Publications

Organic Optoelectronic Materials & Devices Laboratory��

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PUBLICATIONS

2008

� Y. Lou, H. Aziz, G. Xu, Z. Popovic, and G. Xu �Effect of exciton diffusion on electroluminescence of organic light emitting devices�, Organic Electronics 9, 1128 (2008).

� R.A. Klenkler, H. Aziz, A. Tran, Z. Popovic, and G. Xu �High electron mobility triazine for lower driving voltage and higher efficiency organic light emitting devices�, Organic Electronics 9, 285 (2008).

� Y.C. Luo, H. Aziz, R. Klenkler, G. Xu, and Z. Popovic, �Temperature dependence of photoluminescence efficiency in doped and blended organic thin films� Chemical Physics Letters 458, 319 (2008).

� T. Sadek, H. Aziz, R.O.� Loutfy, R.O. and P.M. Smith, P.M, �Poor confinement of e-h recombination zone in blue OLEDs� Proceedings of the IEEE Canadian Conference on Electrical and Computer Engineering, Niagara Falls, Ontario, May 2008, Pp 1117-1120 (2008).

2007

� Y.C. Luo, H. Aziz, Z.D. Popovic and G. Xu, �Electron induced quenching of excitons in luminescent materials �, Chem. Mat. 19, 2288 (2007).�

� Y.C. Luo, H. Aziz, G. Xu, and Z.D. Popovic �Similar roles of electrons and holes in the degradation of organic light-emitting devices�, Chem. Mat. 19, 2079 (2007).�

� Y.C. Luo, H. Aziz, Z.D. Popovic and G. Xu, �Improving the stability of organic light-emitting devices by using a hole-injection-tunable-anode-buffer-layer� J. Appl. Phys. 101, 054512 (2007).

� Y.C. Luo, H. Aziz, Z.D. Popovic and G. Xu, �Degradation mechanisms in organic light-emitting devices: metal migration model versus unstable tris(8-hydroxyquinoline) aluminum cationic model� J. Appl. Phys. 101, 034510 (2007).

2006

� H. Aziz, Y. Luo, G. Xu, Z.D. Popovic, �Improving the Stability of Organic Light-Emitting Devices by Using a Thin Mg Anode Buffer Layer�� Applied Physics Letters 89, 103515 (2006).

� Y. Luo, H. Aziz, Z.D. Popovic, G. Xu, �Electric-field-induced Fluorescence Quenching in Dye-doped Tris(8-hydroxyquinoline) Aluminum Layers� Applied Physics Letters 89, 103505 (2006).

� R. Klenkler, G. Xu, H. Aziz, Z.D. Popovic �Charge-carrier Mobility in an Organic Semiconductor Thin Film Measured by Photoinduced Electroluminescence� Applied Physics Letters 88, 242101 (2006).

� Y. Luo, H. Aziz,� G. Xu, and Z. D. Popovic �Effect of Driving Mode on Electroluminescence Efficiency and Stability of Organic Light-Emitting Devices� Journal of Applied� Physics 99, 054508 (2006).

� Y.C. Luo, H. Aziz, Z.D. Popovic and G. Xu, �Electric field and temperature dependence of photoluminescence in fluorescent dye doped tris(8-hydroxyquinoline) aluminum�, Proceedings of the SPIE Conference on Organic Light Emitting Materials and Devices X, San Diego, CA, August 2006, Volume 6333 Pp 63331V (2006).

2005

� R. Wang, W. Jia, H. Aziz, G. Vamvounis, S. Wang, N. Hu, Z. D. Popovic, J. Coggan �1-Methyl-2-(Anthryl)-Imidazo[4,5-f] [1,10]-Phenanthroline: A Highly Efficient Electron Transport Compound and a Bright Blue Emitter for Electroluminescent Devices�, Advanced Functional Materials 15, 1483 (2005).

� Z. D. Popovic and H. Aziz, �Delayed Electroluminescence In Small Molecule Based Organic Light Emitting Diodes � Evidence For Triplet-Triplet Annihilation And Recombination Center Mediated Light Generation Mechanism�, Journal of Applied Physics 98, 13510 (2005).

� Z. D. Popovic and H. Aziz, �Delayed Electroluminescence: A New Tool for Studies of OLED Fundamental Properties�, Proceedings of the SPIE Conference on Organic Light Emitting Materials and Devices IX,�� San Diego CA, July 31-Aug.3, 2005, Volume 5937, Pp 126-132 (2005).

2004

� H. Aziz* and Z. D. Popovic, �Degradation Phenomena in Small-Molecule Organic Light Emitting Devices�, Chemistry of Materials 16, 4522 (2004).

� S.M. Tadayyon, H.M. Grandin, K. Griffiths, L.L. Coatsworth, P.R. Norton, H. Aziz and Z. D. Popovic, �Reliable and Reproducible Determination of Work Function and Ionization Potentials of Layers and Surfaces Relevant to Organic Light Emitting Diodes�, Organic Electronics 5, 199 (2004).

