Thank you so much, I also made a quantum dot of graphene by cutting it from supercell of 5x5x1. And then saved it . It is showing the lattice parameter a=b=12.3nm which is 5x2.46nm. I'm very confused about these parameters. Should I replace these with 2.46nm which is experimental value of lattice parameter of graphene. Please reply, I'm very confused.
Quantum dot should have vacuum space around it, so you will need a larger lattice. The lattice should be large enough such that your structure and vacuum and present in it
Thank you so much. I think a vacuum of 20nm in all directions should be sufficient. How I make clear that QD lies within this region, I think the size of QD should be very small compared to this vacuum. Please tell me whether I'm right or not? Your help is very appreciable. Again thanks.
@@Priya-gr9ee 20 angstroms is fine - not 20 nm. 20 nm is equal to 200 angstroms - and that’s far too large. You can center the dot to the center of the unit cell through some linear algebra to the atomic coordinates, in which ever programming language you prefer
Thank you for your tutorial. Could you exlplain how to build a supercell made of this QD and and some vacuum between the QD's facets and the supercell's boundaries?
I would like to ask you a question about generating the QD of alpha-sulfur. If you could explain, the QD generated from this method does not look correct to me for sulfur.
What are the lattice parameters for this QD? I did for SnO2 tetragonal structure and VESTA shows a=b=c=1.0. Is right? Finally, are the atomic positions in cartesian coordinates? Thanks.
The coordinates depend on how you save them. If you save as xyz I think they are Cartesian. If you save as a vasp you have option of direct or cartesian. The quantum dot has no lattice - it is a cluster model. Just save it as a .xyz file, and you won’t have to worry about lattice parameters
Thanks. I have and it’s tough. There are a few ways to do it. The easiest is to cut out a spherical center in the shell structure and place a QD in it. Then, only leave 1-2 layers of shell followed by a geometry optimization.
@@nickelandcopper5636 Hi, thanks for the reply. It seems similar to what you did in the Pt@Pd video (if i remembered correctly). I guess, the challenge is how to construct the interface binding structure. Still unclear to me. Anyway, your videos are really helpful. Thanks for the sharing these!
Very good. I have subscribed to your channel. Can we make a similar QD , say for CdS, or perovskite etc.? and what will be the difference we need to follow for multi element QDs?
I have one for CdSe and graphite. For the binary or ternary QDs, you will have a broken stoichiometry. When the stoichiometry is preserved you have a special case called a magic cluster. This however would need simulated annealing to make and cannot be made solely by cutting the crystalline structure. In other words, you would need to do some form of structure optimization to get the magic clusters. Cutting the bulk crystal to get a quantum dot where all atoms are bonded fully you will break stoichiometry. In the CdSe case I show, I think it is Cd rich
Thank you sir for replying, your responses give me courage and are very helpful. Till now, I thought photoluminescence is a experimental phenomenon and can not be find out theoretically. Do you know someone who is calculating the same using DFT or provide me reference. Also, if you don't mention, it will be very helpful if you give your email address so that it will be easy to communicate and discuss about some problems.
@@Priya-gr9ee sure. At this point your best course of action will be to go to Google scholar and search “photoluminescence density functional theory” and collect 10-20 references. Read the sections of those papers where they explain how they calculate this property. Also spend time just search around Google for discussion forums. This type of searching is very important, and should be done carefully. Spend up to several weeks carefully doing it. It may seem like a waste of time but actually it sets a proper foundation for your future work. There is a famous saying that 1 day in the library (reading literature) is worth 1 week of work
It is advisable. Use your best judgement though for the final product. Always compare with the available literature if you can. If not, then be prepared to argue why you should be using what you get. This process should work for a quantum dot of crystalline bulk carbon
Really helpful video. I really appreciate your work. I will share it with my research team members. Don't stop making these videos!
Так понятно, и у вас классный английский и голос приятный :) Спасибооооо from Russia
Very helpful. Could you prepare a video demonstrating modelling of core-shell nanoparticle?
Thank you very much.
Amazing!
Thank you!
Thank you for this tutorial. I would just like to know please if there is any possibility to hydrogen passivate the dangling bonds with VESTA?
Thank you so much,
I also made a quantum dot of graphene by cutting it from supercell of 5x5x1. And then saved it . It is showing the lattice parameter a=b=12.3nm which is 5x2.46nm. I'm very confused about these parameters. Should I replace these with 2.46nm which is experimental value of lattice parameter of graphene.
Please reply, I'm very confused.
Quantum dot should have vacuum space around it, so you will need a larger lattice. The lattice should be large enough such that your structure and vacuum and present in it
Thank you so much. I think a vacuum of 20nm in all directions should be sufficient. How I make clear that QD lies within this region, I think the size of QD should be very small compared to this vacuum. Please tell me whether I'm right or not?
