Photoinduced degradation of organic dye over LiBiO₃ under illumination of white fluorescent light

We report dye-degradation effects of a semiconductor LiBiO₃ revealed under illumination of a conventionally used white fluorescent light. Optical absorbance spectra of LiBiO₃ were broadened so smoothly, with the absorption edge penetrated to around 730 nm, that the material was able to absorb a wide range of visible light. Results showed that solution of a standard dye, methylene blue, was degraded completely after 4 h illumination. Furthermore, the value of total organic carbon decreased 70% in the decolorized solution, suggesting that the molecular form of the original methylene blue was mineralized effectively to nonorganic fragments by the photoinduced oxidization effect. Moreover, the wavelength dependence of apparent photonic efficiency was evaluated using a standard Xe lamp coupled with monochromatic filters. These results were interpreted from the viewpoint of this material’s electronic structure.