Gradient‐Structured Polymer Fiber Mats for Broadly Tunable Multicolor and White Lasing

ABSTRACT

Random lasing has become highly advantageous for achieving colorful and white laser emission. Utilizing multiple light scattering in disordered media allows cost‐effective, flexible designs and seamless integration of multicolor gain dyes. Narrowband lasing from each dye further expands the accessible color range beyond standard photoluminescence. However, generating colorful and white light closely matching D65 and other standards remains challenging due to energy transfer between chromophores. Here, we present hierarchically designed electrospun polymer fiber mats with a gradient distribution of red, green, and blue (RGB) dyes, enabling wide‐range, gradually tunable multicolor and white lasing. While electrospun fibers are well‐studied, their use for adjustable, multicolor random lasing in a gradient hierarchical architecture is shown here for the first time. Spatial separation of the gain media limits energy transfer, allowing precise control of individual lasing bands. The resulting emission shows exceptional spectral tunability, aligning with sRGB, Adobe RGB, and DCI‐P3 standards. White lasing matches D‐series illuminants (D55, D65, D75) with deviations as low as 0.2% to 3%, representing a significant improvement over previously reported organic, hybrid, and inorganic systems. This approach establishes fiber mats as a versatile platform for wide‐gamut tunable random lasers with applications in Li‐Fi, sensors, and speckle‐free imaging.