I Have a Research Support System

After dinner, Xu Qiu did not go to the laboratory, but returned to the dormitory early.

No one is in the dormitory, Ren Bin probably hasn't returned to school yet, Tao Yan doesn't know where to go.

Did he go to the lab too? Today is Sunday.

Forget it, leave him alone.

Xu Qiu lay on the bed, entered the simulation laboratory, and opened the system interface.

The senior sister's DFT skill proficiency is only 50% at the third level. If you want to perform 100% deduction at the fifth level, you need to upgrade first.

"System, deduce the DFT proficiency to the fifth level."

[To deduce DFT to the fifth order 0%, 50%*100+1000=1050 points are required. Is it deduced? 】

"Deduction."

[The deduction is successful. 】

"System, spend 500 points to exchange for one fifth-order 100% DFT teaching, limited to polymer analysis."

[Successful exchange. 】

A virtual image appears.

Before using the DFT simulation software, the simulated villain first typed a mysterious code, put the generated file in the root directory of the software, and then opened the software.

A new plug-in appeared next to the software interface, and the simulated villain entered a lot of parameters into it.

Finally, he imports the molecular structure of the polymer's individual building blocks and runs the software.

After about twenty minutes, the computer came up with the simulation results, and Xu Qiu fast-forwarded the calculation process.

He found a serious problem.

That is, the molecular structure of the polymer macromolecule demonstrated by the simulated villain is quite different from that of the conjugated copolymer used in organic photovoltaic materials.

Xu Qiu was a little annoyed, he was still hasty, and should be more specific, such as limiting the analysis of conjugated copolymers.

But he didn't give up, he continued to read, and fast-forwarded to the next one when he encountered a structure that was not what he wanted.

Fortunately, it didn't take long, after only a dozen clips, he got the high-order simulation calculation method of the conjugated copolymer.

He recorded the mysterious codes and parameters into the big computer in the simulation laboratory.

Although he can't fully understand the specific functions of these codes and parameters, it doesn't prevent him from using them directly.

...

Xu Qiu quit the advanced teaching video and returned to the simulation laboratory, intending to try the advanced version of DFT simulation.

After thinking for a moment, he decided to test the waters with the classic PTB7-TH molecule.

He also copied his laptop into the simulation laboratory, opened the Chemdraw software, and drew the two structural units of PTB7-TH.

Among them, unit D is BDT, and unit A is TT.

Then import the molecular structure into the large computer, set the parameters, and start the simulation.

After more than twenty minutes, the calculation was completed.

The speed is a bit slow, Xu Qiu thought, maybe he can find a high-performance computer to help him do simulation calculations, the one that can produce results in seconds is the best.

"System, can you copy the supercomputer for me?"

[Insufficient authority, request rejected, the current host can only copy items and skills within 10 meters. 】

Well, it doesn't seem to work.

Moreover, he has no chance to contact supercomputing centers in the short term. As far as he knows, there are seven supercomputing centers in the country, but none of them are located in Shanghai.

However, he can settle for the next best thing.

Going to the school to do computational physics, computational chemistry, or computational materials science laboratories, a server capable of high-performance computing should be enough for the time being.

For example, Mr. Wei is doing "first-principle calculations of inorganic semiconductor materials and dielectric materials" to Professor Pei Zicai in Office 219.

Xu Qiu has taken Pei Zicai's "Computational Materials Science" course, and this teacher is quite interesting.

When he was in class, he couldn't help laughing, and he couldn't control his facial expressions very well, so his classmates called him "Pei Haha" privately.

...

While waiting for the calculation results, Xu Qiu also found a lot of literature on PTB7-TH, and summarized the performance of PTB7-TH, mainly energy level and forbidden band width.

After comparing with the literature, it is found that there is still a certain gap between the simulated data and the actual data, and the deviation value is about 0-0.4 electron volts.

Compared with the original unimproved version, this gap is already very small.

In the original DFT simulation, because the macromolecular material is calculated as a small molecular material, the error of the tested energy level is usually above 0.5 eV, and the error of the forbidden band width even exceeds 1 eV.

You must know that for suitable photovoltaic materials, the bandgap width is between 1-2 electron volts, and the error is close to 50%, which cannot even be called an error.

This is also the reason why the senior sister said that fewer and fewer people use this method.

For the small error that still exists after the improved version, Xu Qiu also considered the possible reasons:

On the one hand, for a molecule like PTB7-TH, one of its structural units, TT, is not axisymmetric, so its arrangement in the macromolecule is uncertain.

If all the TT units are arranged in one direction, the resulting macromolecular material will have stronger crystallinity, smaller bandgap, and generally better performance.

On the contrary, if it is randomly arranged, the performance of the material is poor.

On the other hand, he has studied "Organic Chemistry" and knows that there are side reactions in all synthetic reactions.

Ideally, you want the small molecular units to join hands in a straight line, forming a straight macromolecular chain.

But the actual situation may be that some people hold other people's feet, some people's hair is pulled by others, and some people have broken arms and legs.

Although the possibility of the above situation happening is very small, maybe only 1%-5%.

But for tens of hundreds of such people, there will always be various accidents, resulting in the final material not being ideal, but having defects.

Therefore, the theoretical results still need to be tested by practice after all.

...

Xu Qiu used software to draw the molecular structure he envisioned, and then performed advanced DFT simulation calculations.

He chose the benzothiadiazole BT unit with a simple structure for A unit, and thiophene for D unit, from one thiophene to four connected thiophenes, namely T, 2T, 3T, and 4T.

The simulation calculation takes one and a half hours, and he turned on 2 times the time acceleration.

During this period, because he couldn't leave the simulation laboratory, he simply made a group meeting PPT in it.

Last week, the senior sister took into account that he was participating in the group meeting for the first time and had no experience, so she explained his work for him, and this week he will play by himself.

The first is the experimental progress this week, including repeatability testing and stability testing of device performance.

Then there's the synthetic route to the molecule he designed.

It appears that he designed four molecules, but in reality there are four types of molecules, because the synthesis is so variable.

For example, the size, type, position, and quantity of branch chains can be changed, whether heteroatoms can be introduced, the position and quantity of heteroatoms can be changed, and so on.

After he completed the PPT of the group meeting, all the simulation results came out.

From the perspective of energy level structure and forbidden band width, the four types of molecules are all suitable photovoltaic materials.

However, it is only theoretical.