Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-28T02:28:02.810Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystallization properties of IrQ(ppy)2 organometallic complex films

Published online by Cambridge University Press:  02 May 2017

Silviu Polosan ,
Constantin Claudiu Ciobotaru ,
Iulia Corina Ciobotaru  and
Taiju Tsuboi
Silviu Polosan*
Affiliation:
National Institute of Materials Physics, Bucharest-Magurele R-77125, Romania
Constantin Claudiu Ciobotaru
Affiliation:
National Institute of Materials Physics, Bucharest-Magurele R-77125, Romania
Iulia Corina Ciobotaru
Affiliation:
National Institute of Materials Physics, Bucharest-Magurele R-77125, Romania
Taiju Tsuboi
Affiliation:
Kyoto Sangyo University, Kyoto 603-8555, Japan
*
a) Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Comparative studies between doped conducting polymers and electrochemical deposited organometallic compounds reveals the interplay between crystalline-amorphous phases with significant contributions to the internal quantum efficiency in the OLED devices. The coexistence of the amorphous and crystalline phase in the electrodeposited film is revealed by the minor micro-crystal products which are present in the amorphous phase in thin films, while the many micro-crystals are randomly distributed in the thick films. Concerning the doped conducting polymers, the level of doping induces crystalline effects as a result of the π–π stacking between molecules, due to the Forester energy transfer processes in which the transfer rate is increased with decreasing of the distances between neighboring molecules. The crystallization processes change the emission properties of the active layers both for the luminance level and all over color, ranging from yellow to red in the case of IrQ(ppy)2 compounds.

Keywords

organometallicthin filmelectrodeposition
Type
Articles
Information
Journal of Materials Research , Volume 32 , Issue 9 , 15 May 2017 , pp. 1735 - 1740
Check for updates
Copyright
Copyright © Materials Research Society 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Contributing Editor: Tao Xie

