I Have a Research Support System

After the group meeting, everyone returned to 216.

After a while, Wu Feifei suddenly said excitedly: "My visa has been approved, Xu Qiu, Han Jiaying, go check it out."

Xu Qiu glanced at Wu Feifei's computer screen. The page on the browser was the Pretty Country Visa Center, with "Issued (issued)" marked on the top, and the applicant's AA code, passport issuance date, and a paragraph in English below. Remarks: "Your visa has been approved. If you do not receive the visa within 10 working days, please contact..."

"It's pretty fast." Xu Qiu responded casually, and then checked with Han Jiaying, and found that their visa status also showed "Issued", so he said, "Our visa has also been approved."

"You are all lucky, none of you have been reviewed, "I just don't know how long the visa is valid for..." Tian Qing explained: "For example, there are several grades of validity for tourist visas in the beautiful country, which are 3 Months, 1 year, 3 years, 5 years, and 10 years are also permanently valid. The validity period of the tourist visa I applied for before is 5 years, which is relatively long. "

"By the way, after you receive your passports, remember to go to the EUVS website to update your information. This must be updated before you go to the beautiful country. If you don't update it, your subsequent entry will be affected." Tian Qingdun After a pause, he added:

"Oh, and this website is free. Sometimes if you go directly to Qiandu, you will find a fake official website, and then you will be charged a handling fee of tens of knives. Remember not to be fooled by Qiandu."

Wu Feifei responded with a smile: "I didn't expect Qiandu's business to expand so extensively. It used to accept advertisements for shoes and hospitals, but now it has successfully connected with the international market."

...

After lunch, Xu Qiu went to the Jiangwan campus alone. His work plan for this week was to synthesize the Y-series receptor materials, and at the same time finish the writing of the "Joule" article between experiments.

Both Han Jiaying and Wu Shengnan stayed at the Handan campus. This week, the junior girls will prepare battery devices based on PTQ1 and conduct other characterization tests; the postdoctoral senior sisters will communicate with Wei Xingsi about the writing of the fund project in real time this week.

Seeing this, the other two undergraduates, Yin Houlang and Xu Xinjie, stayed on the Handan campus.

In fact, Xu Qiu didn't mind bringing the two newcomers with him, but the attitude of the new undergraduates towards him was somewhat special...

How to describe it? Probably respectful and alienated, a bit similar to how he looked at Wei Xingsi when he first joined the group.

Unknowingly, Xu Qiu's identity as a student was quietly fading away, gradually transforming into the leader of a research team.

After one o'clock in the afternoon, Xu Qiu arrived at the Jiangwan campus, and first went to the student office on the fourth floor of Xiancai to rest.

Someone moved into the big office here today. Three men and one woman seemed to belong to the same research group.

Xu Qiu speculated that it might be that the labs of other research groups in Jiangwan had almost been renovated, and they planned to relocate to Jiangwan in response to the school's call.

However, Xu Qiu didn't know any of these four people, so he didn't greet them, and directly took out the key to open the door and entered the small office in the inner room.

Scanning around the office and seeing Han Jiaying's desk, Xu Qiu decisively chose to "occupied the magpie's nest" and occupied the seat of the school girl.

Because there is a cushion on the chair of the school girl, it is more comfortable to sit on, and the surrounding decoration is also very good, which can make people feel happy and get a BUFF of +10% work efficiency.

Sitting on the chair, Xu Qiu turned on his laptop and began to plan the experiment plan. He could vaguely smell the scent left by the school girl, but he didn't know if it was an illusion.

In the design of Y-series acceptor materials, Xu Qiu actually considered "simplifying the synthesis steps of acceptor materials and reducing the cost of acceptor materials" at the beginning of the design.

For example, the synthesis of Y5 material is because Y4 uses the ICIN-2F end group which is relatively difficult to synthesize, so it is replaced by the ICIN-2Cl end group.

Originally, Xu Qiu didn't expect the performance of Y5 to be very good, but it turned out that the performance of Y5 was even better than that of Y4, and the highest device efficiency reached 14.8%.

During this period of time, Xu Qiu also made further "optimization" on Y5 by referring to the experience of the previous ITIC system.

Using the simulation laboratory, Xu Qiu designed and synthesized Y6-Y11, a total of 6 receptor materials.