Your help is very appreciable. Again thanks.
@@Priya-gr9ee 20 angstroms is fine - not 20 nm. 20 nm is equal to 200 angstroms - and that’s far too large.
You can center the dot to the center of the unit cell through some linear algebra to the atomic coordinates, in which ever programming language you prefer
Thank you..
Thank you for your tutorial. Could you exlplain how to build a supercell made of this QD and and some vacuum between the QD's facets and the supercell's boundaries?
Hey … what exactly do you mean?
I would like to ask you a question about generating the QD of alpha-sulfur. If you could explain, the QD generated from this method does not look correct to me for sulfur.
Do you know how to make a CdTe quantum dot?
Really helpful video sir,
Could you please tell me how to build 2D quantum dots like PtS2, MoS2, WSe2.
Thanks in advance
helpful video..sir how we design 2d square monolayer of any metal like Ag ,Au .
I hope to make this type of video soon
@@nickelandcopper5636 I'm looking forward to that!!
What are the lattice parameters for this QD? I did for SnO2 tetragonal structure and VESTA shows a=b=c=1.0. Is right? Finally, are the atomic positions in cartesian coordinates?
Thanks.
The coordinates depend on how you save them. If you save as xyz I think they are Cartesian. If you save as a vasp you have option of direct or cartesian. The quantum dot has no lattice - it is a cluster model. Just save it as a .xyz file, and you won’t have to worry about lattice parameters
Ok. Thanks.
Hi, Thanks for this tutorial. can you also teach us how to draw truncated octahedron Pt nanoparticles by VESTA?
Hi, thanks for the very nice tutorial. I wonder if you ever tried to is to construct a core-shell structure?
Thanks. I have and it’s tough. There are a few ways to do it. The easiest is to cut out a spherical center in the shell structure and place a QD in it. Then, only leave 1-2 layers of shell followed by a geometry optimization.
@@nickelandcopper5636 Hi, thanks for the reply. It seems similar to what you did in the Pt@Pd video (if i remembered correctly). I guess, the challenge is how to construct the interface binding structure. Still unclear to me.
Anyway, your videos are really helpful. Thanks for the sharing these!
Very good. I have subscribed to your channel. Can we make a similar QD , say for CdS, or perovskite etc.? and what will be the difference we need to follow for multi element QDs?
I have one for CdSe and graphite. For the binary or ternary QDs, you will have a broken stoichiometry. When the stoichiometry is preserved you have a special case called a magic cluster. This however would need simulated annealing to make and cannot be made solely by cutting the crystalline structure. In other words, you would need to do some form of structure optimization to get the magic clusters. Cutting the bulk crystal to get a quantum dot where all atoms are bonded fully you will break stoichiometry. In the CdSe case I show, I think it is Cd rich
Sir, Is it possible for a QD to calculate is photoluminescence Quantum Yield using DFT tool?
Of course it is, but I really have only used DFT to compute absorption energies in QDs
Thank you sir for replying, your responses give me courage and are very helpful. Till now, I thought photoluminescence is a experimental phenomenon and can not be find out theoretically. Do you know someone who is calculating the same using DFT or provide me reference. Also, if you don't mention, it will be very helpful if you give your email address so that it will be easy to communicate and discuss about some problems.
@@Priya-gr9ee sure. At this point your best course of action will be to go to Google scholar and search “photoluminescence density functional theory” and collect 10-20 references. Read the sections of those papers where they explain how they calculate this property. Also spend time just search around Google for discussion forums. This type of searching is very important, and should be done carefully. Spend up to several weeks carefully doing it. It may seem like a waste of time but actually it sets a proper foundation for your future work. There is a famous saying that 1 day in the library (reading literature) is worth 1 week of work
How about constructing a carbon quantum dot? Is it possible here?
Of course. Which phase? Bulk cubic? I also have a video for a graphite quantum dot.
@@nickelandcopper5636 Bulk
How advisable it is to follow the same procedure to construct one?
It is advisable. Use your best judgement though for the final product. Always compare with the available literature if you can. If not, then be prepared to argue why you should be using what you get. This process should work for a quantum dot of crystalline bulk carbon
@@nickelandcopper5636 Can you please elaborate?
could you please demonstrate structure of MOF 5
Hi. Can you please be more specific?
Sure it’s a zinc mof Zn4O(BDC)3
Just letting you know I haven’t forgot about this - just having a lot of other things to do at this time
Hi what exactly would you like me to demonstrate?
Nickel and Copper
A 3 d structure of mof 5