MSA  Vol.4 No.4 , April 2013
Enhancement of Performance of Organic Light Emitting Diodes by Using Ti- and Mo-Oxide Nano Hybrid Layers
ABSTRACT

Nanorod-like TiO2 (nc-TiO2) and MoO3 (nc-MoO3) films were thermally grown from Ti- and Mo-metallic wafers. Nanohybrid films of N,N’-diphenyl-N,N’-bis(1-naphthyl)(1,1’-biphenyl)-4,4’diamine (NPB)/TiO2 and NPB/MoO3 used as anode/hole transport layer (HTL) heterojunctions in blue organic light emission diodes (OLEDs) were prepared by coating NPB onto the nc-TiO2 and nc-MoO3 and TiO2. Characterization of the nanostructured hybrid layers showed that both the photoluminescent property and current-voltage (I-V) characteristics of the hybrid materials were significantly enhanced in comparison with the standard NPB polymer. The electroluminous efficiency of the hybrid devices was considerably enhanced in comparison with the standard device. This suggests a useful application for fabricating “reverse” OLEDs, where the emission light goes-out through the semitransparent cathode, instead of the indium tin oxide (ITO) anode. For this, the ohmic contacts of conducting wires to metallic electrodes can be made much better than to ITO anodes.


Cite this paper
N. Dinh, D. Chung, T. Thao, T. Thuy, L. Chi and V. Truong, "Enhancement of Performance of Organic Light Emitting Diodes by Using Ti- and Mo-Oxide Nano Hybrid Layers," Materials Sciences and Applications, Vol. 4 No. 4, 2013, pp. 275-280. doi: 10.4236/msa.2013.44034.
References
[1]   J. S. Salafsky, “Exciton Dissociation, Charge Transport, and Recombination in Ultrathin, Conjugated Polymer, TiO2 Nanocrystal Intermixed Composites,” Physical Review B, Vol. 59, No. 16, 1999, pp. 10885-10894. doi:10.1103/PhysRevB.59.10885

[2]   W. U. Huynh, J. J. Dittmer and A. P. Alivisatos, “Hybrid Nanorod, Polymer Solar Cells,” Science, Vol. 295, No. 5564, 2002, pp. 2425-2427. doi:10.1126/science.1069156

[3]   J. Dittmer, R. Lazzaroni, P. Leclere, P. Moretti, M. Granstrom, K. Petritsch, E. A. Marseglia, R. H. Friend, J. L. Bredas, H. Rost and A. B. Holmes, “Crystal Network Formation in Organic Solar Cells,” Solar Energy Materials and Solar Cells, Vol. 61, 2000, pp. 53-61. doi:10.1016/S0927-0248(99)00096-3

[4]   V. M. Burlakov, K. Kawata, H. E. Assender, G. A. D. Briggs, A. Ruseckas and I. D. W. Samuel, “Discrete Hopping Model of Exciton Transport in Disordered Media,” Physical Review B, Vol. 72, No. 7, 2005, Article ID: 075206. doi:10.1103/PhysRevB.72.075206

[5]   P. S. Thomas, J. Kuruvilla and T. Sabu, “Mechanical Properties of Titanium Dioxide-Filled Polystyrene Microcomposites,” Materials Letters, Vol. 58, No. 3-4, 2004, pp. 281-289. doi:10.1016/S0167-577X(03)00470-1

[6]   S. A. Choulis, M. K. Mathai and V.-E. Choong, “Influence of Metallic Nanoparticles on the Performance of Organic Electrophosphorescence Devices,” Applied Physics Letters, Vol. 88, No. 21, 2006, Article ID: 213503. doi:10.1063/1.2200285

[7]   S. A. Carter, J. C. Scott and J. Brock, “Enhanced Luminance in Polymer Composite Light Emitting Diodes,” Applied Physics Letters, Vol. 71, No. 9, 1997, pp. 1145-1147. doi:10.1063/1.119848

[8]   A. Petrella, M. Tamborra, P. D. Cozzoli, M. L. Curri, M. Striccoli, P. Cosma, G. M. Farinola, F. Babudri, F. Naso and A. Agostiano, “TiO2 Nanocrystals—MEH-PPV Composite Thin Films as Photoactive Material,” Thin Solid Films, Vol. 451-452, 2004, pp. 64-68. doi:10.1016/j.tsf.2003.10.106

