films Alternately Deposited with Diamine Derivative and Aluminum Quinoline , 1997 .

[23]  W. Brütting,et al.  A new crystalline phase of the electroluminescent material tris(8-hydroxyquinoline) aluminum exhibiting blueshifted fluorescence , 2001 .

[24]  Richard Haight,et al.  Unoccupied molecular orbital states of tris (8-hydroxy quinoline) aluminum: Observation and dynamics , 1997 .

[25]  Wolfgang Brütting,et al.  Device physics of organic light-emitting diodes based on molecular materials , 2001 .

[26]  J. Hayes,et al.  Microwave-induced triplet-triplet absorption in organic molecules , 1973 .

[27]  Stephen R. Forrest,et al.  Relationship between electroluminescence and current transport in organic heterojunction light‐emitting devices , 1996 .

[28]  D. Jennings,et al.  Study of Anthracene Fluorescence Excited by the Ruby Giant-Pulse Laser , 1963 .

[29]  M. Cölle,et al.  Thermal, structural and photophysical properties of the organic semiconductor Alq3 , 2004 .

[30]  Stephen R. Forrest,et al.  Transient analysis of organic electrophosphorescence: I. Transient analysis of triplet energy transfer , 2000 .

[31]  Andreas Elschner,et al.  Surface roughness effects and their influence on the degradation of organic light emitting devices , 2000 .

[32]  M. Fernandes,et al.  Characterization of the triplet state of tris(8-hydroxyquinoline)aluminium(III) in benzene solution. , 2003, Journal of the American Chemical Society.