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Imperceptibly micro-wrinkled organic light-emitting diodes for distortion-free stretchable display applications

We report imperceptibly micro-wrinkled organic light-emitting diodes (OLEDs) to define distortion-free pixel by in-situ deposition on two-dimensionally pre-stretched polydimethylsiloxane (PDMS) substrate. The developed fabrication process includes surface engineering for a low-temperature solution process. After releasing the pre-strain, a micro-wrinkled structure facilitates to maintain the clear shape of the pixel with the wrinkle period under 20 µm that is unrecognizable to the human eyes, whereas wrinkles of hundreds of µm are formed when using plastic films. The micro-wrinkled OLEDs show a luminance over 8,000 cd/m2, a maximum current efficiency of 7 cd/A and can endure two-dimensional 20% strain. Our in-situ fabrication method can become a new framework for stretchable OLEDs with simple and low-cost fabrication with improved visibility.