Back to articles
Articles
Volume: 17 | Article ID: art00019_2
Image
ITO Modification for More Efficient Hole Injection in Organic Light Emitting Diodes
  DOI :  10.2352/ISSN.2169-4451.2001.17.1.art00019_2  Published OnlineJanuary 2001
Abstract

Indium Tin Oxide is the most commonly used anode electrode in organic light emitting diodes (OLEDs). A critical parameter for charge injection is its workfunction, varies between 4.5 and 5.1 eV, depending on the sample preparation and cleaning procedure. These large variations in the workfunction translate to even larger variations in the injected current, which is a major issue for the fabrication of efficient OLEDs. We demonstrate a way to treat ITO and get a contact with good injection characteristics, regardless of the ITO preparation procedure. We have carried out direct measurements of the injection efficiency at the ITO/TPD contact (TPD is N-N'-diphenyl-N-N'-bis(3-methylphenyl)-1-1-biphenyl-4,4'-diamine, a commonly used hole transport layer). The contact is found to be current-limiting, supplying TPD only with 1% of the space charge limited current. By introducing a thin layer of polyaniline, or a thin film of a high work function metal, the injection efficiency approaches 100%, i.e. the contact becomes Ohmic. The performance of the contact shows little sensitivity to the details of the ITO preparation. A mechanism for this improvement is proposed. The change in the characteristics of TDP-based OLEDs are discussed.

Subject Areas :
Views 1
Downloads 0
 articleview.views 1
 articleview.downloads 0
  Cite this article 

Yulong Shen, Ken Diest, George Malliaras, "ITO Modification for More Efficient Hole Injection in Organic Light Emitting Diodesin Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP17),  2001,  pp 531 - 531,  https://doi.org/10.2352/ISSN.2169-4451.2001.17.1.art00019_2

 Copy citation
  Copyright statement 
Copyright © Society for Imaging Science and Technology 2001
72010410
NIP & Digital Fabrication Conference
nip digi fabric conf
2169-4451
Society of Imaging Science and Technology
7003 Kilworth Lane, Springfield, VA 22151, USA