Functional Groups‐Driven Molecular Design for Broad‐Spectrum Clusteroluminescence in Scalable Monodisperse Polymer Microspheres

ABSTRACT Achieving multicolor, precisely tunable cluster‐induced emission in nonconjugated polymers remains a considerable challenge. Herein, we present a generalizable and scalable methodology for fabricating monodisperse, color‐tunable clusteroluminescence (CL) microspheres, enabling multimodal color tuning across the spectrum from blue to orange‐red through precise control of monomer type and ratio, sulfonation time, and pH conditions. Density functional theory (DFT) simulations demonstrate that conformational rigidity, resulting from the synergistic combination of prevalent hydrogen‐bonding interactions, short interatomic contacts, and oxygen cluster formation, significantly enhances emission efficiency, leading to dual broadband visible emissions across the 400–700 nm wavelength range. The optimized sulfonated poly(divinylbenzene‐styrene‐methyl methacrylate) microspheres with 30% methyl methacrylate (MMA) content (SPSMMAs‐30) exhibit excellent monodispersity and strong fluorescence across 13 standard channels of flow cytometry, with fluorescence coefficient of variation (CV) values consistently below 3%, fulfilling requirements for routine flow cytometer calibration. Compared with commercial calibration microspheres, SPSMMAs‐30 show significantly higher photobleaching resistance and long‐term environmental stability. Significantly, this protocol enables the first kilogram‐scale synthesis of CL microspheres with highly reproducible optical properties. Furthermore, SPSMMAs‐30 demonstrate sensitive tetracycline detection and promising performance in multicolor anticounterfeiting applications, substantially broadening the scope of nonconjugated CL materials for biomedicine, diagnostics, and materials science.