Influence of conductivity and work function of polyaniline-based HIL on PLED device performance

Joerg R. Posdorfer; Bettina Werner; Bernhard Wessling; Susanne Heun; Heinrich Becker

doi:10.1117/12.510006

16 February 2004 Influence of conductivity and work function of polyaniline-based HIL on PLED device performance

Joerg R. Posdorfer, Bettina Werner, Bernhard Wessling, Susanne Heun, Heinrich Becker

Proceedings Volume 5214, Organic Light-Emitting Materials and Devices VII; (2004) https://doi.org/10.1117/12.510006
Event: Optical Science and Technology, SPIE's 48th Annual Meeting, 2003, San Diego, California, United States

Abstract

Polyaniline (PAni) dispersions can be efficiently used as hole injection layers (HIL) for passive and active matrix display applications. In earlier work the influence of conductivity and work function of HILs spin coated from water based PAni/PSS dispersions on device performance had already been presented. Recent investigations on hole transport mechanism in polyaniline systems now show the necessity of a minimum conductivity and an optimum work function for hole injection. Electrochemical Impedance Spectroscopy measurements combined with luminescence investigations showed that the lateral conductivity in the PAni films must be >10^-6 S/cm. Otherwise, a decrease in maximum efficiency and an increase in driving voltage in dependence on coating thickness occurs. Work function investigations on water-free, highly conductive polyaniline dispersions emphasize the theory of an optimum range for hole injection from the anode into the light emitting polymer. The work function of highly conductive, non-aqueous PAni dispersion (0.1-5 S/cm) was determined by Scanning Kelvin Probe method to be 4.5 - 4.7 eV, which is outside of the optimum range at about 4.95 - 5.05 eV for polymeric light emitting diodes, resulting in poor efficiency values (max. 30 - 50% compared to PAni/PSS standard).

Citation Download Citation

Joerg R. Posdorfer, Bettina Werner, Bernhard Wessling, Susanne Heun, and Heinrich Becker "Influence of conductivity and work function of polyaniline-based HIL on PLED device performance", Proc. SPIE 5214, Organic Light-Emitting Materials and Devices VII, (16 February 2004); https://doi.org/10.1117/12.510006

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available