UV Vis spectroscopy band gap calculation
Wavelength of Absorption Peak (in nanometer)
STEP1: Open the absorption graph of the material, which is obtained from the UV Vis spectroscopy.
STEP2: Now zoom on the area for which you want to calculate the band gap and note down the wavelength (λ) at which absorption peak is shown.
STEP3: Now enter the measured wavelength value (eg. 31.8) into the ” Wavelength of Absorption peak (in nanometer)” column of the calculator. You should get the calculated results of the band gap in the “Calculated Result” field.
Theory Behind Calculations:
- UV Vis Spectroscopy absorption peak means the Electrons are absorbing the Energy at some specific wavelength.
- Electrons are absorbing Energy means the Electrons are going to excited state from its ground state.
- Electrons are going to excited state from its ground state means the material is having band gap, thus which can be determine by absorption wavelength.
Energy Equation of Quantum Mechanics:
Energy (E) = Planks Constant (h) * Speed of Light (C) / Wavelength (λ)
Where, Energy (E) = Band gap, Planks constant (h) = 6.626×10^-34 Joules sec, Velocity of Light (C) = 2.99×10^8 meter/sec and Wavelength (λ) = Absorption peak value. Also 1eV = 1.6×10^-19 Joules (Conversion factor)
By this formula band gap can be calculated easily, from UV Vis spectroscopy absorption peak.