Improving the lifetime of a polymer light-emitting diode by introducing solution processed tungsten-oxide

We report a polymer light-emitting diode (PLED) using solution processed tungsten-oxides (WOx). Coating of a thin WOx layer on PEDOT:PSS increases the current efficiency of PLED from 9.11 to 9.90 cd A−1 because of the improved conductivity of the PEDOT:PSS due to the incorporation of WOx. Improvement of the conductivity of PEDOT:PSS promotes hole injection into the emission layer. The lifetime of a PLED with WOx layers on both sides of PEDOT:PSS is 1.8 × 106 h which is around 20 times longer than that of the control device at 1000 cd m−2. The enhanced lifetime is due to the suppression of the indium diffusion from ITO to PEDOT:PSS by WOx and also due to the prevention of acidic damage that can occur to ITO and the organic emission layer by sulfate ions in PEDOT:PSS.

[1]  Wolfgang Kowalsky,et al.  Role of the deep-lying electronic states of MoO3 in the enhancement of hole-injection in organic thin films , 2009 .

[2]  Sunghan Kim,et al.  Degradation of PLEDs and a way to improve device performances , 2004 .

[3]  S. Chua,et al.  Stabilization of electrode migration in polymer electroluminescent devices , 2002 .

[4]  T. Riedl,et al.  Highly efficient simplified organic light emitting diodes , 2007 .

[5]  M.J.A. de Voigt,et al.  Stability of the interface between indium-tin-oxide and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) in polymer light-emitting diodes , 2000 .

[6]  Yongfang Li,et al.  Solution-Processed Tungsten Oxide as an Effective Anode Buffer Layer for High-Performance Polymer Solar Cells , 2012 .

[7]  Xuezhong Jiang,et al.  Highly Efficient Hole Injection Using Polymeric Anode Materials for Small-Molecule Organic Light-Emitting Diodes , 2009 .

[8]  Shuti Li,et al.  Ultrathin nickel oxide film as a hole buffer layer to enhance the optoelectronic performance of a polymer light-emitting diode. , 2011, Optics letters.

[9]  Ki-Beom Kim,et al.  Effect of ultraviolet-ozone treatment of indium-tin-oxide on electrical properties of organic light emitting diodes , 2004 .

[10]  Jin Jang,et al.  Enhanced efficiency of organic photovoltaic cells using solution-processed metal oxide as an anode buffer layer , 2011 .

[11]  Karsten Walzer,et al.  Ultrastable and efficient red organic light emitting diodes with doped transport layers , 2006 .

[12]  Shui-Tong Lee,et al.  Metal diffusion from electrodes in organic light-emitting diodes , 1999 .

[13]  Q. Gong,et al.  Study on scalable Coulombic degradation for estimating the lifetime of organic light-emitting devices , 2011 .

[14]  M. Rusu,et al.  Role of ITO and PEDOT:PSS in stability/degradation of polymer:fullerene bulk heterojunctions solar cells , 2010 .

[15]  Nikos Konofaos,et al.  Tungsten oxides as interfacial layers for improved performance in hybrid optoelectronic devices , 2011 .

[16]  B. Cumpston,et al.  Electromigration of aluminum cathodes in polymer‐based electroluminescent devices , 1996 .

[17]  R. Hatton,et al.  The effect of a MoOx hole-extracting layer on the performance of organic photovoltaic cells based on small molecule planar heterojunctions , 2010 .

[18]  Jin Cao,et al.  High stability and low driving voltage green organic light emitting diode with molybdenum oxide as buffer layer , 2008 .

[19]  N. Huby,et al.  Correlation between the Indium Tin Oxide morphology and the performances of polymer light-emitting diodes , 2005 .

[20]  A. Kahn,et al.  Charge generation layers comprising transition metal-oxide/organic interfaces: Electronic structure and charge generation mechanism , 2010 .

[21]  Friedrich-Karl Bruder,et al.  PEDT/PSS for efficient hole-injection in hybrid organic light-emitting diodes , 2000 .

[22]  S. Dunn,et al.  Cathodic and Anodic Material Diffusion in Polymer/Semiconductor‐Nanocrystal Composite Devices , 2007 .

[23]  K. Lim,et al.  Tunable work function of a WOx buffer layer for enhanced photocarrier collection of pin-type amorphous silicon solar cells , 2011 .