Cracking of Aluminum and Silver Alloy Thin Films on Polymer Thin Films

抄録

Critical cracking strain of transparent conductive polymer thin films, aluminum and silver alloy thin films on polymer thin films prepared on a flexible polyethylene naphthalate (PEN) substrate was investigated by applying tensile strain to the specimens with monitoring the electric resistance of the thin films. The final target of the present research is the improvement of flexibility of organic devices, flexible displays and flexible organic light emitting diodes (OLEDs). As a result, it was found that transparent conductive polymer PEDOT: PSS films do not cause cracking and the electric resistance increased theoretically by around 10% of strain. Regarding the two layer thin films, cracking initiated at a strain of around 4% then the electric resistance started increasing. The reason has suggested that cracking was caused by the strain resulting in cracking with forming network shape. Furthermore it was found that the aspect of the cracking depends on the under-layers suggesting the effect of ductility and adhesion of the films.