UV Vis Spectroscopy Band gap Calculator

UV Vis Spectroscopy Band gap Calculator

Absorption Peak Wavelength (nm)


Results
eV

For Tauc Plot Band Gap Calculator: Click Here...

Calculation Tutorial:

STEP1: Open the absorption graph of the material, which is obtained from the UV Vis spectroscopy. W a v e l e n g t h I n t e n s i t y 200 220 240 260 280 300 0.0 0.2 0.4 0.6 0.8 1.0 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. W a v e l e n g t h I n t e n s i t y 200 220 240 260 280 300 0.0 0.2 0.4 0.6 0.8 1.0 220 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

  1. Z H Dughaish12 January 2017 at 16:47

    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.

    ReplyDelete
  2. Kumaar Swamy Reddy B26 April 2017 at 11:46

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

    ReplyDelete
    Replies
    1. Kotta Ashique22 May 2020 at 13:22

      You should draw tauc plot for that

      Delete
    2. Unknown18 March 2021 at 00:46

      it 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%

      Delete
    3. Unknown18 March 2021 at 00:51

      it 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%

      Delete
  3. Vinil Namdev Jambhale5 October 2017 at 22:31

    How to calculate urbach energy from band gap.

    ReplyDelete
  4. Akash4 May 2018 at 13:21

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

    ReplyDelete
    Replies
    1. Chemsit balla13 June 2020 at 17:50

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

      Delete
  5. hanna3 June 2018 at 14:49

    Akash 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.

    ReplyDelete
    Replies
    1. Chemsit balla13 June 2020 at 17:48

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

      Delete
  6. raina5 December 2018 at 22:40

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

    ReplyDelete
  7. Hojjat Naji17 December 2018 at 20:50

    Hi,
    1-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.

    ReplyDelete
    Replies
    1. Unknown19 July 2020 at 22:28

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

      Delete
  8. Mr. Sumit Ramdas Patil20 December 2018 at 17:35

    Actually I want to know about the reflectance mode bandgap calculation ?
    Please specify ?

    ReplyDelete
    Replies
    1. Unknown18 March 2021 at 01:02

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

      Delete
  9. Namita21 December 2018 at 07:10

    How to calculate band gap for solid sample? Plz answer

    ReplyDelete
    Replies
    1. Saarthak kharbanda6 May 2019 at 14:55

      Melody khao khud jaan jao😂😂😂

      Delete
    2. Unknown18 March 2021 at 00:56

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

      Delete
  10. Vibhuvar patel3 January 2019 at 16:00

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

    ReplyDelete
  11. Sharanya Shree12 February 2019 at 09:55

    What is the formula for calculating bandgap from PL Spectra

    ReplyDelete
  12. Unknown1 July 2019 at 19:38

    How to calculate nanoparticles size through band gap energy

    ReplyDelete
  13. Unknown30 October 2019 at 16:59

    Very good app on mobile and can i download on laptab

    ReplyDelete
  14. Unknown30 October 2019 at 16:59

    Can i download on laptab

    ReplyDelete
  15. josen26 May 2020 at 12:23

    Kindly attach Bandgap energy excell sheet.

    ReplyDelete
  16. Unknown16 June 2020 at 12:10

    Band gap energy

    ReplyDelete
  17. Unknown25 August 2020 at 21:12

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

    ReplyDelete
    Replies
    1. Unknown18 March 2021 at 00:59

      No you can't
      you can do it from the PL data only with help of absorption coefficient because your sample is opaque.

      Delete
  18. Anonymous21 October 2020 at 11:14

    this calculation using tauc plot method?

    ReplyDelete
    Replies
    1. Unknown23 January 2021 at 00:50

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

      Delete
  19. Unknown2 November 2020 at 14:20

    thank you

    ReplyDelete
  20. Unknown21 December 2020 at 00:53

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

    ReplyDelete
  21. Unknown20 January 2021 at 17:45

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

    ReplyDelete
  22. ISHFAQ CHOHAN22 February 2021 at 13:49

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

    ReplyDelete
  23. Unknown1 April 2021 at 16:27

    how to calculate this optical band gap for porphyrins

    ReplyDelete

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