Preparation and optical properties of hexagonal and orthorhombic molybdenum trioxide thin films

摘要

h-MOO_3 and α-MoO_3 films were successfully fabricated on glass substrates by two ways: ion exchange and chemical deposition. The as-synthesized products were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical properties of MoO_3 films were investigated in detail. The result showed that h-MOO_3 film possesses two fluorescence emission peaks at 440 and 630 nm, but α-MoO_3 film just possesses one at 440 nm. The emission peak at 440 nm might come from the band-to-band transition of MoO_3, and the emission peak at 630 nm probably originated from the presence of oxygen vacancies in h-MoO_3 film. The photochromic behavior of the as-prepared films was also observed, in which h-Mo03 film exhibited higher photochromic response than α-MoO_3 film. It was related to some defects of oxygen vacancies in the especial h-MoO_3 structure.