Bright‐Multicolor, Highly Efficient, and Addressable Phosphorescent Organic Light‐Emitting Fibers: Toward Wearable Textile Information Displays

Abstract

Fiber-based light-emitting devices, which can be directly integrated into daily clothes, have emerged as a next-generation display form factor that can provide informational hyper-connections between humans and devices. However, although various approaches have provided advanced wearability, challenges remain for visualizing information, such as high power consumption resulting from high driving voltage and low current efficiency (CE), limited brightness making information difficult to recognize, and lack of addressability for displaying information. Here, a novel fiber-based textile display that can surmount those challenges by successfully introducing phosphorescent organic light-emitting diodes (phOLEDs) based on a dip-coating method and an addressable structure on cylinder-shaped fiber is reported. The fiber phOLEDs exhibit unprecedented optoelectronic performance, including brightness, CE, and driving voltages comparable to those of conventional glass-based OLEDs. Particularly, they show the highest CE values of 16.3, 60.7, and 16.9 cd A -1 for red, green, and blue, respectively, among results reported thus far. Also, the fiber phOLEDs with an addressable structure implementing independent pixels can be operated by the matrix-addressable scheme. Based on unique deformability which is confirmed by flexibility tests, the performance capabilities, and addressability, letter information can be successfully visualized on daily clothes, demonstrating the potential for realizing truly wearable textile displays.

Perovskite fiber-shaped optoelectronic devices for wearable applications

“…Realizing a wearable light fidelity (LIFI) system with the merits of portability, conformability, and safe and high-speed wireless communication will have boundless prospects in the Internet of Things terminals. 138,139 In terms of the data transmission part in wearable LiFi, electroluminescent (EL) fibers based on materials such as organics, 140 inorganic phosphors, 141 and polymer materials 142 have been reported for the construction of LiFi systems. However, all these materials show numerous shortcomings, making them less suitable for LIFI systems.…”

Organic light‐emitting fibers and fabrics for truly wearable smart displays: Recent progress and future opportunities

“…Since the leading technology used to fabricate commercial products is phosphorescent materials, which can theoretically utilize 100% excitons, it was natural to verify whether phosphorescent OLEDs (phOLEDs) could be successfully implemented on fiber. In 2021, Hwang et al reported red, green, and blue fiber phOLEDs (RGB fiber phOLEDs), simultaneously demonstrating the successful implementation of phosphorescence and a passive matrix‐based addressable scheme that could visualize letter information beyond the level of a single pixel 41 . In their work, the fiber phOLED was also fabricated in an inverted structure via the dip‐coating method (Figure 3A).…”

“…Copyright 2021, The Authors, Wiley-VCH. 41 Reproduced with permission. Copyright 2016, The Authors, Wiley-VCH.…”

“…Various light sources have been used for each approach, including electrochemical cells (LECs), [19][20][21] alternating-current electroluminescence (ACEL) devices, [22][23][24][25][26][27][28][29][30] inorganic light-emitting diodes (LEDs), [31][32][33] quantum dots (QDs), 34,35 organic light-emitting diodes (OLEDs), [36][37][38][39][40][41][42][43][44][45][46] and others. [47][48][49][50] In terms of wearability and display technologies, textile displays should not only provide flexibility comparable to a natural textile but also avoid the risk of electric shock from the high operating voltages of textile displays.…”

Light-Emitting Textiles: Device Architectures, Working Principles, and Applications

“…Moreover, the woven OLED textile was stable in water and under applied tensile force. The most recent work on fiber OLEDs reports about the deposition of a phosphorescent active layer via dip-coating technique [75]. In particular, three different phosphorescent materials were tested as active layers to prepare phosporescent OLEDs (phOLEDs) with three different emitting colors (red, green, and blue).…”