It is a pity that the device performance of these materials has not made further breakthroughs, and still stays at the level of 12-14% efficiency.

Specifically, Y6 is regulated relative to Y3. Changing the ICIN of the Y3 end group to ICIN-M is considered to be the same series of materials as Y4 and Y5. Although the device efficiency is slightly worse than Y4, it has reached 14 %+.

The subsequent Y7-Y11 are all "improvement" relative to Y5.

Among them, Y7 is to replace the thienothiophene TT connected to the NT unit in Y5 with thienothiophene TTT to widen the conjugation length of the central unit, and the highest efficiency is 12%+.

Y8 and Y9 are to modify the side chain on the nitrogen atom of the NT unit in the Y5 molecule. Y5 uses 2-ethylhexyl, Y8 uses a straight-chain alkyl group with the same number of carbon atoms—n-hexyl, and Y9 uses The 2-butyldecyl group in which the number of carbon atoms is increased by 4. The efficiencies of Y8 and Y9 are both 13%+, not exceeding Y5.

Y10 and Y11 are to modify the side chain on the N atom at the junction of the NT unit and the TT unit in the Y5 molecule. Y5 uses the same 2-ethylhexyl, and Y10 and Y11 are n-hexyl and 2-butyldecyl respectively. The efficiencies of Y10 and Y11 are both 14%+, also not exceeding Y5.

These experimental results show that, on the one hand, the "base" of the Y series materials is relatively good, and the average efficiency is 12%-14%, while the average level of the previous ITIC series is 10%-12%, and the earlier PDI series , at 6%-8%.

Molecular structure largely determines the upper performance limit of a material.

On the other hand, it also shows that the Y5 material has been optimized relatively well.

If you want to further improve, you can't "make small troubles", but need to make larger adjustments to the central unit, such as replacing the NT unit with other units.

Xu Qiu produced a series of ideas in his mind, and handed them over to the simulation laboratory to explore on his behalf.

His top priority now is to synthesize the first-generation Y-series materials in reality.

Xu Qiu's target materials are Y3, Y4, Y5, and Y6. The central unit of these materials is the same, only the end groups are different, which can be "one pot", which greatly saves time.

As for Y1 and Y2, they were temporarily given up by him.

In theory, they can also be synthesized, water two articles in one district, but that is not necessary.

Even for the four materials Y3-Y6, Xu Qiu doesn't plan to write too many articles, because now he has only one goal, which is the main publication of CNS.

If you optimize a little bit every time and publish one article, of course the number of articles will be more, maybe five or six articles of the AM, JACS, EES level, but you may miss the opportunity to be the top CNS main journal.

This is not only for system tasks, but also for my own scientific research career.

The gold content of one piece of "Nature" is higher than that of ten AM articles.

Basically, with an article in "Nature", it is a matter of time before it is promoted to the position of "Jie Qing" in China.

Therefore, Xu Qiu's plan was to hold back a wave of big moves first, and then directly hit Wang Bo, raising the efficiency to a very high level at once.

For example, reach a recognized threshold of 15% in the field of organic photovoltaics, or even break through this threshold, reaching more than 16%.

In this case, there is still a good chance of impacting a CNS.

It can be imagined that the colleagues of organic photovoltaics are still working hard for the efficiency to break through 13% ("Natural Energy" with an efficiency of 13% has not yet been published), if it does not take long for an article to directly achieve the efficiency of 15, 16 %, how shocking that would be.

The specific synthesis scheme planning, because the terminal A unit of the Y3-Y6 material is the ICIN derivative used in the previous ITIC system, so there is no need to re-synthesize, and the main consideration is the synthesis of the central D unit.

In fact, strictly speaking, the molecular structure of the Y series receptors is no longer the ADA structure of the ITIC system.

The nature of the central NT unit is close to the A unit, and the TT units on both sides of the NT are close to the D unit, plus the terminal A unit, so the Y series receptor is actually a molecule similar to the ADADA structure.

Xu Qiu speculated that the ADADA molecular structure of the Y series receptors may be a major reason for their performance surpassing the ITIC series materials.

Of course, looking for the reason for performance improvement is a later matter, and we still have to work on the synthesis of materials.

The synthesis of Y3-Y6 requires six steps of reaction, and the synthesis steps of the first five steps are exactly the same, so only one pot reaction can be cast.

