Highly Efficient Organic Devices Based on Electrically Doped Transport Layers

Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany.
Chemical Reviews (Impact Factor: 45.66). 05/2007; 107(4):1233-71. DOI: 10.1021/cr050156n
Source: PubMed
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The technology of white organic light-emitting diodes (WOLEDs) is attracting growing interest due to their potential application in indoor lighting. Nevertheless the simultaneous achievement of high luminous efficacy (LE), high color rendering index (CRI), very low manufacturing costs and compatibility with flexible thin substrates is still a great challenge. Indeed, very high efficiency devices show usually low values of CRI, not suitable for lighting applications, and use expensive indium tin oxide (ITO) electrodes which are not compatible with low cost and/or flexible products. Here we show a novel low cost ITO-free WOLED structure based on a multi-cavity architecture with increased photonic mode density and still broad white emission spectrum, which allows for simultaneous optimization of all device characteristics. Without using out-coupling optics or high refractive index substrates, CRI of 85 and LE as high as 33 lm W−1 and 14 lm W−1 have been demonstrated on ITO-free glass and flexible substrates, respectively.
    Organic Electronics 11/2013; 14(11):2840-2846. DOI:10.1016/j.orgel.2013.07.034 · 3.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It is challenging to obtain broadband emission spectra in top-emitting white organic light-emitting diodes (WOLEDs) due to the well known microcavity effects. In this work, we demonstrate that the microcavity effects can be greatly alleviated by employing a low reflection tri-cathode-layer Yb (5nm)/Au (15nm)/MoO3 (35nm). Top-emitting WOLEDs with evenly separated red, green and blue emission peaks have been achieved. The white emission spectra show weak angle dependence as well. At a luminance of 1000cd/m2, the top-emitting WOLEDs show an efficiency of 23cd/A, 10.5lm/W, a 1931 Commission International de L’Eclairage coordinate of (0.36, 0.42) and a high color rendering index of 85. The top-emitting WOLEDs have been successfully applied in the Si based microdisplay.
    Organic Electronics 12/2011; 12(12):2065-2070. DOI:10.1016/j.orgel.2011.08.014 · 3.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bisazomethine dyes, which are synthesized using diaminomaleonitrile and aminobenzaldehydes, exhibit red fluorescence in solution and in the solid state. Several bisazomethine dyes are known to form J-aggregates in vapour-deposited films. In this work, novel bisazomethine dyes were synthesized and the effect of phenyl ring substitution on the J-aggregate formation in vapour-deposited films was examined. The optical properties of the dyes were examined in solution and in the solid state through molecular orbital calculations. Four derivatives were found to form J-aggregates in vapour-deposited films as determined from the shape of the spectrum and the absorption edge.
    Dyes and Pigments 07/2011; 90(1):56-64. DOI:10.1016/j.dyepig.2010.11.009 · 3.47 Impact Factor