# UV Vis Spectroscopy Band gap Calculator

## UV Vis Spectroscopy Band gap Calculator

#### Calculation Tutorial:

**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.

## Post a Comment

This is the useful and usual formula used to calculate the energy gap from the absorption spectra in the visible and ultraviolet regions and infrared region as well. This calculator which is given here will help the researcher to find directly the energy gap Eg.

ReplyDeleteWhat if my sample has two absorption peaks or no peak at all? How do I calculate my bandgap?

ReplyDeleteYou should draw tauc plot for that

Deleteit means your sample is not single phase, its amorphous part shows one indirect band gap and partly crystalline pary has another direct band gap.You should report it as such. 2ndly might be your dopant is not uniformly distributed in the sample due due to low mol%

Deleteit means your sample is not single phase, its amorphous part shows one indirect band gap and partly crystalline part has another direct band gap.You should report it as such. 2ndly might be your dopant is not uniformly distributed in the sample due to low mol%

DeleteHow to calculate urbach energy from band gap.

ReplyDeleteI can't understand how to calculate FWHM using xrd. Can u explain briefly using xrd graph without using any software?

ReplyDeleteHi, How do I calculate the gap energy from XRD results?

DeleteAkash the FWHM is very easy by using origion software for your XRD spectra.when you draw your xrd data in origion then make one peak zoom go to analysis then peak and base line then multiple peak fitting then open dialog change the gauss to gaussian then click ok a side window will open then open fitting a full history of the peak will appear then you can find the FWHM value of your peak in paprameters.

ReplyDeleteHi, How do I calculate the gap energy from XRD results?

DeleteWhy the absorbance decreases at shorter wavelength (200-217nm)?

ReplyDeleteHi,

ReplyDelete1-open your XRD pattern by X'Pert High Score,

2-push right click bottom on the pattern and then select search peaks.

3-again push right click bottom on the pattern and choose the label peaks,

4- active FWHM option,

5- now you can see the FWHM value for each peak in your pattern.

note that; in this method the FWHM unit shown in degree. if you want to calculate crystallite size or lattice strain, you should convert it to Radian.

hey do you have link to download X'pert highscore ?

DeleteActually I want to know about the reflectance mode bandgap calculation ?

ReplyDeletePlease specify ?

you write IH model in origin software and get band gap with absorption coefficient.

DeleteHow to calculate band gap for solid sample? Plz answer

ReplyDeleteMelody khao khud jaan jao😂😂😂

DeleteUse IH model on your PL data and calculate band gap with help of absorption coefficient using values of S between 2 to 8.

DeleteGreat explanation of uv vis spectroscopy. It would be Helpful for many students

ReplyDeleteWhat is the formula for calculating bandgap from PL Spectra

ReplyDeleteWhich is this direct or indirect?

DeleteHow to calculate nanoparticles size through band gap energy

ReplyDeleteVery good app on mobile and can i download on laptab

ReplyDeleteCan i download on laptab

ReplyDeleteKindly attach Bandgap energy excell sheet.

ReplyDeleteBand gap energy

ReplyDeletevery useful site, if i may ask, is their a way to calculate band gap energy of nanopowder from XRD data? thanks

ReplyDeleteNo you can't

Deleteyou can do it from the PL data only with help of absorption coefficient because your sample is opaque.

this calculation using tauc plot method?

ReplyDeleteHow to make tauc plot method to calculate band gap energy?

Deletethank you

ReplyDeleteThanks a lot. Really this is very helpful for me.

ReplyDeleteit helps me a lot (very useful). Thank you so much

ReplyDeleteHow it differs from DRS (Diffuse Reflectance Spec.)????

ReplyDeletehow to calculate this optical band gap for porphyrins

ReplyDelete