The core-shell structure improving the third-order nonlinear optical response of Zintl ions: M@Sn 9 4

Abstract

The core-shell structure significantly impacts multiple material properties, yet systematic investigations into its enhancement of third-order nonlinear optical properties in metalencapsulated clusters remain unexplored. This paper explores the influence of the coreshell structure on enhancing the third-order nonlinear optical (NLO) properties of materials, focusing on the M@Sn 9 4-series compounds. By employing theoretical calculations and excited-state analysis, it is revealed that the introduction of a core-shell structure effectively improves the third-order NLO performance, with specific metals as the core demonstrating superior NLO responses due to enhanced electron transfer pathways and three-dimensional aromaticity. Notably, Pd@Sn 9 4-exhibits superior thirdorder nonlinear optical response, which is an order of magnitude greater than Sn 9 4-. These findings offer a theoretical basis for optimizing third-order NLO performance in inorganic cluster systems, with potential implications for advanced optical materials development.