Highly Stretchable Carbon Nanotube Fibers with Tunable and Stable Light Emission

Carbon nanotubes (CNTs) possess intriguing photoluminescence properties, and CNT fibers emit strong incandescent light thus act as macroscopic light sources. So far, straight‐shaped CNT fibers are a focus of study and their emission properties are elucidated. Here, the authors show that helical‐shaped single‐walled carbon nanotube (SWNT) fibers produce uniform and stable incandescent light along the entire fiber under moderate voltages, and the emission intensity is tailored over a wide range by the applied voltage and the elongation of the fiber (up to ≈70% strain), and in a reversible way during mechanical deformation. Their highly stretchable SWNT fibers with tunable light emission have promising applications in emerging research areas such as wearable electronics and high‐performance optoelectronic fiber systems.