In the first step, a dibromo-substituted benzotriazole (NT) unit with an ethylhexyl side chain on the nitrogen atom connects two nitrates at the remaining two reactive sites on the benzene ring through a nitrolation reaction. base, to obtain NT units substituted by dibromo and dinitro groups.

In the second step, the dibromine, dinitro substituted NT and monotrimethyltin substituted TT units were reacted to obtain a structure of TT-NT-TT, in which two nitro groups were attached to the NT.

The third step is to reduce the nitro group in the TT-NT-TT molecule and form a ring with the adjacent TT unit to form a ring-shaped secondary amine (a compound formed by replacing the two hydrogen atoms on the ammonia molecule with a hydrocarbon group) , to obtain a continuous fused ring structure with a conjugation length of 7, that is, seven five-membered and six-membered rings are connected in the form of fused rings. At this time, there is a secondary amine located between TT-NT in the product, and there is a residual hydrogen atom on it, which is a reaction site.

In the fourth step, react the reactants of the third step with brominated alkanes, replace the hydrogen atoms on the secondary amines with alkyl groups to form tertiary amines, realize the purpose of introducing side chains on N atoms, and obtain the final central DAD unit.

In the fifth step, the aldylation reaction of the central DAD unit connects two aldehyde groups at both ends of the central DAD unit.

The sixth step is to react the aldylated DAD unit with ICIN, ICIN-2F/2Cl/M and other A units to obtain Y3-Y6 series acceptor materials.

After making preparations for the experiment, Xu Qiu entered the chemical laboratory on the fifth floor of Xiancai, put on protective gear, and started the experiment.

The first step reaction is to carry out nitration reaction on the NT unit.

Starting materials are dibromo-substituted NT units, nitric acid and trifluoromethanesulfonic acid.

Among them, trifluoromethanesulfonic acid is a new reagent.

It is also known as trifluoromethanesulfonic acid. It is easily soluble in water, has low toxicity, and has a wide range of uses.

In terms of molecular structure, trifluoromethanesulfonic acid is a product in which a hydrogen atom in a sulfuric acid molecule is replaced by a trifluoromethyl group, and its acidity is stronger than that of 100% sulfuric acid.

In many occasions, trifluoromethanesulfonic acid can replace traditional inorganic acids such as sulfuric acid and hydrochloric acid, and play a role in optimizing and improving the process.

Considering that the NT unit is relatively cheap, and that four kinds of materials will be synthesized this time, the demand for raw materials is relatively large. In addition, the photoelectric performance of the Y series materials has been verified by the simulation laboratory. Xu Qiu is also doing simulation experiments Relevant synthesis experiments have been rehearsed in the laboratory, so he decisively carried out large-scale synthesis.

First, take out a washed and dried two-neck flask from the oven.

Then, weigh the reactant NT monomer, 10 grams, and put it into the reaction bottle.

Next, draw concentrated nitric acid, 35 ml, into the reaction bottle.

Finally, pipette trifluoromethanesulfonic acid, 5 mL, into the reaction flask.

When adding trifluoromethanesulfonic acid with a disposable dropper, Xu Qiu found that this thing would also fume in the air like oleum and fuming nitric acid, probably because it inherited the water absorption of sulfuric acid.

This step of nitration reaction is not very difficult, because for the dibromo-substituted NT unit, which has fewer reaction sites, there are fewer side reactions that may occur.

However, if there are many reaction sites, the nitration reaction will be somewhat difficult.

For example, when Xu Qiu was doing 3D-PDI before, he once did a nitrolation reaction, and as a result, several products were directly synthesized, and they could not be separated and purified at all, so the experiment directly failed.

In the evening, Xu Qiu processed the product and purified it by using a column method. The yield of this step was very high, reaching 93%.

However, due to time constraints, there is no way to proceed with the second step of the reaction.

The main reason is that there is no bed to rest on the Jiangwan side, so the experiment must be finished before the last school bus, otherwise, they can only take a taxi or ride a bicycle back to the Handan campus.

The Handan campus is not far from the Jiangwan campus. According to Sun Wo, if you ride a bicycle, you can get there in half an hour. However, Xu Qiu has never tried it, and he doesn't want to try it for the time being.

