Highly Flexible Fabric‐Based Organic Light‐Emitting Devices for Conformal Wearable Displays

Abstract Organic light‐emitting devices on fabrics (Fa‐OLEDs) are outstanding candidates for high‐quality wearable displays. High flexibility and conformality to clothes deformations are required for Fa‐OLEDs to keep wearing comfort during body movement. However, it is a great challenge to realize an ultrathin planarization layer with ultrasmooth surface simultaneously on the rough surface of fabrics for Fa‐OLEDs fabrication. Here, a template‐stripping process is employed to fabricate both ultrathin and ultrasmooth planarization layers for highly flexible and efficient Fa‐OLEDs. The thickness of the planarization layer is as small as 3 µm while its surface roughness is only 0.6 nm. The planarization process is insensitive to the textures and morphology of fabrics. As a result, the Fa‐OLEDs show excellent electroluminescent performance and flexibility. The maximum current efficiency of 78 cd A⁻¹ is comparable with that of the conventional planar devices. The variation of current efficiency is as small as 8% after 1000 times of bending with 1 mm bending radius, which is the best bending stability of the flexible Fa‐OLEDs reported to date. The Fa‐OLEDs are successfully used as conformal wearable displays by sewing on clothes and keep working well with a series of arm movements.