References

REFERENCES

Tang, C.W. and Van Slyke, S.A.: Organic electroluminescent diodes. Appl. Phys. Lett. 51, 913 (1987).Google Scholar
Wang, G., Wong, T.K.S., and Hu, X.: Influence of thickness of electrochemically deposited hole-transport film on electroluminescent properties. Appl. Phys. A 71, 117 (2000).Google Scholar
Lincot, D.: Electrodeposition of semiconductors. Thin Solid Films 487, 40 (2005).Google Scholar
Kathalingam, A., Kim, M.R., Chae, Y.S., Rhee, J.K., and Mahalingam, T.: Studies on electrochemically deposited ZnO thin films. J. Korean Phys. Soc. 55, 2476 (2009).Google Scholar
Damlin, P., Gstergard, T., Ivaska, A., and Stubb, H.: Light-emitting diodes of poly(p-phenylene vinylene) films electrochemically polymerized by cyclic voltammetry on IT0. Synth. Met. 102, 947 (1999).Google Scholar
Chang, W., Whang, W., and Lin, P.: Characteristics of an electropolymerized PPV and its light-emitting diode. Polymer 37, 1513 (1996).Google Scholar
Li, M., Li, M., Tang, S., Shen, F., Liu, M., Li, F., Lu, P., Lu, D., Hanif, M., and Ma, Y.: The counter anionic size effects on electrochemical, morphological, and luminescence properties of electrochemically deposited luminescent films. J. Electrochem. Soc. 155, H287 (2008).Google Scholar
Ostergard, T., Kvarnstrom, C., Stubb, H., and Ivaska, A.: Electrochemically prepared light-emitting diodes of poly(para-phenylene). Thin Solid Films 311, 58 (1997).Google Scholar
Zhu, Y., Gu, C., Tang, S., Fei, T., Gu, X., Wang, H., Wang, Z., Wang, F., Lu, D., and Ma, Y.: A new kind of peripheral carbazole substituted ruthenium(II) complexes for electrochemical deposition organic light-emitting diodes. J. Mater. Chem. 19, 3941 (2009).Google Scholar
Li, M., Tang, S., Shen, F., Liu, M., Wang, H., Lu, P., Hanif, M., and Ma, Y.: Electrochemical deposition of patterning and highly luminescent organic films for light emitting diodes. Semicond. Sci. Technol. 22, 855 (2007).Google Scholar
Li, M., Tang, S., Shen, F., Liu, M., Xie, W., Xia, H., Liu, L., Tian, L., Xie, Z., Lu, P., Hanif, M., Lu, D., Cheng, G., and Ma, Y.: Highly luminescent network films from electrochemical deposition of peripheral carbazole functionalized fluorene oligomer and their applications for light-emitting diodes. Chem. Commun. 32, 3393 (2006).CrossRefGoogle Scholar
Li, M., Tang, S., Shen, F., Xie, W., Xia, H., Liu, L., Tian, L., Xie, Z., Hanif, M., Lu, D., Cheng, G., and Ma, Y.: Electrochemically deposited organic luminescent films: The effects of deposition parameters on morphologies and luminescent efficiency of films. J. Phys. Chem. B 110, 17784 (2006).Google Scholar
Gu, C., Tang, S., Yang, B., Liu, S., Wang, H., Yang, S., Hanif, M., Lu, D., Shen, F., and Ma, Y.: Almost completely dedoped electrochemically deposited luminescent films exhibiting excellent LED performance. Electrochim. Acta 54, 7006 (2009).CrossRefGoogle Scholar
Liu, C., Luo, H., Shi, G., Yang, J., Chi, Z., and Ma, Y.: Luminescent network film deposited electrochemically from a carbazole functionalized AIE molecule and its application for OLEDs. J. Mater. Chem. C 3, 3752 (2015).Google Scholar
Sun, C.J., Wu, Y., Xu, Z., Hu, B., Bai, J., Wang, J.P., and Shen, J.: Enhancement of quantum efficiency of organic light emitting devices by doping magnetic nanoparticles. Appl. Phys. Lett. 90, 232110 (2007).Google Scholar
Ciobotaru, I.C., Polosan, S., and Ciobotaru, C.C.: Dual emitter IrQ(ppy)2 for OLED applications: Synthesis and spectroscopic analysis. J. Lumin. 145, 259 (2014).Google Scholar
Garnier, F.: Thin film transistors based on organic conjugated semiconductors. Chem. Phys. 282, 253 (1998).Google Scholar
Katz, H.E., Dodabalapur, A., and Bao, Z.: Oligo- and Polythiophene-based Field-effect Transistors, Fichou, D., ed. (Wiley-VCH, Weinheim, 1998).Google Scholar
Hotta, S. and Waragai, K.: Organic molecular solids as thin film transistor semiconductors. Adv. Mater. 5, 896 (1993).CrossRefGoogle Scholar
Nelson, S.F., Lin, Y-Y., Gundlach, D.J., and Jackson, T.N.: Temperature-independent transport in high-mobility pentacene transistors. Appl. Phys. Lett. 72, 1854 (1998).Google Scholar
Horowitz, G., Hajlaoui, R., Fichou, D., and El Kassmi, A.: Field-effect transistors based on short organic molecules. J. Appl. Phys. 85, 3202 (1999).Google Scholar
Hajlaoui, R., Fichou, D., Horowitz, G., Nessakh, B., Constant, M., and Garnier, F.: Organic transistors using α-octithiophene and α, ω-dihexyl-α-octithiophene: Influence of oligomer length versus molecular ordering on mobility. Adv. Mater. 9, 557 (1997).CrossRefGoogle Scholar
Polosan, S., Ciobotaru, I.C., and Tsuboi, T.: Absorption, phosphorescence and Raman spectra of IrQ(ppy)2 organometallic compound. Mater. Chem. Phys. 162, 822–830 (2015).Google Scholar
Yi, C., Yang, C., Liu, J., Xu, M., Wang, J., Cao, Q., and Gao, X.: Red to near-infrared electrophosphorescence from an iridium complex coordinated with 2-phenylpyridine and 8-hydroxyquinoline. Inorg. Chim. Acta 360, 3493 (2007).Google Scholar
Kappaun, S., Eder, S., Sax, S., Mereiter, K., and Slugovc, C.: Organoiridium quinolinolate complexes: Synthesis, structures, thermal stabilities and photophysical properties. Eur. J. Inorg. Chem. 26, 4207 (2007).Google Scholar
Rivnay, J., Mannsfeld, S.C.B., Miller, C.E., Salleo, A., and Toney, M.F.: Determination of organic semiconductor microstructure from the molecular to device scale. Chem. Rev. 112, 5488 (2012).Google Scholar
Ding, J., Gao, J., Fu, Q., Cheng, Y., Ma, D., and Wang, L.: Highly efficient phosphorescent bis-cyclometalated iridium complexes based on quinoline ligands. Synth. Met. 155, 539 (2005).Google Scholar
You, Y. and Park, S.Y.: Inter-ligand energy transfer and related emission change in the cyclometalated heteroleptic iridium complex: Facile and efficient color tuning over the whole visible range by the ancillary ligand structure. J. Am. Chem. Soc. 127, 12438 (2005).Google Scholar
Holmes, R.J., Forrest, S.R., Tung, Y.J., Kwong, R.C., Brown, J.J., Garon, S., and Thompson, M.E.: Blue organic electrophosphorescence using exothermic host–guest energy transfer. Appl. Phys. Lett. 82(15), 2422 (2003).Google Scholar
Dale, R.E., Eisinger, J., and Blumberg, W.E.: The orientational freedom of molecular probes. The orientation factor in intramolecular energy transfer. Biophys. J. 26, 161 (1979).Google Scholar
Mersol, J.V., Wang, H., Gafni, A., and Steel, D.G.: Consideration of dipole orientation angles yields accurate rate equations for energy transfer in the rapid diffusion limit. Biophys. J. 61, 1647 (1992).Google Scholar
Pommerehne, J., Vestweber, H., Guss, W., Mahrt, R.F., Bassler, H., Proseh, M., and Daub, J.: Efficient two layer leds on a polymer blend basis. Adv. Mater. 7(6), 551 (1995).Google Scholar