Band Gap Measurement of Titanium Oxide (UV)

Photocatalysts provide catalytic effects when they absorb light and become excited. Because each photocatalyst has a characteristic band gap, they are excited in different wavelength regions. Since UV-visible absorption spectra are used to confirm the excitation wavelengths, they serve as the most fundamental of tools for evaluating photocatalysts. In this example, the band gap of titanium oxide was measured using a UV spectrophotometer. Titanium oxide, which is a material typically used in photocatalysts, has three types of crystal structures - anatase, rutile, and brookite forms. Each type has different density, refractive index, and other properties. The band gap was determined for anatase and rutile type titanium oxide powders, the types mostly commonly used for industrial applications, by measuring the diffuse reflectance.

The band gap was determined from the diffuse reflectance spectra. The Excel band gap calculation macro is used by loading spectral data, selecting [Measuring mode (Transmittance/Reflectance)] and [Value of n] (type of transition process), and then specifying the range that can be approximated as a straight line near the inflection point as the tangent line. This makes it easy to determine the band gap value using a Tauc plot.

Measurement Conditions