Estimate the energy band gap using Tauc's Equation from UV-vis spectroscopy data via origin soft.

UV-Vis spectroscopy is an analytical technique that measures the amount of discrete wavelengths of UV or visible light absorbed by or transmitted through a sample in comparison to a reference or blank sample. This property is influenced by sample composition, potentially providing information on what is in the sample and at what concentration. Because this spectroscopy technique relies on the use of light, we first considered the properties of light.

Light has a certain amount of energy that is inversely proportional to its wavelength. Thus, shorter wavelengths of light carry more energy and longer wavelengths carry less energy. A specific amount of energy is required to promote electrons in a substance to a higher energy state, which can be detected as absorption. Electrons in different bonding environments in a substance require a specific amount of energy to promote the electrons to a higher energy state. This is why light absorption occurs at different wavelengths for different substances. Humans are able to see a spectrum of visible light, from approximately 380 nm, which we see as violet, to 780 nm, which we see as red.1 UV light has wavelengths shorter than that of visible light to approximately 100 nm. Therefore, light can be described by its wavelength, which can be useful in UV-Vis spectroscopy to analyze or identify different substances by locating the specific wavelengths corresponding to the maximum absorbance (see the Applications of UV-Vis spectroscopy section).