An Ultrastretchable Reflective Electrode Based on a Liquid Metal Film for Deformable Optoelectronics

Stretchable optoelectronics represent an emerging technology featuring soft mechanical properties. The advancements in this active area rely on the development of compliant electronic materials. Currently, the deformable forms of light-emitting devices often exhibit double-side emissions due to the lack of stretchable reflective electrodes. This study reports a facile procedure to deposit smooth and uniform liquid metal films over large-area elastomeric substrates as stretchable reflective electrodes. The as-prepared electrodes exhibit low sheet resistance (0.15 Ω sq–1), high optical reflectance (95% at 550 nm), and ultrahigh deformability (500% strain). The electrode shows sufficient durability to survive repetitive tensile deformations. Successful implementation of a liquid metal electrode in a stretchable light-emitting device achieves single-side emission with enhanced light extraction. The stretchable reflective electrode reported here represents a key building component to enable a broad range of applications such as deformable lighting, wearable displays, and soft robotics.