Stretchable organic light emitting diodes: a novel architecture based on a low Young’s modulus stress-relief layer

Abstract

Electronics device that can be attached to the human body is attracting a great amount of attention as a building block for futuristic wearable IT systems. Due to the elastic or moving nature of the human skin and body parts, those body-attachable devices including information displays are preferred to exhibit a certain degree of stretchability [1-2]. However, due to the lack of stretchable semiconductors and transparent conductors, stretchable displays using organic light emitting diodes (OLEDs) are difficult to realize and, if any, less efficient than rigid or flexible OLEDs. Development of materials that are stretchable must be continued, but realizing a stretchable platform that meets the stretchability and performance requirements, at the same time. In this work, we propose stretchable OLEDs that are formed on a plurality of rigid isolation islands connected via serpentine interconnectors. Underneath the rigid platforms, a low Young’s modulus (Y) layer is introduced to relieve mechanical stress of devices grown on top of rigid isolation lands. [See Fig. 1(a) and 1(b)]. Upon use of very low-Y medium, applied strain on rigid islands and interconnectors are greatly reduced [3]. Electrodes fabricated on this stretchable platform show a high degree of stretchablility (interconnector is stretched 140 %, 5000 cycles) with very low resistance variation as shown in Fig.1 (c). Stretchable OLEDs based on this electrodes also can be stretched 140~150% without a significant drop in the electrical characteristic and brightness as shown in Fig.1 (d).