Raman studies on the specific adsorption of BPE with PbI2

Intercalation, the insertion of guest atomic and molecular entities into the architecture of a crystal, is an efficient route for generating new materials with novel properties. However, the detailed analysis of their new structure and properties is of great importance, which are still insufficient. Here, 1,2-bis(4-pyridyl)ethylene (BPE) intercalated PbI2 (BIP) has been investigated by Raman spectroscopy together with correlated studies of scanning electron microscope (SEM), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) absorption spectrum, and energy-dispersive X-ray spectroscopy (EDS). The Raman spectrum of intercalated compound discloses new lines at 83, 222, and 234 cm(-1) with remarkable displacement of the bands at 1001, 1200, 1603, and 1640 cm(-1), indicating a formation of a new crystal and the chemical interaction between the nitrogen atom of guest molecules with PbI2 host material. XRD confirmed the intercalation of guest molecules into a host matrix through the appearance of diffraction lines at lower angles that are corresponding to the enlarged unit cell in c axis. Furthermore, we also found that the PbI2 can specifically adsorb of BPE molecules, which was confirmed by an adsorption experiment revealed by adsorption capacity toward BPE is higher than 2,2-bipyridine and 4,4-bipyridine, suggesting the good adsorptive selectivity toward BPE by PbI2 film. This work further demonstrated our mechanism on enhanced Raman spectroscopy on PbI2. It is believed that this unusual discovery not only enables PbI2 to be a specific adsorbent, which also provides a new advance toward a better understanding of structure about PbI2.

Automated summary

Intercalation of BPE into PbI2 was studied through Raman spectroscopy, SEM, XRD, UV-Vis absorption spectrum, and EDS. The results show a new crystal structure and chemical interaction, as well as specific adsorption of BPE by PbI2, indicating potential new applications and improved understanding of PbI2 structure.