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

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 (R_sheet = 1.3 Ω ▫⁻¹) and exceptional mechanical flexibility, exhibiting ≈100% R_sheet 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.