Structural, electronic, thermodynamic and optical properties of SnlSemSn clusters: A DFT study

Abstract

• DFT study of electronic, thermodynamic and optical properties of SnlSemSn clusters. • Band gap energy of Sn l Se m S n clusters lie in the semiconducting range (1.035–3.463 eV). • Sn 1 Se 1 S 2 is found to be the most reactive cluster. • Absorption spectra can be tailored by varying thecomposition of atoms in clusters. Density Functional Theory (DFT) calculations are performed to investigate the structural, electronic, thermodynamic, and optical properties of Sn l Se m S n clusters with the variation in the number of Sn, Se, and S atoms using B3LYP/321-G ∗ level of theory. We have obtained 23 optimized clusters and their calculated properties are dependent on the size, geometry, and structure of clusters. We observed that Sn 1 Se 1 S 2 is found to be highly reactive owing to its largest values of electronegativity, vertical ionization potential, vertical electron affinity with the least values of binding energy and band gap energy. The least reactive cluster is Sn 1 Se 1 S 8 with the maximum values of band gap and hardness. The band gap energies of all clusters lie in the semiconducting range (1.035 eV–3.463 eV). The optical absorption is observed in ultraviolet and visible regions. The theoretically computed absorption spectrum for excited states is compared experimentally confirming their applications in optoelectronics.