I Have a Research Support System

Originally, Xu Qiu planned to have an in-depth exchange with his senior sister about the direction of "non-fullerene derivatives".

But I didn't expect that she only had a preliminary concept.

This is also a discussion * oh.

This situation is very similar to when she proposed to integrate perovskite materials into the organic photovoltaic system.

At that time, she only mentioned one concept, and the rest of the content was developed by Xu Qiulai.

However, it is also a blessing that the senior, who has always been salty, is willing to step out of the comfort zone filled with water in the second district.

You can't beat people for it.

It's better to be silent.

...

After Xu Qiu finished revising a few articles proposed by her senior, she went to the laboratory to find Han Jiaying.

At this time, she is testing the device, and judging from the stacked state of the substrate next to it, she should be almost finished testing it.

Generally, before device testing, they will pay more attention to the protection of the substrate surface, and each piece must face up and be neatly stacked.

But for the substrates that have been tested, especially those with low efficiency, they can be placed more casually, because they may be recycled soon.

In the field of organic photovoltaics, the main experimental work is the synthesis of materials, as well as the preparation of devices and the optimization of conditions, which have relatively large variables.

As for other aspects of characterization, the experimental operation is relatively fixed. As long as there are no major mistakes, what is measured is basically what it is. It mainly depends on how the researchers analyze the experimental data.

Therefore, after synthesizing a batch of materials, Han Jiaying's main work now is to prepare and test devices.

"How, is the test almost finished?" Xu Qiu asked.

"Come on, I'm going to test the four systems of senior brother first, and the highest efficiency is 9.8%, which is not as high as what you did before." Han Jiaying said:

"However, the performance trends of the four systems are basically consistent with what you have obtained. As the number of branched carbon atoms increases, the efficiency first increases and then decreases, and the 2OD side chain is the extreme point."

"The trend is the same. It doesn't matter if the efficiency is higher or lower. Besides, you are using aluminum electrodes instead of silver electrodes. It's normal to have lower performance." Xu Qiu said:

"Then, what about your two systems P3T and P5T, after changing the branch chain, is there any obvious change in device performance?"

"The performance of the P3T system has not changed much. With the shortening of the side chain, the efficiency has increased from 6.20% to 6.42%," Han Jiaying said:

"But the P5T system, the change is quite obvious. As the side chain becomes longer, the efficiency jumps from 4.01% to 5.88%."

Xu Qiu thought for a moment and said:

"This phenomenon is quite interesting. It seems that for the P5T system, before and after the change of the side chain is just an important critical point, while the P3T system is not.

P5T is somewhat similar to my original P4T system. In the latter, the side chain changes from 2HD to 2OD, and the efficiency is greatly improved, and then to 2DT, the efficiency drops slightly. "

"Brother, can you post an article about this discovery?" Han Jiaying said.

"It's impossible to think too much, you, you think about articles all day long," Xu Qiu said with a smile:

"The weight of this discovery is not enough, it just describes a phenomenon, at most it becomes a one-sentence description, which is written in the article.

Unless I can analyze the reason behind this phenomenon, then it's almost the same, but I don't have this ability now. "

"That's it," Han Jiaying nodded half-understanding, and said:

"But I remember Senior Sister Chen Wanqing, she planned to do an experiment on the crystallinity of P4T-2OD that changes with the treatment temperature. Doesn't that also describe a phenomenon?"

"It's not the same," Xu Qiu said:

"Because she can combine light absorption spectroscopy, transmission electron microscopy, atomic force microscopy, grazing incidence X-ray diffraction and other characterization methods for comprehensive analysis.

In other words, she can make many representations and can tell a complete story, and my discovery is just the beginning of the story. "

"I seem to understand. Judging by the tone of your speech at the time, I thought you had another article." Han Jiaying said.

"I'm just expressing my feelings. If you want to irrigate, it doesn't mean that you can irrigate it just because you say it." Xu Qiu laughed.

...

The junior girl continued the experiment, Xu Qiu stood beside her and began to analyze:

At present, it seems that her proficiency in preparing devices is already very high, and she has mastered various instrument operations and several spin-coating methods.

And based on his system, Xuemei also repeated the efficiency of 9.8%. He didn't use silver electrodes at the beginning, and the highest value was only 9.99%, which is not much different.

As for her two systems, P3T and P5T, most of the known experimental optimization methods that can be used, including introducing fluorine atoms, regulating side chains, and true thermal spin coating, have almost been used.

This shows that the potential of these two systems has been exhausted.

Unless there is another subversive experimental optimization method, the situation can be turned around.

But think about it and know that it is not easy.

Then, in the final result, the device efficiency of P3T and P5T is likely to hover between 6% and 8%.

The corresponding article level is roughly one to two.

There is a high probability that two articles can be published, because there are almost no reports on similar molecular structures. Although the structures of P3T and P5T are somewhat similar, they are different structures after all.

If one has an efficiency of 6% and the other has an efficiency of 7%, it would be more appropriate to send 6% first and then 7%.

This is the advantage of doing your own synthetic experiments.

Because many groups are not synthesized, a threshold is formed.

As long as the level of device preparation is high enough, and the molecular structure is slightly changed to get a similar result, an article can be published.

From this point of view, it was quite lucky that Xu Qiu chose to start testing the waters from the P4T system.

Of course, it's not entirely luck.

At that time, when he selected materials, he didn't just roll a dice. He had his own considerations as to whether the number of points was a few T or not.

First of all, Xu Qiu summed up a set of his own theory based on the DFT results reported in the literature:

In the DFT results, the energy level distribution is generally uniform, which can ensure the conjugation properties of the material and is beneficial to charge transport. The HOMO/LUMO energy levels are concentrated on the D/A unit, which is helpful for exciton splitting.

Molecules with this structure will most likely perform better.

Then, he used high-order DFT simulations to calculate the four molecules from P2T to P5T, and carefully observed the HOMO/LUMO energy level distribution diagrams of these molecules.

P4T performed best, followed by P2T, and finally P3T and P5T.

On the whole, the energy level distribution of P4T is relatively uniform, and there is distribution on each structural unit, and the conjugation of molecules is relatively good.

And its HOMO/LUMO energy levels are respectively concentrated on the D unit 2T and the A unit 2TBT.

It not only conforms to his theory, but also proves that the performance is really good in practice.

Xu Qiu infers that such a situation may be related to the symmetrical structure of P4T.

Relatively speaking, the asymmetric P3T and P5T are worse.

But this theory is not perfect.

For example, P2T is also a symmetrical structure. Judging from the HOMO/LUMO energy level distribution diagram, the molecular conjugation is relatively good, but its performance is the bottom of the four groups of materials.

This shows that there are other factors outside the theoretical framework that have affected the results.

What is the specific impact, the current Xu Qiu is also difficult to analyze.

After all, the complexity of a material with hundreds or thousands of atoms on a microscopic scale is unimaginable.

Thank you, I'm really fat, for rewarding 200 starting coins, Lanzang Wenyuan, and book friends 20201022235159250 for rewarding 100 starting coins.