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- เผยแพร่เมื่อ 26 ต.ค. 2018
- #NanoWorld,
Attention Please: Before watching this video, please must watch this video
• Band gap energy (Tauc ...
UV-Vis absorption spectroscopy is a powerful tool use for the characterization of optical properties of nano-materials. Here in this video, I have calculated the optical band-gap energy of anatase Pure Titanium dioxide (TiO2). If you have any questions or need any help, just comment below.
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I would like to thank you for taking your invaluable time out of your schedule to record this priceless video. I really appreciate it.
Please also do for the Gas sensing and Photodetector measurements also, because it's being a hot topic nowadays. Thank you so much for this video lecture.
thank you so much,
I am very grateful to see this,
and keep posting.
Thanks alot this video just made my day. Won't need to go seniors again n again.
You are right
Thank you very much for uploading this video... Very helpful...
Thank u gentleman, amazing explanation those who r starting and doing research work in critically, and can u explain about electronic transition using spectrum, which will most helpful for us thank u
U r doing a great job. I need EIS and MOTT SCHOTTKY analysis by using ZSimpWIN software. Please add it. Along with that please try to add characterization of TEM also. Then there won't be any need of going to seniors again and again. Thanking you.
The uploaded video is really explained well. Can u please upload for FTIR spectroscopy. It will be helpful for all of us.
Well explained video ! Thanks (y)
Hi nice work! Why the square power in the 4th col?
Ps: You earned a sub bro! Keep up the good work and thanks!
Very useful video! thx!
Very helpful. Thank you. Keep up the good work.
Thanks, will do!
A nice and easy way of calculating a bandgap. My question is that can I used it for a powder DRS result?
Truly helpful, many thanks!
Glad it was helpful!
Thank you for this video. Can u please share, video on absorption edge using absorbance data....
Thank you so much for this video sir.
useful video.Thank you
Thank you so much, but i have a question pls. I noticed the formula you used for the y-axis of the Tauc plot, you didn't consider the thickness of the material. is thickness not needed to find the absorption coefficient (alpha)?
Thank You very Much...
Thank you so much.
Excellent
Very useful video. May I ask question? Here it is: I have absorbance data of my sample. I try to find transmittance by using formula T = 1 - Absorbance. But I found some negative values in the results. What do you think about it? Do you have some advice or tricks for this case? Thanks.
Very much informative video
Heartly Thanks ❤
Thank you too
Thank you for neat explanation....
your are welcome.
thanks a lot .
Thank you so much
THANK YOU SO MUCH. But i think you should divide in the thickness of your samples when you calculate the coefficient alpha
Hello bachchar Hadrane! Thanks for the comment.
Why should i divide in the thickness? Can you explain it please.
@@nanoworld6122 theoretically, the beer lambert law say that I=I(0) exp(-alpha*d) where d is the thickness. so after mathematic reasoning we find : alpha = -log(I/I(0)) * ln(10)/d and -log(I/I(0))= A the absorbance and ln(10)=2.303. that's why we should divide by d the thickness.
And pratically, the standard thickness of the most sample tanks used in IR devices is of 1cm . so i didn't know it before writing this comment. so we can do easily what you did.
@@bachcharhadrane3675 hi. what if my sample is powder and not a thin film? how do I consider the thickness then?
Very usefull
thank a lot
hi nanoworld this video helped me a lot
can u please do a tutorial on how to determine the phases of xrd or how
to analyse xrd data i am a begineer and having problem with it
samw question i have
Very helpful thanks a lot....can u plz answer how to find extinction coefficient from abdorbance data
Thanks for making the video.
I have a question. Why did you just draw a tangent by hand instead of making origin do it for you using numerical extrapolation? The way you did it was wrong my friend.
Thanks for comment.
I would like to know what concentration I am supposed to use for doing the UV-Vis spectra. Very helpful video anyway
Nice
Thanks a lot for nice video
Most welcome
Thanks so much
You're welcome!
could you make a video describing how to obtain index of reflection from reflectance spectra?
Thanks alot, but i would like to understant when calculating (ahv) why did you raise it to power 2 when setting the F(x)?
Thanks for comment. here is the answer of your question, please completely watch this video. if still have confusion, then feel free to ask.
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
Thanks for comment. here is the answer of your question, please completely watch this video. if still have confusion, then feel free to ask.
