Autors: Aleksandrova, M. P., Andreev, S. K., Ruskova, I. N., Dobrikov, G. H.
Title: Flexible Thick Film Electroluminescent Devices: Influence of the Mechanical Stress on Layers Behavior
Keywords: Flexible OLED, Thick Films, Electroluminescent Coatings, Mechanical Stress

Abstract: The influence of the mechanical bending on flexible screen-printed organic light emitting devices upon their electrical properties has been examined. Our measurements showed that flexible printed coatings can be bent to small radii (5 mm and 2.5 mm) of curvature and still function, despite the increase of the electrical resistance of the electrodes from 45 to 62.1 Ohms/sq. This is ascribed to the mixture of two classes organic compounds (low molecular weight and polymeric) in suitable ratio, which guarantee high adhesion and stability against strain. Device failure is caused mainly by the transparent indium tin oxide (ITO) electrode that is not resistant to continuous bending at radius 5 mm, as well as to repeated bending over 2 000 that lead to cracks occurring. Internal stress induced in organic electroluminescent layers with different thickness was determined to be in the range |1|-|7| MPa, based on the radius of curvature. Current-voltage characteristics clearly show the limit of



    Annual Journal of Electronics, vol. 8, pp. 43-46, 2014, Bulgaria,

    Вид: публикация в международен форум, публикация в реферирано издание