Spatiotemporal engineering of dynamic color in alternating‐current‐driven light‐emitting devices

Electrically driven light‐emitting devices underpin modern lighting, displays, and intelligent interfaces. While conventional systems rely on direct current, AC‐driven devices employ periodically varying electrical excitation, offering potential opportunities for simplified power interfacing in appropriately matched systems and providing additional temporal degrees of freedom for dynamic color modulation. However, precise spectral control remains challenging because emission arises from the coupled spatiotemporal evolution of alternating electric fields and heterogeneous emissive centers rather than static material properties. Here, we present a mechanism‐driven framework that interprets color tuning in AC‐driven light‐emitting devices as a spatiotemporal process of electric‐field‐charge interactions. Within this framework, existing strategies are systematically organized along three cooperative dimensions: emissive center engineering, device architecture design, and driving signal modulation. By explicitly linking microscopic carrier dynamics including excitation pathways, recombination zones, and energy‐transfer processes with macroscopic spectral evolution, this review provides a coherent picture that bridges materials design, device physics, and electrical operation. We further highlight emerging applications in intelligent lighting, flexible and stretchable displays, interactive sensing, and optical anti‐counterfeiting, demonstrating how dynamic spectral tunability enables functionalities beyond conventional DC‐driven systems. Finally, key challenges and future opportunities are discussed, encompassing efficiency enhancement, spectral stability, chromaticity‐luminance decoupling, and sustainable emissive materials, offering a roadmap for the design of next‐generation dynamically tunable optoelectronic systems.