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
thanks so so much!! does the concentration effect the band gap? sorry if the question is funny :/
Also, how about if we have more than one curve.is the band gap will show different peaks, should we consider the first? . Thanks
Yes, only If the concentration is too low or too high. In these causes, the material will not obey the Beer lambert's law and as a result will give you wrong value of the bandgap energy.
You have to consider the maximum absorbance band, the other lower absorbance band at higher wavelength might be due to trapped states in between conduction band valance band.
Thank you Sir,
All is good, but please mention that alpha=2.303*A/d where A=absorption and d= path length of cuvette (10 mm or 1cm) OR thin film thickness
Yes, you are right
hi!
does this mean I should consider "d" as path length of cuvette if my sample is a powder and not a thin film?
What is the role of thin film thickness in the Tauc plot?
Very interesting. Some bibliographical reference that you can recommend me
I have TiO2 thin film can I calculate direct energy gap by this method
When convert the unit of x axis from wavelength to Energy (eV), the values of y axis also need to be converted due to E equals hc/lambda, it's inverse proportion.
I make the unit conversion accurately. Here is a detail video, you must watch it.
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
y is the absorbance fraction
Anyone tell me where to get those x and y values?
Is there is no need to take the thickness t while calculating absorbance coefficient
Hi, can I use absorbance data from FTIR to calculate band gap?
Thank you soo much for this helpful video. can you send me this video as a word file, please?
So nice to find the useful video. My issue at this point is: I do have transmittance data, how to find the band gap? Condition is I do not have thinness of the film too. Is it possible to solve this problem?
No you need the thickness of the film, you'll calculate alpha=1/d Ln(1/T)
and same steps you'll draw alpha ×h×u = f(hu)
If I do a single nanowire absorption measurement, is it still possible to use the shown equations? even though I am not using a cuvette? I wonder how to calculate the absorption coefficient of a nanowire from the absorbance spectrum.
Honestly speaking, I don't think, I'm able to answer your question properly and I don't want to misguide you. Anyway, follow this link and also check the cited references of this proposal, if necessary,
www.sns.it/sites/default/files/allegati/2019/06/phd_topic_lyon_0.pdf
I read it a few months ago. In this proposal, they discussed and mention the technique of absorption of a single nanoparticle.
Maybe, this proposal will help you.
This data is of powder sample or thin film?
Hay, Could you tell me about 1240 and 2.303.
Very usefull video thank you but i have few questions. Is this graphic for anatase or brookite? Its known that anatase TiO2 has indirect band gap. Than we have to use 1/2 for square in formulations. Am i wrong and the other question can we use tauc plot for indirect band gap graphics thank you.
Hello mnebi!
The data which i used in this video is Anatase phase of TiO2.
Yes, you are right, Tauc Plot could be used for estimation of direct as well as indirect band-gape energy. All you need is to use square for direct band-gap and 1/2 for indirect in this formulation.
Yes, Anatase is indirect band-gap semiconductor. But in some research paper, It is also reported that Anatse TiO2 showed direct band-gap behavior. Our synthesized Anatase TiO2 is direct band-gap. As we plotted it for both direct and indirect, what we find is the curve didn't fit for Indirect band-gap value, however it is fit very well for direct band-gap energy.
@@nanoworld6122 Thank you for enlightening information. I'il look forward to your new videos.
what point did you pick to draw the straigth line
Kya sirf nano materials ka band gap nikal skte h is method se????
start at 5.45 to see the tauc plot
Please do a video on photoluminescence spectroscopy
Noted, Thanks
It was helpful. But how do we know that our material has direct or indirect band gap? Is there any way to find out the type of band gap from the raw data?
Yes, from this method (shown in the video) you can know the nature of your material either it is direct bandgap or indirect bandgap. I'll make another video on it.
But at the moment, if you are facing difficulties than send me your data at fascinatingNanoWorld@gmail.com, I will help you. Thank you.
thank u mate
however i would like to know whether u treat absorbance (a) and absorption coefficient (alpha) the same bcz it seems like for tauc plot ordinate u are using (ahv) instead of (alpha hv).
No, Absorbance and Absorbance coefficient are two different things. Please watch the video carefully you will understand I'm NOT treating them as same.
Thank You
@@nanoworld6122 Yes, these two are different and we can see the same in the video. I am little worried whether it is 'Absorbance coefficient' or 'Absorbtion coefficient'? Thanks.
Could u enlight me, what is the value of column C(X2) in F(x) row? Thanks.
Very useful video.
In C(X2) column, I put energy conversion formula in F(X).