The reason why Sun Wo knew it was because he did not apply for a student dormitory after he enrolled, and he still maintained the habit of cycling home every day during the summer vacation, and he knew a lot about cycling.

I don't know if Sun Wo is just trying to save one or two thousand a year in accommodation fees, or for exercising, or for other reasons.

On Tuesday, Xu Qiu went to the Jiangwan campus again.

Continue the reaction of the second step, and react yesterday's reactant with the TT unit substituted by monotrimethyltin.

This step is a Stille reaction of small molecules, and there are not many side reactions. It is relatively easy to complete the reaction of all reactants as much as possible.

Therefore, Xu Qiu directly uses a microwave reactor to provide a relatively severe reaction condition, which can simultaneously increase the yield of the reaction and shorten the time required for the reaction.

In the afternoon, Xu Qiu got the crude product, filtered, rotary evaporated, and passed through the column to obtain an orange-red product with a yield of 82%.

Continue to the third step reaction, which is the reduction of the nitro group.

What is used is the purified second-step product and triethyl phosphate, o-dichlorobenzene as the reaction solvent, which needs to be heated and refluxed overnight.

This step of the reaction is not difficult, you just need to carefully add each reagent into the reaction bottle, and then set up the equipment.

The only thing worth mentioning is that the new reagent used this time, triethyl phosphate, is a colorless liquid with a low viscosity and a slight fruity aroma.

When Xu Qiu was buying medicine, he almost bought triethyl phosphite by mistake.

This is because the English names of Triethyl phosphite and Triethyl phosphate are so similar, there is only one difference between the letters "i" and "a".

From this point of view, Chinese drug names still have advantages, with the addition of the word "Asia", the difference between the two can be seen at a glance.

It is no wonder that the Chemical Abstracts Service (CAS), a subsidiary organization of the Beautiful National Chemical Society, will issue CAS numbers to distinguish different substances. Otherwise, it is estimated that many people will be confused when using other drugs due to the similarity of the English names. mistake.

The point is, for chemical reagents, the difference is a thousand miles away.

Although there is only one word difference between triethyl phosphite and triethyl phosphate, the molecular structure is only that the latter has one more phosphorus-oxygen double bond than the former, and the difference in physical and chemical properties will be very large.

For example, triethyl phosphate can be completely soluble in water, while triethyl phosphite is almost insoluble in water.

On Wednesday, continue experimenting.

Xu Qiu post-processed the product of the third step reaction, and directly removed the solvent by rotary evaporation, and the obtained crude product was used in the fourth step reaction.

This step does not require purification, because even if there are side reactions and by-products formed here, it will not affect the next experiment, so there is no need for purification.

When doing synthesis in an organic laboratory, try to reduce the experimental steps as much as possible under the premise of ensuring that the experiment will not fail.

The time saved, whether it is to continue to do experiments, write articles, or paddle water, is very good.

The reaction in the fourth step is to introduce a side chain on the secondary amine, and the product of the third step, bromine-substituted ethylhexyl, potassium iodide, potassium carbonate, and DMF solvent are used.

At the beginning, Xu Qiu chose to use relatively short 2-ethylhexyl as the side chain, considering that there is already a side chain on the NT unit, and there is no need to use a relatively long side chain to meet the basic solubility requirements of the material.

Later, the results of Y10 and Y11 also showed that Xu Qiu's original idea was correct.

This reaction needs to be reacted for 10 hours at 90 degrees Celsius in the dark.

In the evening, Xu Qiu processed the product of this reaction, extracted it with ethyl acetate, washed it with water, dried it, and passed it through the column.

Because the conjugated structure of the material did not change much, the obtained product was still orange-red.

For organic photovoltaic materials, the main color is the conjugated structure, and the influence of side chains on the color of the material is relatively small.

Due to limited time, Xu Qiu did not have time to vote for the next step five.

On Thursday, continue the Jiangwan experiment.

However, today is quite special, Xu Qiu's courses for this semester are all selected on this day.

Early in the morning, he sent an email to several teachers, sincerely asking for leave, saying: "There is an important continuous experiment that needs to be carried out. I hope to ask for a day off, and I hope for approval."

Speaking of which, Xu Qiu hasn't skipped many classes this semester.

