SnS 纳米片层间耦合增强导致高频 Ag 和 B3g 模式的产生

The generation of high-frequency (>90 cm−1) Ag and B3g modes is due to the presence of intra-layer chemical bonds and inter-layer Van der Waals forces, and the strong interlayer coupling induced by the lone pair of electrons of Sn2+ in SnS. With the increasing number of SnS nanosheets, the interlayer coupling caused by Van der Waals interaction and other reasons increases with the density of SnS molecules and Sn2+ along the b axis and its corresponding bond angle, which leads to the increase of restoring force and thus the decrease of phonons associated with the Ag1 and Ag2 vibrations along the b axis and the B3g vibrations along the zigzag direction (c axis).