Theoretical investigation on the adsorption of melamine in Al12/B12-N12/P12 fullerene-like nanocages: a platform for ultrasensitive detection of melamine

Surface-enhanced Raman scattering is a tool for improving the Raman signal of biomolecules using nanosized metal substrates. Nanomaterials such as nanocages and nanoclusters find vast applications in sensing materials, adsorption and medical devices. The characterization sensing parameters of melamine with Al12/B12-N12/P12 nanocages were investigated using quantum chemical calculations. Charge transfer from melamine (Me) to nanocage is demonstrated by Mulliken charge and natural bond orbital analysis. Furthermore, the analysis of the highest occupied molecular orbital and lowest unoccupied molecular orbital give the localization of electron density. Adsorption energies of − 115.2221, − 119.0147, − 118.8001 and − 92.8714 kcal/mol are found for AlN-Me, AlP-Me, BN-Me and BP-Me clusters. The second hyperpolarizability of all nanocage-Me systems shows very large enhancement. Melamine adsorption over nanocages causes change in electronic properties resulting in Raman mode’s enhancement and variation in chemical properties. The nanocages are cationic and melamine is anionic.