Stretchable Organic Light‐Emitting Devices with Invisible Orderly Wrinkles by using a Transfer‐Free Technique

Stretchable organic light-emitting devices (SOLEDs) based on orderly wrinkles have become a promising candidate for the new-generation deformable displays because of their high-optoelectronic performance and stretching stability. However, the complex thin film transfer process to form the wrinkles and the decreased display quality caused by the large-period wrinkles with a few hundreds of microns are obstacles to their practical applications. Herein, a simple transfer-free technique is designed to introduce the orderly wrinkles with a much smaller period of 70 mu m into the SOLEDs, which is the smallest value reported to date for the orderly wrinkles integrated in the SOLEDs. The small-period wrinkles are invisible by naked eyes and beneficial to the applications of the SOLEDs in high-quality stretchable displays. The electroluminescence performance of the SOLED with 20% stretchability are comparable to those of the rigid OLEDs on glass substrates. After 2000 cycles of stretching, the luminance of the device remained at 90% of its initial value. Meantime, the transfer-free technique is compatible with the flexible encapsulation process. The luminance of the encapsulated SOLEDs exhibit negligible decline after 600-min continuous operation under ambient condition. This work provides an effective solution for achieving high-performance SOLEDs by a simple process.