Distortion‐Free Stretchable Light‐Emitting Diodes via Imperceptible Microwrinkles. Issue 9 (19th May 2020)

• Record Type: Journal Article
• Authors: Jeong, Sujin; Yoon, Hyungsoo; Lee, Byeongmoon; Lee, Seunghwan; Hong, Yongtaek
• Is Part Of: Advanced materials technologies. Volume 5:Issue 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-19
• Subjects: distortion‐free pixels -- light‐emitting diodes -- solution process -- stretchable electronics -- wrinkle structures; Materials science -- Periodicals; Technological innovations -- Periodicals; Materials science; Technological innovations; Periodicals; 620.1105
• DOI: 10.1002/admt.202000231
• Languages: English
• ISSNs: 2365-709X

Abstract

Abstract: Stretchable organic light‐emitting diodes (OLEDs) have been considered as a promising technology for next‐generation free‐form and wearable displays. However, an approach to ensure both high device performance and high resolution has not yet been suggested. While introducing a wrinkled structure in the active pixel areas is a decent method, the formation of out‐of‐plane macroscopic wrinkles having a wavelength of a few hundred µm has caused distortion in the shape of the pixel, which is a critical drawback for a matrix‐configured display demanding a sharp pixel definition. Herein, microwrinkled OLEDs are fabricated to define a distortion‐free pixel by direct deposition of OLEDs on biaxially prestretched elastomeric substrate, being feasible by a low‐temperature‐based solution process. The total thickness of the device can be significantly reduced up to 350 nm, producing the imperceptible microwrinkles having a wavelength under 20 µm. The microwrinkled OLEDs show a luminance over 8000 cd m −2 and maximum current efficiency of 7.76 cd A −1, which is comparable to the device without wrinkled structure. Finally, a stretchable 4 × 4 OLED pixel array with a microwrinkled structure is demonstrated showing sharply defined square‐patterned emission, proving the potential in the future high‐resolution stretchable display. Abstract : Stretchable wrinkled polymer light‐emitting diodes without pixel distortion are reported by direct deposition on a prestretched elastomeric substrate. A low‐temperature‐based solution process facilitates the processability and enables the scale of a wrinkle structure to be engineered to the imperceptibly microscopic level. The microwrinkled structure suppresses the distortion caused by out‐of‐plane wavy structure by large‐scale wrinkles, advancing the feasibility of stretchable display with high resolution.