D. I. Mendeleeev Russian University of Chemical Technology, *National University of Science and Technology «MISIS»:

R. I. Avetisov

O. B. Petrova

A. A. Akkuzina

A. V. Khomyakov

R. R. Saifutyarov

A. G. Cherednichenko

T. B. Sagalova
N. A. Makarov

I. Ch. Avetissov

We studied regularities of polymorphous transitions in high−purity powder preparations of metal complex of 8−hydroxyquinoline with aluminum, gallium and indium (Meq₃, where Me= Al, Ga, In) in the 300−712 K temperature range. According to the results of luminescent and Raman spectra measurements combined with XRD analysis, the general pattern of the polymorphous transitions in all the investigated compounds is β → α→ δ→ γ → ε. Hybrid materials (HM) were synthesized based on borate glass matrix with 0.02–0.1 wt % Meq3. Bulk samples were obtained by melting, and HM thin films were produced by high vacuum deposition. The luminescent properties of the hybrid materials were studied at room temperature. For the bulk HM an increase in the synthesis duration resulted in the shift of the maximum luminescence peak towards short wavelengths relative to that of pure δ(γ)−Meq₃ by 40 nm for Alq₃, 15 nm for Gaq₃, and 10 nm for Inq₃.

1. Physics of Organic Semiconductors / Ed. by W. Britting. − Weinheim: WILEY−VCH Verlag GmbH & Co. KGaA, 2005.
2. Troshin, P. A. Funkcional’nye proizvodnye fullerenov: metody sinteza i perspektivy ispol’zovaniya v organicheskoi elektronike i biomedicine / P. A. Troshin, O. A. Troshina, R. N. Lyubovskaya, V. F. Razumov — Ivanovo : Ivan. gos. un−t, 2010. − 340 s.
3. Sanz, N. Organic nanocrystals embedded in sol−gel glasses for optical applications/ N. Sanz, P. L. Baldeck, A. Ibanez // Synth. Met. − 2000. − V. 115, Iss. 1−3. − P. 229—234.
4. Hironori, Kaji. Relationships between light−emitting properties and different isomers in polymorphsof tris(8−hydroxyquinoline) aluminum(III) (Alq₃) analyzed by solid−state 27Al NMR and density functional theory (DFT) calculations / Hironori Kaji, Yasunari Kusaka, Goro Onoyama, Fumitaka Horii // Jap. J. Appl. Phys. − 2005. − V. 44 − P. 3706—3711.
5. Rajeswaran, M. Structural, thermal and spectral characterization of the different crystalline forms of Alq₃, tris(quinolin−8−olato) aluminum(III), an electroluminescent material in OLED technology / M. Rajeswaran, T. N. Blanton, C. W. Tang, W. C. Lenhart, S. C. Switalski, D. J. Giesen, B. J. Antalek, T. D. Pawlik, D. Y. Kondakov, N. Zumbulyadis, R. H. Young // Polyhedron. − 2009. − V. 28. − P. 835—843.
6. Tsuboi, T. Selective synthesis of facial and meridianal isomers of Alq₃ / T. Tsuboi, Y. Torii // Mol. Cryst. Lig. Cryst. − 2010. − V. 529. − P. 42—52.
7. Sakurai, Y. Study of the interaction of tris−(8−hydroxyquinoline) aluminum (Alq₃) with potassium using vibrational spectroscopy: Examination of possible isomerization upon K doping / Y. Sakurai, Y. Hosoi, H. Ishii, Y. Ouch // J. Appl. Phys. − 2004. − V. 96. − P. 534—554.
8. Xua, B. Preparation and performance of a new type of blue light−emitting material δ−Alq₃ / Bingshe Xua, Hua Wang, Yuying Hao, Zhixiang Gao, Hefeng Zhou //J. Luminescence. − 2007. − V. 122−123. − P. 663—666.
9. Fukushima, T. Green− and blue−emitting tris(8−hydroxyquinoline) aluminum(III) (Alq₃) crystalline polymorphs: Preparation and application to organic light−emitting diodes / T. Fukushima, H. Kaji // Organic Electronics. − 2012. − V. 13. − P. 2985—2990.
10. Brinkmann, M. Correlation between molecular packing and optical properties in different crystalline polymorphs and amorphous thin films of mer−tris(8−hydroxyquinoline)aluminum(III) / M. Brinkmann, G. Gadret, M. Muccini, C. Taliani, N. Masciocchi, A. Sironi // J. Amer. Chem. Soc. − 2000. − V. 122. − P. 5147—5157.
11. Brinkmann, M. Structure and spectroscopic properties of the crystalline structures containing meridional and facial isomers of tris(8−hydroxyquinoline)gallium(III) / M. Brinkmann, B. Fite, S. Pratontep, C. Chaumont // Chem. Mater. − 2004. − V. 16. − P. 4627—4633.
12. Sapochak, L. S. Structure and three−dimensional crystal packing preferences for mer−tris(8−quinolinolato)indium(III) vapor−phase−grown crystals / L. S. Sapochak, A. Ranasinghe, H. Kohlmann, K. F. Ferris, P. E. Burrows // Chem. Mater. − 2004. − V. 16 − P. 401—406.
13. Organic electronics: materials, processing, devices and applications / Ed. by S. Franky. − Boca Raton ; London ; N−Y. : Taylor and Francis Group, 2010. − 582 p.