Incorporating High‐Dielectric‐Constant Modified PVDF Into Alternating Current Electroluminescent Fibers to Boost Brightness

Alternating current electroluminescent (ACEL) fibers are regarded as a fundamental component essential for enabling display and interaction functionalities in next-generation wearable technologies like electronic textiles. However, the practical applications of current ACEL fibers have long been limited by their relatively low luminous brightness, which typically remains below 200 cd/m². Recognizing that the low dielectric constant of the commonly used polymer matrix in luminescent fibers largely limits their brightness, we developed a modified poly (vinylidene fluoride-co-chlorotrifluoroethylene) (M-PVDF) with a high dielectric constant, which is fully compatible with the solution-processing procedures and multilayer coaxial structure of ACEL fibers. It is not only easy to synthesize at a large scale but also exhibits excellent solution processability, high transparency (>90%), and good compatibility with ZnS particles, making it highly suitable for high-performance ACEL fibers. The ACEL fiber based on M-PVDF matrix achieves a remarkable brightness of 717 cd/m² at 110 V and 2 kHz, far surpassing that of conventional ACEL fibers. It also demonstrates outstanding stability and flexibility under harsh conditions, such as 80°C and -20°C for 7 days, 1 00 000 cycles of repeated friction, and a prolonged 80 h washing test. Furthermore, the 200-meter-long ACEL fibers produced at a large scale demonstrate high uniformity and stable luminance. These fibers could be woven into textiles for pattern display, showcasing their practical applicability across a wider range of illuminated environments.