Raman scattering of hexapod-like pbs nanomaterials

A hexapod-like lead sulphide (PbS) nanostructure with six symmetric arms were investigated by Raman spectrum. The first order longitudinal optical phonons (1LO) and second order longitudinal optical phonons (2LO) vibration modes locate at 205 cm^-1 and 456 cm^-1, respectively. The transverse optical ( TO ) mode and combination modes (LO+TO and TO+TA) exist in the low frequency area. In air circumstance, the surface of PbS nanomaterials can be easily damaged by laser with power ∼1.2 mW. The vacuum circumstance can avoid from photodegradation efficiently. Therefore, both irradiation by enough power laser and oxygen condition are necessary conditions for the photodegradation of PbS nanomaterials.