Self-assembled zeolitic imidazolate framework-8/Ag nanoparticles composite with well-controlled flower-like architectures for ultrasensitive surface-enhanced Raman scattering detection

The performance of surface-enhanced Raman scattering (SERS) active substrates highly depends on its structure and components. Herein, for the first time, a novel zeolitic imidazolate framework-8 (ZIF-8)/Ag nanoparticles composite with flower-like architecture is demonstrated. By using tannic acid as structure-directing agent, well-controlled flower-like ZIF-8 could be obtained. Through in-situ reduction, Ag nanoparticles with uniform grain distribution were directly grown on the surface of ZIF-8 nanosheets. The synergy effects of preconcentration and plasmonic hot spot allow the picomolar detections and high reproducibility of the SERS method. As a result, the minimum detection limit of rhodamine 6G can be as 10⁻¹⁴ mol L⁻¹ and the stability and repeatability are satisfactory. This work provides a facile and general method to develop plasmonic ZIF-8 hybrid with controlled morphology for potential applications in bioanalysis, chemical sensing and catalysis.