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http://dx.doi.org/10.4313/JKEM.2006.19.6.563

Work Function Increase of ITO Modified by Self Assembled Monolayer for Organic Electrical Devices  

Jee Seung-Hyun (건국대학교 신기술융합학과)
Kim Soo-Ho (건국대학교 신기술융합학과)
Ko Jae-Hwan (건국대학교 신기술융합학과)
Yoon Young-Soo (건국대학교 신기술융합학과)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.19, no.6, 2006 , pp. 563-567 More about this Journal
Abstract
Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.
Keywords
Organic light emitting diode(OLED); Organic thin film transistor(OTFT); Indium tin oxide(ITO); Work function; Self assembled monolayer(SAM);
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1 H. Kobayashi, T. Ishida, K. Nakamura, Y. Nakato, and H. Tsubomura, 'Properties of indium tin oxide films prepared by the electron beam evaporation method in relation to characteristics of indium tin oxide/silicon oxide/silicon junction solar cells', J. Appl. Phys., Vol. 72, p. 5288, 1992
2 W. G. Haines and R. H. Bube, 'Effects of heat treatment on the optical and electrical properties of indium-tin oxide films', J. Appl. Phys., Vol. 49, p. 304, 1978   DOI   ScienceOn
3 X. Xu, G. Yu, Y. Liu, and D. Zhu, 'Electrode modification in organic light-emitting diodes', Displays, Vol. 27, p. 24, 2001   DOI   ScienceOn
4 F. Amy, C. Chan, and A. Kahn, 'Polarization at the gold/pentacene interface', Organic Electronics, Vol. 6, p. 85, 2005   DOI   ScienceOn
5 I. H. Kim, S. H. Park, J. J. Kim, and H. M. Kim, 'Effects of RF-plasma treatment in various oxygen atmospheres on the surfaces of ITO film', Sae Mulli(The Korean Physical Society), Vol. 48, No.4, p. 346, 2004
6 R. Maboudian and R. T. Howe, 'Critical review : Adhesion in surface micro mechanical structures', J. Vac. Sci. Technol., Vol. B15, p. 1, 1997
7 B. Kim, C. Oh, K. Chun, T. Chung, J. Byun, and Y. Lee, 'A new class of surface modifiers for stiction reduction', IEEE international workshop on MEMS, p. 189, 1999
8 S. F. J. Appleyard, S. R. Day, R. D. Pickford, and M. R. Willis, 'Organic electro-luminescent devices: enhanced carrier injection using SAM derivatized ITO electrodes', J. Mater. Chem., Vol. 10, p, 169, 2000   DOI   ScienceOn
9 Timothy J. Gardner, C. Daniel Frisbie, and Mark S. Wrighton, 'Systems for orthogonal self-assembly of electroactive monolayers on Au and ITO: An approach to molecular electronics', J. Am. Chem. Soc., Vol. 117, p. 6927, 1995   DOI   ScienceOn