Engineering particles for sensing applications via in-situ synthesizing carbon dots@SiO2 photonic crystals

Particle engineering has been one of the hotspots in both stimuli-responsive and smart nanomaterials. However, efficient and facile implementation of robust covalent interaction in particle engineering remains a great challenge. Herein, we firstly propose an easy-to-perform and versatile bottom-up particle engineering strategy for covalent coupling between SiO2 particle and carbon dots (CDs) in situ. Robust covalent interactions enable the nano-micro coupling of CDs and SiO2 particles, and nearly twofold fluorescence enhancement of CDs was obtained. Moreover, hydrogen bond-driven assembly of the carbon [email protected]2 ([email protected]2) particles was demonstrated via molecular dynamics (MD) simulations, which guaranteed the high-quality colloidal photonic crystals (CPCs) without coffee ring effect. In addition, the optical coupling between CPCs and CDs ensures brighter and more saturated structural colors, as well as enhanced fluorescence for microfluidics-derived bi-optical [email protected]2 CPC supraballs. Based on this, bi-optical signal detection chip towards veterinary drug is developed. The in-situ covalent coupling strategy developed in this work might open an innovative avenue towards the particle engineering, which will also provide a methodological reference for the design of functional inorganic particles.