� S.M. Tadayyon, H.M. Grandin, K. Griffiths, P.R. Norton, H. Aziz and Z. D. Popovic, �CuPc Buffer Layer Role in OLED Performance: A Study of the Interfacial Band Enenrgies�, Organic Electronics 5, 157 (2004).

� G. Vamvounis, H. Aziz, N. Hu, and Z. D. Popovic �Temperature Dependence of Operational Stability of Organic Light Emitting Diodes Based on Mixed Emitter Layers�, Synthetic Metals 143, 69 (2004).

� S. Holdcroft, Y. Li, G. Vamvounis, H. Aziz, and Z. D. Popovic �Tuning Optical and Electroluminescent Properties of Poly(thiophene)e via Post-Functionalization�,� in �Chromogenic Phenomena in Polymers: Tunable Optical Properties� Edited by Samson A. Jenekhe and Douglas J. Kiserow, Oxford University Press, Sept 2004.

� H. Aziz, Y. Liew and Z.D. Popovic �Novel Cathode for Organic Light Emitting Devices with Reduced Optical Reflectivity� Proceedings of SPIE Conference on Organic Light Emitting Materials and Devices VII,� San Diego CA, Aug.3-6, 2003, Vol. 5214, Pp 277-282, (2004).

2003

� H. Aziz, Y. Liew,� H. M. Grandin and Z. Popovic �Reduced Reflectance Cathode For Organic Light Emitting Devices Using Metal-Organic Mixtures� ,� Applied Physics Letters� 83, 186 (2003).

� H. M. Grandin,� H. Aziz,*� S. Gardner,� C. Jennings,� A.J. Paine,� P.R. Norton, and� Z. D. Popovic� �Light Absorption Phenomena in Novel Low Reflectance Cathodes for Organic Light Emitting Devices Utilizing Metal-Organic Mixtures�, Advanced Materials 15, 2021 (2003).

� H.M. Grandin, S.M. Tadayyon, W.N. Lennard, K. Griffiths, L.L. Coatsworth, P.R. Norton, Z. Popovic, H. Aziz, and� N. Hu, �Rutherford backscattering and secondary ion mass spectrometry of silver-tris-(8-hydroxyquinoline) aluminum interfaces� Organic Electronics 4, 9 (2003).

� H. Aziz and Z.D. Popovic �Study of Organic Light Emitting Devices with� 5,6,11,12-tetraphenylnaphthacene (Rubrene)-doped Hole Transport Layer� Proceedings of SPIE Conference on Organic Light Emitting Materials and Devices VI,� Seatle WA, July 7-11, 2002, Vol. 4800, Pp 80-86, (2003).

� Z.D. Popovic, G. Vamvounis, H. Aziz, and N. Hu �OLEDs with enhanced high temperature operational stability�� Proceedings of SPIE Conference on Organic Light Emitting Materials and Devices VI,� Seatle WA, July 7-11, 2002, Vol. 4800, Pp 87-92, (2003).

2002

� H. Aziz and Z. Popovic, �Study of Organic Light Emitting Devices with� 5,6,11,12-tetraphenylnaphthacene (Rubrene)-doped Hole Transport Layer�, Applied Physics Letters� 80, 2180 (2002).

� H. Aziz, Z. Popovic and N. Hu, �Organic Light Emitting Devices with Enhanced Operational Stability at Elevated Temperatures�, Applied Physics Letters 81, 370 (2002).

� Turak, D. Grozea, X. D. Feng,� Z.H. Lu,� H. Aziz, and A. Hor,� �Metal/AlQ₃ Interface Structures�, Applied Physics Letters 81, 766 (2002).

� P.N.M. dos Anjos, H. Aziz, N. Hu, and Z. D. Popovic, �Temperature dependence of electroluminescence degradation in organic light emitting devices without and with a copper phthalocyanine buffer layer�, Organic Electronics� 3, 9 (2002).

� Z. Popovic and H. Aziz, �Reliability and Degradation of Small Molecule Organic Light Emitting Devices�,� IEEE Journal on Selected Topics in Quantum Electronics 8, 362, (2002).�

2001

� Z.D. Popovic, H. Aziz, N. Hu, A. Ioannidis, and P. N. M. dos Anjos, �Simultaneous electroluminescence and photoluminescence aging studies of tris(8-hydroxyquinoline) aluminum based organic light emitting devices� Journal of� Applied Physics 89, 4673 (2001).

� Z. Popovic, H. Aziz, A. Ioannidis, N. Hu and P.N.M. dos Anjos, �Time resolved fluorescence studies of AlQ₃-based organic light emitting devices� Synthetic Metals 123, 179 (2001).