F(X) = 1240 divide by wavelength (column).
here is a detailed video on this.
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
@@nanoworld6122 thx 4 ur response.
Great video! Could you show the reference for this method?
This method is widely used for UV-Vis Absorption spectroscopy, here is a reference for this method.
doi.org/10.1007/s10854-018-9670-3
Could you please tell the origin version used here
Tank you plais can u explain mor touc équation
can you plz make video on how to determine rate constant of dye degradation on origin from lnC/Co vs time please please
I need it also, do you know hot? can you xplain me please?
@@victorruiz4331 take absorbance spectra of ur sample divide initial absorbance over final of different time period. then take ln of it and plot wrt to time
Aisha khan I thought that the concentration obtained from the calibration curve, then the constant is the slope of Ln co / c. vs time.
Can you please tell me how to plot bandgap every spectra of multiple result in one graph like for series of sample..
I will upload a video on it
Thank You
My origin version doesn't have the F(x) column available like yours. Can you guide me how to insert it? Thanks
Same. Can u got F(x) now?
10.36, you have changed ahv to( ahv)2 directly but it is graph between ahv and hv only, I am in doubt,
Some biblical reference to quote it in my thesis, please.
why you multiply 2.303 in the last column
you must consider watching this video
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
can anyone tell me how did they export that graph to another one? please reply soon I'm in need urgently.
Just press "control + C " button in your key board. and "control + V" where you want to past it.
What is last column
please tell me how u are calculate the alpha without knowing the thickness of the sample.
watch this video
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
here is the answer of your question
can the same method be used for glass samples also
Yes you can!
Hi thankyou, why 2.303?
Hello, watch this video,
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
hello,can you give us play Mott-Schotty?
How can i create those two columns (absorbance and wavelengths) ? Please help .
Do you have your data?
@@nanoworld6122 Thanks for the reply . I don't have the data . How can i acquire data for ZnMgO ?
this for direct or indirect
This is for direct
Sir how to find those absorbance and wavelength values?
by UV-vis
From where did the value 2.303 came? Kindly elucidate.
Hello Rosa indica! You must watch this video.
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
2.303.is wat value please replay. It is for powder sample
Watch this video
th-cam.com/video/tbyJjCMkDtc/w-d-xo.html
For a powder sample, how to find Eg value using tauc method?
You can calculate it using Kubelka-Munk function
@@nanoworld6122 thank you
can u do a video on photoluminescence plot analysis
i will try to add a video soon.
@@nanoworld6122 Waiting for that too.
is this Kubelka-Munk plot??
Kubelka-Munk Vidoe is there,
th-cam.com/video/Ry9Jdjeh2-Q/w-d-xo.html
is it the same for reflection data?
No, the method for plotting of DRS ( Diffuse Reflectance Spectroscopy) data is a little bit different.
NanoWorld will you please help me ? Video, links,papers anything
@@bestrong6517 Video for the reflectance spectroscopy will be uploaded soon.
NanoWorld Thank you so much ❤️I can’t wait to watch it .
Here is your demanded video,
th-cam.com/video/Ry9Jdjeh2-Q/w-d-xo.html
Teasable noise in the background is really unwanted. could u please remove it. Thanks. Anyhow, great job.
Thanks for your suggestion.
How to convert absorbance spectrum to CIELab values? If anyone know, please suggest me any link to a detailed method
formula CIELab is from tristimulus values (X Y Z), you can read "AATCC Evaluation Procedure 6-2008" , while XYZ is a function of reflectance, ( I dont know the detail but you can read "ASTM E308" and small information in "A New Method for Computing Optimum Weights for Calculating CIE Tristimulus Values"
Hello ,thin film ka band gap bhi ese ni nikalna h
Yes
@@nanoworld6122 isme film ke thikness ki need nhi hogi
@@nanoworld6122 ????
I think this is not right way to draw line directly and touch to x-axis after plotting tauc plot, first you should choose two points from linear region and then by taking slope you can draw line
Thanks for the suggestion.
Hi, I would like to know where or which tangent line I must draw in my graph www.pastepic.xyz/image/tauc-plot.PRif4 in order to obtain the band gap. Thanks in advance!
The one, which in near 3 eV.
@@nanoworld6122 thank you for your time and for both videos!
Thank u but ur formula seems wrong. It missed thickness
There are a lot of unnecessary things that you have showed. This video coupd be 5 minutes long.
Thanks for suggestion.
But, it is so helpful for beginners...