Highly sensitive and reproducible SERS substrates based on a novel 3D waffle-like PMMA-CsPbBr3-Au ternary film

s The development of a highly sensitive and reliable surface-enhanced Raman scattering (SERS) substrate is crucial for overcoming the limitations in its practical applications. Herein, a novel 3D waffle-like SERS substrate with high activity is constructed for detecting trace amounts of myricetin in complex analytes extracted from green tea. The substrate is achieved through a layered ternary film structure, where ordered poly (methyl methacrylate) opal photonic crystals (PMMA OPCs) serving as a 3D hot spots template and enhancing the performance of CsPbBr 3 film that facilitates efficient charge transport, and an Au film covered over the CsPbBr 3 film modulating the vibronic coupling and providing plasmonic hot spots. The PMMA-CsPbBr 3 -Au substrate exhibits a low detection limit of 10 −10 M with an 8.9 × 10 7 enhancement factor, signal repeatability and stability for R6G molecules. Furthermore, the SERS detection of myricetin content in Longjing green tea from different years is carried out, and the results show a good linear positive correlation with storage years (R 2 =98.2 %), demonstrating the potential application of 3D substrate for sensitive and reproducible SERS.