� H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A-M. Hor and H. Aziz, �Surface electronic structure of plasma-treated indium tin oxides�, Applied Physics Letters 78, 2595 (2001).

� X. D. Feng, D. Grozea, A. Turak,� Z.H. Lu,� H. Aziz, and A.-M. Hor, �Studies Alq/Mg:Ag Interfaces in Organic Light-Emitting Diodes by XPS�� Proceedings of MRS Conference on Organic and Polymeric Materials and Devices � Optical, Electrical and Optoelectronic Properties, 2002, Vol. 725, Pp 31-36, (2002).

� H. Aziz, Z. Popovic, N.Hu, P. Dos Anjos and A. Ioannidis, �Degradation of tris(8-hydroxyquinoline) (ALQ3)-based organic light emitting devices (OLEDs)�� Proceedings of SPIE Conference on Organic Light Emitting Materials and Devices IV,� San Diego CA, July 30 � Aug.4, 2000, Vol. 4105, Pp 251-255, (2001).

2000

� Y. Liew, H. Aziz, N. Hu,H. Chan, G. Xu and Z. Popovic, �Investigation of the sites of dark spots in organic light-emitting devices� Applied Physics Letters� 77, 2650 (2000).

� S.-F. Liu, C. Seward, H. Aziz, N.-X. Hu, Z. Popovic and S. Wang, �Syntheses, structures, and luminescence/electroluminescence of BPh₂(mqp), Al(Ch₃)(mqp)₂, and Al(mqp)₃ (mqp=2-(4�-Methylquinolinyl)-2-phenolato�, Organometallics 19, 5709 (2000).

� Z. Popovic, H. Aziz, N. Hu, A. Hor, and G. Xu, �Long-term degradation mechanism of tris(8-hydroxyquinoline)-based organic light emitting devices�,� Synthetic Metals 111-112, 229 (2000).

� S. Liu, Q. Wu, H.L. Schmider, H. Aziz,� N. Hu, Z. Popovic, S. Wang, �Syntheses, structures, and electroluminescence of new blue/green luminescent chelate compounds� Journal of the American Chemical Society� 122, 3671 (2000).

� Z. D. Popovic, H. Aziz, N. Hu, P. N. M. dos Anjos, A. Ioannidis, �Degradation Mechanism of OLEDs based on AlQ3�, Conference Record of the 20th International Display Research Conference, pp. 333-336, Society for Information Display 2000.

� Z. D. Popovic, H. Aziz, N. Hu, P. N. M. dos Anjos, A. Ioannidis, �Long-term Degradation Mechanism in Small Molecule Based OLEDs�, Proceedings of IS&T�s NIP-16: International Conference on Digital Printing Technologies, pp. 350-353, The Society for Imaging Science and Technology 2000.

� H. Aziz, Z. Popovic, H. Hu, A. Hor, G. Xu �Long-term degradation mechanism of organic light emitting devices based on small molecules�, Mater. Res. Soc. Symp. Proc.� (2000),� 558(Flat-Panel Displays and Sensors--Principles, Materials and Processes),� 507-512

1999

� H. Aziz, Z.D. Popovic, N. Hu, A. Hor, and G. Xu, �Degradation mechanism of small molecule-based organic light-emitting devices� Science 283, 1900 (1999).

� Z. Popovic,� H. Aziz, N. Hu, A. Hor, and G. Xu,� �Mechanism of the intrinsic (long-term) degradation in AlQ3-based organic light emitting devices�, Proceedings of SPIE, Conference on Organic Light-Emitting Materials and Devices III, Denver, CO, July 1999, Vol. 3797, Pp 310-315.

1998

� H. Aziz, Z. Popovic, C.P. Tripp, N. Hu, A. Hor, and G. Xu, �Degradation processes at the cathode/organic interface in organic light emitting devices with Mg:Ag cathodes� Applied Physics Letters 72,� 2642 (1998).

� H. Aziz, Z. Popovic, S. Xie, C.P. Tripp, N. Hu, A. Hor, and G. Xu, �Humidity-induced Crystallization of tris(8-hydroxyquinoline) aluminum layers in organic light emitting devices� Applied Physics Letters 72, 756-758 (1998).

� Z. Popovic,� H.� Aziz, C.P.Tripp, N. Hu, A. Hor, and G. Xu, �Improving the efficiency and stability of organic light-emitting devices using mixed emitting layers� Proceedings of SPIE, Conference on Organic Light-Emitting Materials and Devices II, San Diego, CA, July 1998, Vol. 3476, Pp 68-73.

1997

� H. Aziz, and G. Xu, �Electric-field-induced degradation of poly(p-phenylenevinylene) electroluminescent devices� Journal of Physical Chemistry B� 101, 4009 (1997).

1996

� H. Aziz, and G. Xu, �A degradation mechanism of organic light-emitting devices� Synthetic Metals� 80, 7 (1996).