The main reason is that he is now well-known in the department, so many teachers know him, so they will take extra care of him in class and often ask him to answer questions.

This made Xu Qiu not dare to skip classes as brazenly as he did when he was an undergraduate, even if these teachers didn't call names.

Regarding the matter of asking for leave, in fact, what most teachers want is an attitude. You don’t have to come to the class, but you have to tell me to show respect. Very few teachers will not grant leave.

Sure enough, not long after Xu Qiu sent the email, at seven or eight o'clock in the morning, he received an email reply from the teachers, saying that they were allowed to leave.

Today is the fifth step reaction, that is, the reaction of adding aldehyde groups, which requires the use of liquid nitrogen to add aldehyde groups to both ends of the central DAD unit.

The reaction is not difficult, but it is troublesome. The main reason is that there is no low-temperature physics laboratory on Jiangwan, and liquid nitrogen needs to be brought from the Handan campus.

And with liquid nitrogen, you can't take the school bus, you can only carry the liquid nitrogen container filled with liquid nitrogen, and then take a taxi to send the liquid nitrogen there.

In the end, after a whole day of tossing, at night Xu Qiu finally got the fifth step reaction product purified by the column.

Originally, 10 grams of NT raw materials were used, but after this step, only 5.35 grams were left.

Still, it's perfectly acceptable to have this amount.

If it is distributed evenly, more than 1 gram of each material in Y3-Y6 can be synthesized, which is enough for the time being.

After finishing the experiment, Xu Qiu took the school bus back to Handan, dragged his tired body back to the dormitory, took a hot shower, and the fatigue subsided a lot.

Now that I have been upgraded to a Ph.D. student, with 24-hour hot water supply, I finally don’t have to take cold showers every day like an undergraduate student.

On Friday morning, Xu Qiu stayed at the Handan campus.

Today he has to perform his duties as a teaching assistant. On the one hand, he will evaluate the PPT speeches of undergraduates in Mr. Wei’s course, and on the other hand, he will lead them to visit the laboratory.

Although Xu Qiu hadn't done these things before, he had accumulated a wealth of experience in Wei Xingsi's group for more than a year, and it was not difficult for him to deal with this kind of thing.

I have to say that working in Wei Xingsi's group has a lot of things to do, but it's also really a lot of exercise.

There were not many students enrolled in this course, only a few, and all of them were present.

Originally, at the beginning of the semester, Teacher Wei wanted a few undergraduates who were new to the research group to take his courses.

As a result, when Wei Xingsi told them, the course selection time had already passed, and there was no way to modify the class schedule, so he had to give up in the end.

But they can wait until the next time Wei Xingsi starts a class and choose again. Basically, Mr. Wei's class can get a stable A, or at least a B+.

After all, it is Teacher Wei who is grading, and he will definitely give good grades to the students in his group.

Although this is "according to people and assigning points", it is unfair, but how should I put it, the national conditions are like this.

This is also the inertia of history, such as feudal remnants such as "predominance of boys over girls", which have not been completely cleared up until now.

The first is the evaluation of the PPT speech. Xu Qiu didn't bother the others, and pulled these students into the small conference room on the third floor of Caiyi alone.

In fact, it was relatively easy for him to call someone over to help, such as La Mowenlin or Han Jiaying.

But first, other people are also very busy, two people come to evaluate, the work efficiency is equivalent to directly halving, and second, after all, he has taken hundreds of dollars from the school every month, so he has to do things after taking the money.

The latter is also Mr. Wei’s philosophy. For example, when he asked Xu Qiu to review the doctoral thesis, or the materials for the associate professor’s regularization, he gave Xu Qiu the review fee. His idea was “whoever does the work gets paid”.

As for Xu Qiu and the others helping to review manuscripts, there is really no real reward for this, after all, manuscript review itself is voluntary labor.

But looking at it from another perspective, the reward has actually been received, but it is relatively empty, including that the article is more likely to be accepted, and it is less likely to be directly rejected by the editor, etc.

The students began to report one by one, and the speeches were all in English.

A few of them speak a little better English, and a few of them speak a little less English, but overall they are all okay.

After all, students who have the courage to choose an all-English course generally have two talents. Xu Qiu had never chosen an all-English course before.

