Stretchable electronics, which contain a discrete LED chip interconnected with stretchable electrodes, show promise for use in a wide range of applications, including minimally invasive biomedical devices that can move with the body.
Researchers at the UCLA Henry Samueli School of Engineering and Applied Science (Los Angeles, CA) have demonstrated for the first time an intrinsically stretchable polymer light-emitting device by developing a simple process to fabricate the transparent devices using single-walled carbon nanotube polymer composite electrodes. The interpenetrating networks of nanotubes and the polymer matrix in the surface layer of the composites lead to low sheet resistance, high transparency, high compliance and low surface roughness.
|Polymer LED before stretching, stretched to 20% and 45% uniaxial strain. (Image courtesy of UCLA Henry Samueli School of Engineering and Applied Science)|
Recently published in the journal Advanced Materials, the metal-free devices can be linearly stretched up to 45% and the composite electrodes can be reversibly stretched by up to 50% with little change in sheet resistance.
Because the devices are fabricated by roll lamination of two composite electrodes that sandwich an emissive polymer layer, they uniquely combine mechanical robustness and the ability for large-strain deformation, due to the shape-memory property of the composite electrodes. This development will provide a new direction for the field of stretchable electronics.
The research was supported by the National Science Foundation.
Posted by Lee Mather
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