Band gap (Eg) calculation of UV-Vis spectroscopy from absorption spectra

[@kunsahaho607]

Why you do not use the 2.302 constant when calculating the absorption coefficient, alpha? like alpha=2.302*(absorption)/thickness.

[@mohammedessam8085]

What α would be in case of suspension not thin film? can i use the concentration in this case ?

[@amhnguyen9829]

Can you help me how to identify the semiconductors are either direct bandgap or indirect bangap? Thanks!

[@zahidurrahaman428]

Very helpful. Thank you. Keep up the good work.

[@easyedu1]

Glad it was helpful!

[@랄뚜기-q8y]

what can cause an error between the band gap calculated by the UV-vis spectroscopy and the PL specatra analysis

[@easyedu1]

there are so many factors, first most of the peaks in PL are not because of band gap some are due to band to band transition while from UV-vis there are different values of n for direct and indirect, allowed and forbidden transition, but the band gap calculated from UV vis is more acceptable.

[@AK-qo6vw]

Thanks... much needed.

[@easyedu1]

You're welcome!

[@activ1026]

thank you for your help much appreciated.

[@easyedu1]

you are most welcome

[@bhushanblog8898]

to calculate the value of alpha, in any compound like AgBr can we take thin film thickness value 500 nm or it varies, if it varies then what will be the possible value of thinfilm thickness in case of AgBr?

[@easyedu1]

Thickness is related to material use beer lambarts law for absorption coefficient calculation.

[@md.sydulislam4362]

Hi, so far i know adsorption coefficient, alpha= 2.303 (A/t)... so where is 2.303 value in your case??

[@MrApplehair]

Videos closed the final result. What was it?

[@pny8598]

Send some uv data for practice to plot multiple graph in origin

[@huyenlaithingoc5327]

can I use the absorbance like the alpha if I don't know thickness of thin film

[@easyedu1]

Use beer Lambert's law for calculation of absorption coefficient

[@huyenlaithingoc5327]

I had the answer. Thank u so much

[@simplychemistry9679]

@@easyedu1 Can you please help me how to do it?

[@achmadnasyori8667]

​@@huyenlaithingoc5327 Hay, What is your sample (Liquid, Gass or solid) ?

[@thanhmiennguyen895]

Thank you so much. That's helpful with me.

[@easyedu1]

you are most welcome

[@iamalbana8930]

Can you make another tutorial like this using kubelka munk method?

[@easyedu1]

I will try.

[@iamalbana8930]

@@easyedu1 thank you, i'll wait for it

[@muhammadim1575]

I also want tutorial by using kubelka munk

[@easyedu1]

@@muhammadim1575 video is avilable on this channel about kubelka munk which almost similar to this the only difference is absorption coefficient = F(r) = k/s

[@komalkhalid1681]

what will be thickness in case of suspension of nano particles

[@easyedu1]

just measure for reflectance data or uv vis

[@saulmorales8169]

Hi! How can I measure reflactance in the case of a nanoparticle solution? and by the way thanks for the video

[@buutonthat3930]

@@easyedu1 i have the same questions, can u explain for me. Thank u

[@sohanahmad2593]

Can you please tell how do you calculate absorbance?

[@easyedu1]

You can calculate absorbance and transmittance spectra for you sample by using UV vis spectroscopy technique , this is a characterisation technique use for calculating absorbance transmittance and reflectance of the sample

[@sohanahmad2593]

@@easyedu1 Dear Sir, would you please tell me which software do you use for getting absorbance data? I used gaussView software, and I have UV-VIS spectra data. But dont know how to get absorbance data. Thank you.

[@shreeniketjoshi]

Hello, can you please provide a reference for Alpha = Absorbance/ Thickness..I want to cite it for my project. Thanks a lot!

[@easyedu1]

alpha=2.303(A/Thickness) for getting this equation you need to solve beers Lambert's law, optical properties of solid mark fox book and search for publication this is a common equation available in most of publications.

[@keerthanat1627]

I want to calculate energy gap of biosynthesised zinc sulphide...can i use this method...in that case should i take the average grain size from xrd as thickness... Plz reply...thank you..stay safe...

[@keerthanat1627]

@@easyedu1 can i use this to calculate Eg of biosbiosynthesised ZnS..

[@Mynameisnotbilbo]

I have read this book, there is nothing like that equation mentioned in there.

[@MoonLight-rq1nh]

?

[@jiths-fv2gl]

does it have there many absorption coeff value. in what case we consider single absorption coeff value. please comment.

[@easyedu1]

different materials have different absorption coefficient value.

[@haiderumran5752]

Thanks a lot, very helpful

[@easyedu1]

You are most welcome

[@sanaamin202]

Ap nae band gap latae time linear portion kyn lia????

[@adilbasoglu7046]

In fact thickness should be taken in cm. 500x10^(-7) cm. But taking as meters does not affect the band gap value

[@easyedu1]

wave length is in nano meter

[@success7669]

from where we got the thickness and is it the same for all calculation ?

[@success7669]

@adilbasoglu7046 from where we got the thickness and is it the same for all calculation ?

[@live4Cha]

thanks very helpful

[@easyedu1]

You are most welcome

[@swagatalaxmipujaru2440]

what is the thickness here?

[@easyedu1]

Thickness of thin films used for absorption coefficient calculation.

[@athithyas4999]

what is 500nm thickness

[@easyedu1]

It's thickness of thin films.

[@utaiyachandran]

@@easyedu1 I am using nanomaterials. how to substitute values

[@cheesemasterlord41]

What are the units for hv?

[@easyedu1]

hV is in e.v where hc= 1240 e.v nm

[@hajatar7913]

thank you

[@easyedu1]

You're welcome

[@shaswatvikramgupta]

How will we get thickness

[@easyedu1]

Use use invelope technique of calculating thickness from transmittance data a video is available for thickness measurement in this channel or if you have reflectance data from DRS than use kubelka munk function which is almost similar to this method the only difference is absorption coefficient in drs we use kubelka munk function which is equal to k/s a video is also available in this channel about kubelka munk band gap measurement

[@shaimbox8552]

How can i calculate those two columns ( wavelengths and absorbance )? Please help .

[@easyedu1]

Shaim Box by UV-vis spectroscopy. That is the absorbance data and is calculated by Ultraviolet Visible spectroscope .

[@shreeniketjoshi]

what is 1240?

[@easyedu1]

Product of planks constant and speed of light hc

[@shreeniketjoshi]

@@easyedu1 Hi, thanks! What are the units for planks constant? Because in eV the product should be 1.2 *10e-6

[@easyedu1]

@@shreeniketjoshi ev.s unit of planks constant speed of m/s and use wavelength in nm and energy in ev , planks constant is = 4.1357*10^-15 ev.s

[@shreeniketjoshi]

@@easyedu1 Perfect that makes sense! I have one last question, shouldn't speed of light be considered inside the film by using refractive index?

[@easyedu1]

We are not calcuting the speed of light here we are dealing with absorption the amount of light absorbed by the material and for that we are taking absorption coefficient.

[@ZafarAli-pm4dz]

its not perfect.

[@easyedu1]

Kindly mention the recommendations for perfection.