[9]   A. A. Madhavan, G. G. Kumar, S. Kalluri, J. Joseph, S. Nagarajan, S. Nair, K. R. V. Subramanian and A. Balakrishnan, “Effect of Embedded Plasmonic Au Nanoparticles on Photocatalysis of Electrospun TiO2 Nanofibers,” Journal of Nanoscience and Nanotechnology, Vol. 12, No. 10, 2012, pp. 7963-7967. doi:10.1166/jnn.2012.6492

[10]   K. J. Klabunde, “Nanoscale Materials in Chemistry,” John Wiley & Sons, Hoboken, 2001. doi:10.1002/0471220620

[11]   R. Nirmala, J. W. Jeong, R. Navamathavan and H. Y. Kim, “Synthesis and Electrical Properties of TiO2 Nanoparticles Embedded in Polyamide-6 Nanofibers via Electrospinning,” Nano-Micro Letters, Vol. 3, No. 1, 2011, pp. 56-61.

[12]   N. N. Dinh, L. H. Chi, T. T. Chung-Thuy, T. Q. Trung and Vo-Van Truong, “Enhancement of Current-Voltage Characteristics of Multilayer Organic Light Emitting Diods by Using Nanostructured Composite Films,” Journal of Applied Physics, Vol. 105, 2009, pp. 093518-1-093518-5.

[13]   T. T. Chung-Thuy, L. H. Chi and N. N. Dinh, “Study of Photoluminescent and Electrical Properties of Nanostructured MEH-PPV/TiO2 Hybrid Films,” JKPS, Vol. 54, 2009, pp. 291-295. doi:10.3938/jkps.54.291

[14]   B. D. Cullity, “Elements of X-Ray Diffraction,” 2nd Edition, Addison-Wesley Publishing Company, Boston, 1978,

[15]   Y. T. Lin, T. W Zeng, W. Z. Lai, C. W. Chen, Y. Y. Lin, Y. S. Chang and W. F. Su, “Efficient Photoinduced Charge Transfer in TiO2 Nano-Rod/Conjugated Polymer Hybrid Materials,” Nanotechnology, Vol. 17, No. 23, 2006, pp. 5781-5785. doi:10.1088/0957-4484/17/23/012

[16]   S. H. Yang, T. P. Nguyen, P. Le Rendu and C. S. Hsu, “Optical and Electrical Properties of PPV/SiO2 and PPV/ TiO2 Composite Materials,” Composites Part A: Applied Science and Manufacturing, Vol. 36, No. 4, 2005, pp. 509-513. doi:10.1016/j.compositesa.2004.10.008

[17]   G. Heliotis, G. Itskos, R. Murray, M. D. Daw-Son, I. M. Watson and D. D. C. Bradley, “Hybrid Inorganic/Organic Semiconductor Heterostructures with Efficient Non-Radiative Energy Transfer,” Advanced Materials, Vol. 18, No. 3, 2006, pp. 334-338. doi:10.1002/adma.200501949

[18]   Z. Chen, I. Santoso, R. Wang, L. F. Xie, H. Y. Mao, H. Huang, Y. Z. Wang, X. Y. Gao, Z. K. Chen, D. Ma, A. T. S. Wee and W. Chen, “Surface Transfer Hole Doping of Epitaxial Graphene Using MoO3 Thin Film,” Applied Physics Letters, Vol. 96, No. 21, 2010, pp. 213104-213107. doi:10.1063/1.3441263

[19]   S. Gutmann, M. A. Wolak, M. Conrad, M. M. Beerbom and R. Schlaf, “Effect of Ultraviolet and X-Ray Radiation on the Work Function of TiO2 surfaces,” Journal of Applied Physics, Vol. 107, No. 10, 2010, pp. 103705-103708. doi:10.1063/1.3410677

[20]   R. Schlaf, H. Murata and Z. H. Kafafi, “Work Function Measurements on Indium Tin Oxide Films,” Journal of Electron Spectroscopy and Related Phenomena, Vol. 120, No. 1-3, 2001, pp. 149-154. doi:10.1016/S0368-2048(01)00310-3

 
 
Top