Of course, he didn't choose courses in English mainly because he was afraid of trouble. For example, English courses taught by foreign teachers in English not only gave poor grades, but also usually had a lot of homework in class. Choosing such courses was purely for himself.

When Xu Qiu was listening to the students' reports, he didn't stay idle either. He used two things at once, filling out his teaching assistant's handbook at the same time.

The teaching assistants in the school will receive a booklet, which is used to record the situation of each class, the number of students who should attend, the number of students who have actually attended, the main content of the course, suggestions for the course, etc.

As for Xu Qiu, except for showing up at the beginning, he has never appeared in class since then, and now he can only rely on his imagination to complete the teaching assistant's manual.

In fact, Xu Qiu is not a special case. The teaching assistants of most courses do this.

Basically, we can see each other when the class starts, and we can see each other again when the exam is invigilated, and there is no one at other times.

The main reason is that there is no need to assign teaching assistants to many courses. Even if teaching assistants are assigned, there is no need to sit on the classroom in every class, but the teaching practice of teaching assistants is a compulsory credit for every graduate student.

It can only be said that many things in the school are very rigid, and there is almost no difference in the training plan for students with majors. For example, they must do teaching practice, must listen to several lectures, and must report at school-level meetings and above.

It may also be because there are too many postgraduate students and the school is not easy to manage, so it can only do one size fits all.

Moreover, many postgraduates do not study for scientific research, but for employment-based postgraduate study, that is, if they don't want to find a job, or can't find a good job, they will study for a postgraduate study for two or three years.

This is also a manifestation of the introversion of contemporary college students. It is difficult for fresh college students to find a job. Those who have the conditions to study for graduate school naturally tend to change their track. After all, some positions are limited to graduate students, and there will be more choices after graduate school.

The school's rigid restrictions may also be setting a bottom line, so that the masters and doctors cultivated are not so "ugly", at least they must have some scientific research literacy.

After the students had finished their speeches, Xu Qiu took the group to the 216 laboratory of Caiyi and had a tour.

One of the junior girls said after seeing the laboratory: "The area here is so small, so many instruments can be accommodated."

Xu Qiu joked: "Yes, all this is due to the designer of our laboratory, Senior Sister Wu Feifei."

Wu Feifei was doing experiments in the glove box. After hearing this, she gave Xu Qiu an angry look.

In fact, Xu Qiu was not entirely joking. When Wu Feifei was planning the laboratory, she was stunned to cram in the instruments and equipment that can only be placed in a normal laboratory of 60 square meters in a space of only about 30 square meters. The space utilization rate extremely high.

Lead to the newly purchased instrument later. For example, TRPL can only be placed in Teacher Wei's office.

Compared with the situation Wu Feifei encountered back then, when Xu Qiu designed the Jiangwan laboratory later, it was much simpler, the area was large, and it was willful.

After arranging the batch of undergraduates, Xu Qiu went to Jiangwan again in the afternoon to continue the experiment.

Han Jiaying also passed by with Xu Qiu, and the two of them were separated for several days, and they missed each other very much.

When the two arrived at Xiancai's office on the fourth floor, the junior girl found a hole in the upholstery of her own seat. She immediately understood what it was, and then showed a disgusted look.

Xu Qiu could only smile awkwardly. These days, his experiments were indeed progressing very quickly, but most of the time he was still typing in the office, liver "Joule" articles, so that's it.

For this reason, the two "fighted" in the office.

The final solution was that the school girl went to buy a new cushion, and the original cushion would belong to Xu Qiu.

After playing around, the two entered the laboratory and began the final reaction.

Xu Qiu took out 4 grams of the 5.35 grams of the central DAD unit, divided them into four parts, and reacted with ICIN/ICIN-2F/ICIN-2Cl/ICIN-M respectively in the environment of pyridine and chloroform solvents. Stirred and refluxed overnight, the target product Y3-Y6.

On Saturday, the two continued the liver explosion experiment, and Han Jiaying also accompanied Xu Qiu to Jiangwan to deal with the reaction. After four pillars, they finally got the four products of Y3-Y6.

After working for seven days in a row, with an average working time of 12 hours a day, Xu Qiu expressed a little hypocrisy.

Fortunately, the usual physical exercise is not bad, otherwise I might not be able to persist.

Of course, it's all worth it.

After successfully obtaining four sets of Y series materials, it is time to test the results.

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