Weavable and Highly Efficient Organic Light-Emitting Fibers for Wearable Electronics: A Scalable, Low-Temperature Process

Abstract

Fiber-based wearable displays, one of the most desirable requisites of electronic textiles (e-textiles), have emerged as a technology for their capability to revolutionize textile and fashion industries in collaboration with the state-of-the-art electronics. Nonetheless, challenges remain for the fibertronic approaches, because fiber-based light-emitting devices suffer from much lower performance than those fabricated on planar substrates. Here, we report weavable and highly efficient fiber-based organic light-emitting diodes (fiber OLEDs) based on a simple, cost-effective and low-temperature solution process. The values obtained for the fiber OLEDs, including efficiency and lifetime, are similar to that of conventional glass-based counterparts, which means that these state-of-the-art, highly efficient solution processed planar OLEDs can be applied to cylindrical shaped fibers without a reduction in performance. The fiber OLEDs withstand tensile strain up to 4.3% at a radius of 3.5 mm and are verified to be weavable into textiles and knitted clothes by hand-weaving demonstrations. Furthermore, to ensure the scalability of the proposed scheme fiber OLEDs with several diameters of 300, 220, 120, and 90 μm, thinner than a human hair, are demonstrated successfully. We believe that this approach, suitable for cost-effective reel-to-reel production, can realize low-cost commercially feasible fiber-based wearable displays in the future.

Materials and Structures toward Soft Electronics

“…e) A functional fiber with light‐emitting characteristics. Reproduced with permission . Copyright 2018, American Chemical Society.…”

Recent Progress of Fiber Shaped Lighting Devices for Smart Display Applications—A Fibertronic Perspective

“…Copyright 2007, Wiley‐VCH. b–e) Reproduced with permission . Copyright 2018, American Chemical Society.…”

“…More recently, Kwon et al also reported fiber‐based OLEDs based on a combination of a solution process (e.g., dip coating method) and a thermal evaporation process . Solution processing offers cost‐effective and large‐area mass production of OLED devices but thus far almost all solution‐processed OLEDs reported in the literature have still exploited the combination of a solution process and subsequent vacuum deposition of top electrodes.…”

The Rise of Fiber Electronics

“…[40,41] Thea ctive layer typically needs to be very thin for effective charge separation and transport, and the outer electrode layer should be transparent to guarantee sufficient light absorption or high light emission. Forp hotovoltaic or lighting devices,t he key is to produce continuous active and transparent electrode layers on the curved fiber surface.…”