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Deep-Level Optical Spectroscopy Investigation of Trap Levels in Tris(8-Hydroxyquinoline) Aluminum

Published online by Cambridge University Press:  26 February 2011

Yoshitaka Nakano ,
Koji Noda ,
Hisayoshi Fujikawa ,
Takeshi Morikawa  and
Takeshi Ohwaki
Yoshitaka Nakano
Affiliation:
y-nakano@mosk.tytlabs.co.jp, TOYOTA Central Research and Development Laboratories, Inc., Inorganic Materials Laboratory, Nagakute, Aichi, 480-1192, Japan, +81-561-63-4302, +81-561-63-5328
Koji Noda
Affiliation:
e0657@mosk.tytlabs.co.jp, TOYOTA Central Research and Development Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
Hisayoshi Fujikawa
Affiliation:
e0888@mosk.tytlabs.co.jp, TOYOTA Central Research and Development Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
Takeshi Morikawa
Affiliation:
e0890@mosk.tytlabs.co.jp, TOYOTA Central Research and Development Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
Takeshi Ohwaki
Affiliation:
e0583@mosk.tytlabs.co.jp, TOYOTA Central Research and Development Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
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Abstract

We have investigated band gap states in tris(8-hydroxyquinoline) aluminum (Alq3) with and without quinacridone (Qd) doping on fabricated indium-tin-oxide (ITO)/Alq3(:Qd)/LiF/Al devices by using a deep-level optical spectroscopy (DLOS) technique. Non-doped Alq3 sample shows a discrete trap level located at ∼1.39 eV below the lowest unoccupied molecular orbital band in addition to near-band-edge transitions at 2.2 - 3.6 eV. The pronounced 1.39 eV level is attributable to an intrinsic nature of Alq3 and can be active as an efficient generation-recombination (GR) center that may impact the photophysical properties. On the other hand, Qd-doped Alq3 sample exhibits a new deep level at ∼2.40 eV with increasing the double carrier injection rate, corresponding to the highest occupied molecular orbital band of the Qd. Simultaneously, this GR center is subject to charge up positively due to the presence of holes injected into the Qd doping level for Qd-doped Alq3.

Keywords

organicelectrical propertieselectronic material
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 965: Symposium S – Organic Electronics – Materials, Devices and Applications , 2006 , 0965-S09-21
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1. Tang, C. W. and VanSlyke, S. A., Appl. Phys. Lett. 51, 913 (1987).Google Scholar
2. Chantre, A., Vincent, G., and Bois, D., Phys. Rev. B 23, 5335 (1981).Google Scholar
3. Nakano, Y., Morikawa, T., Ohwaki, T., and Taga, Y., Appl. Phys. Lett. 86, 132104 (2005).Google Scholar
4. Nakano, Y., Noda, K., Fujikawa, H., Morikawa, T., Ohwaki, T., and Taga, Y., Appl. Phys. Lett. 88, 252104 (2006).Google Scholar
5. Campbell, I. H., Smith, D. L., and Ferraris, J. P., Appl. Phys. Lett. 66, 3030 (1995).Google Scholar
6. Aziz, H., Popovic, Z. D., Hu, N., Hor, A., Xu, G., Science 283, 1900 (1999).Google Scholar