Flexible, Wearable Organic Light‐Emitting Fibers Based on PEDOT:PSS/Ag‐Fiber Embedded Hybrid Electrodes for Large‐Area Textile Lighting

Abstract

Organic light emitting diodes (OLEDs), which possess wonderful device performance and mechanical robustness have been extensively explored in textile lighting applications. In this work, an ITO‐free, PEDOT:PSS/Ag‐fiber hybrid transparent conducting electrode (TCE) embedded in polymeric substrate (denoted as hybrid‐fiber TCE henceforth) for the fabrication of large‐area OLEDs is designed. The optimum hybrid‐fiber TCE with a pitch of 150 µm shows extraordinarily low sheet resistance (Rsheet = 1.3 Ω ▫−1) and exceptional mechanical flexibility, exhibiting ≈100% Rsheet retention at a bending radius of up to ≈0.5 mm. The device performance of the resulting OLEDs based on hybrid‐fiber TCEs (fiber‐OLEDs) is on‐par with that of ITO‐based OLED analogues. More fascinatingly, organic light emitting fibers (OLEFs), obtained via slitting the fiber‐OLEDs, display a maximum luminance efficiency of ≈38.2 cd A−1 and a maximum external quantum efficiency of ≈10.9%, which surpasses all previously reported results. In addition, the OLEFs are mechanically robust and able to withstand a high degree of deformation, thus can be woven into fabric matrix for smart textile application. The vacuum‐free, scalable fabrication of the high performance OLEFs demonstrated herein is significant for the development of extremely large‐area smart textile applications.

En Route to Wide Area Emitting Organic Light‐Emitting Transistors for Intrinsic Drive‐Integrated Display Applications: A Comprehensive Review

“…[166] OLEF, in another context, is constructed by the mechanically robust and flexible hybrid-fiber as a transparent conducting electrode such as PEDOT: PSS/Ag-fiber embedded in a polymeric substrate, instead of commonly employed ITO conducting electrodes. [170] Upon woven these OLEF into the fabric cloth, a maximum luminance efficiency of ≈38.2 cd A −1 and a maximum EQE of ≈10.9% was observed, validating the significance of fiberbased substrates/conductive electrodes for the development of flexible and wearable optoelectronic devices. Earlier, Jensen et al, constructed multi-colored nanofiber OLET by combining para-hexaphenylene and 5,5′-di-4-biphenyl-2,2′-bithiophene as emitting nano fiber materials, which upon fabrication on to a silicon-based FET delivered both blue and green light operated via alternating current (AC)-gate voltage.…”

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

“…An important improvement in fiber OLED efficiencies was achieved by Ko et al in 2020 [72]. In particular, using a hybrid PEDOT:PSS/Ag fiber as a transparent conducting electrode (TCE) embedded in the polymeric substrate, it was possible to fabricate a fiber OLED characterized by a luminance of 4200 cd/m 2 , a CE of 39.6 cd/A, and an EQE of 11.3%, performances comparable to that of the corresponding planar ITO-OLED.…”

Highly flexible Ag nanowire network covered by a graphene oxide nanosheet for high-performance flexible electronics and anti-bacterial applications

“…A flexible and transparent conductive electrode (FTCE) is a thin film with high transparency, high conductivity, and outstanding flexibility [1][2][3]. Due to the rapid advancements in flexible electronics and wearable devices, FTCEs have gained a great deal of attention as a key component of flexible displays [4][5][6], flexible touch panels [7][8][9], flexible thin film heaters (TFHs) [10][11][12][13][14][15][16], photoelectric devices [17][18][19][20], and wearable electronics [21][22][23].…”

“…A flexible and transparent conductive electrode (FTCE) is a thin film with high transparency, high conductivity, and outstanding flexibility [ 1–3 ]. Due to the rapid advancements in flexible electronics and wearable devices, FTCEs have gained a great deal of attention as a key component of flexible displays [ 4–6 ], flexible touch panels [ 7–9 ], flexible thin film heaters (TFHs) [ 10–16 ], photoelectric devices [ 17–20 ], and wearable electronics [ 21–23 ]. Currently, most flexible electronics and wearable devices use Sn-doped In 2 O 3 (ITO) film coated on a flexible substrate through a typical magnetron sputtering process [ 24–26 ] owing to the high conductivity and transparency of commercially available ITO films.…”