Rough Surface Enhanced Interfacial Synthesis of Core‐Shell Magnetic Fluorescent Microspheres for Enhanced Latent Fingerprint Visualization

Abstract Developing latent fingerprints is extremely significant for personal identification and criminal investigation. Sub‐micrometer core‐shell structured magnetic fluorescent composite which combines the merits of noncontact responsiveness strong fluorescence emission highly desired visualization fingerprint on various substrates with high resolutions. However, it remains a great challenge to synthesize uniform composites well‐defined structure functionalities due uncontrollable heterogeneous growth. Herein, urea‐assisted rough interface precipitation method proposed controllably microspheres (Fe 3 O 4 @mesoSiO 2 @Y :Eu 3+ ). The core mesoporous silica shell ) possess huge guest‐host interface, numerous nucleation sites, surface morphology, facilitating efficient adsorption Y /Eu ions, further controllable deposition metal (Y, Eu) hydroxides induced by slow release OH − CO 2− anions via in‐solution decomposition urea. After subsequent thermal annealing, obtained Fe magnetization convenient manipulation, intensity negligible quenching effect, enabling superior performance in contrast resolution substrates.