Photoluminescence enhancement of carbon dots induced by hybrids of photonic crystals and gold–silver alloy nanoparticles

Abstract

Carbon dots are attracting worldwide interest owing to their unique optical properties and great potential for application. However, orange/red emission carbon dots are still rare and exhibit relatively low efficiency. In this work, we present a novel strategy to enhance the fluorescence intensity of orange carbon dots, by synergistically manipulating an electromagnetic field through opal photonic crystals and the localized surface plasmon resonance of a metal structure. An optimum intensity enhancement of 25-fold was obtained for a modulated sample of PMMA opal photonic crystals and 53-fold for PMMA opal photonic crystals/Au–Ag alloy plasmon hybrids. The local electromagnetic field distribution for the PMMA opal photonic crystals/Au–Ag hybrid is calculated by the finite difference time domain method. Furthermore, a fingerprint identification system based on synergistic modulation is realized in the composite system, which provides novel insights into the potential applications of carbon dot films.