This study shows the presence of surface-enhanced Raman spectroscopy (SERS) effect caused by Ag2Se quantum dots embedded in the zeolite matrix. The quantum dots that were synthesised and stabilised in the matrix of F9-NaX zeolite show a size of 5 nm and a quasi-spherical morphology. The calculated interplanar distances confirm the presence of quantum dots in cubic phase Im-m. We suppose that the in situ SERS effect in the material is caused by chemical-enhancement mechanism (CEM). The density functional theory (DFT) is undertaken to corroborate our hypothesis. The structure H8Si8Al8O12 represents the zeolite cavity unit, and small clusters of (Ag2Se)n represent the quantum dots. Both structures interact in the cavity to obtain the local minimum of the potential energy surface, leading to new molecular orbitals. After the analysis of the predicted Raman spectrum, the Raman bands increase significantly, agreeing with the experimental results at low wavenumbers in F9-NaX zeolite. [Figure not available: see fulltext.]
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- Chemical-enhancement mechanism in quantum dots
- DFT SERS calculations
- SERS in zeolite